1@chapter Encoders 2@c man begin ENCODERS 3 4Encoders are configured elements in FFmpeg which allow the encoding of 5multimedia streams. 6 7When you configure your FFmpeg build, all the supported native encoders 8are enabled by default. Encoders requiring an external library must be enabled 9manually via the corresponding @code{--enable-lib} option. You can list all 10available encoders using the configure option @code{--list-encoders}. 11 12You can disable all the encoders with the configure option 13@code{--disable-encoders} and selectively enable / disable single encoders 14with the options @code{--enable-encoder=@var{ENCODER}} / 15@code{--disable-encoder=@var{ENCODER}}. 16 17The option @code{-encoders} of the ff* tools will display the list of 18enabled encoders. 19 20@c man end ENCODERS 21 22@chapter Audio Encoders 23@c man begin AUDIO ENCODERS 24 25A description of some of the currently available audio encoders 26follows. 27 28@anchor{aacenc} 29@section aac 30 31Advanced Audio Coding (AAC) encoder. 32 33This encoder is the default AAC encoder, natively implemented into FFmpeg. Its 34quality is on par or better than libfdk_aac at the default bitrate of 128kbps. 35This encoder also implements more options, profiles and samplerates than 36other encoders (with only the AAC-HE profile pending to be implemented) so this 37encoder has become the default and is the recommended choice. 38 39@subsection Options 40 41@table @option 42@item b 43Set bit rate in bits/s. Setting this automatically activates constant bit rate 44(CBR) mode. If this option is unspecified it is set to 128kbps. 45 46@item q 47Set quality for variable bit rate (VBR) mode. This option is valid only using 48the @command{ffmpeg} command-line tool. For library interface users, use 49@option{global_quality}. 50 51@item cutoff 52Set cutoff frequency. If unspecified will allow the encoder to dynamically 53adjust the cutoff to improve clarity on low bitrates. 54 55@item aac_coder 56Set AAC encoder coding method. Possible values: 57 58@table @samp 59@item twoloop 60Two loop searching (TLS) method. 61 62This method first sets quantizers depending on band thresholds and then tries 63to find an optimal combination by adding or subtracting a specific value from 64all quantizers and adjusting some individual quantizer a little. Will tune 65itself based on whether @option{aac_is}, @option{aac_ms} and @option{aac_pns} 66are enabled. 67 68@item anmr 69Average noise to mask ratio (ANMR) trellis-based solution. 70 71This is an experimental coder which currently produces a lower quality, is more 72unstable and is slower than the default twoloop coder but has potential. 73Currently has no support for the @option{aac_is} or @option{aac_pns} options. 74Not currently recommended. 75 76@item fast 77Constant quantizer method. 78 79Uses a cheaper version of twoloop algorithm that doesn't try to do as many 80clever adjustments. Worse with low bitrates (less than 64kbps), but is better 81and much faster at higher bitrates. 82This is the default choice for a coder 83 84@end table 85 86@item aac_ms 87Sets mid/side coding mode. The default value of "auto" will automatically use 88M/S with bands which will benefit from such coding. Can be forced for all bands 89using the value "enable", which is mainly useful for debugging or disabled using 90"disable". 91 92@item aac_is 93Sets intensity stereo coding tool usage. By default, it's enabled and will 94automatically toggle IS for similar pairs of stereo bands if it's beneficial. 95Can be disabled for debugging by setting the value to "disable". 96 97@item aac_pns 98Uses perceptual noise substitution to replace low entropy high frequency bands 99with imperceptible white noise during the decoding process. By default, it's 100enabled, but can be disabled for debugging purposes by using "disable". 101 102@item aac_tns 103Enables the use of a multitap FIR filter which spans through the high frequency 104bands to hide quantization noise during the encoding process and is reverted 105by the decoder. As well as decreasing unpleasant artifacts in the high range 106this also reduces the entropy in the high bands and allows for more bits to 107be used by the mid-low bands. By default it's enabled but can be disabled for 108debugging by setting the option to "disable". 109 110@item aac_ltp 111Enables the use of the long term prediction extension which increases coding 112efficiency in very low bandwidth situations such as encoding of voice or 113solo piano music by extending constant harmonic peaks in bands throughout 114frames. This option is implied by profile:a aac_low and is incompatible with 115aac_pred. Use in conjunction with @option{-ar} to decrease the samplerate. 116 117@item aac_pred 118Enables the use of a more traditional style of prediction where the spectral 119coefficients transmitted are replaced by the difference of the current 120coefficients minus the previous "predicted" coefficients. In theory and sometimes 121in practice this can improve quality for low to mid bitrate audio. 122This option implies the aac_main profile and is incompatible with aac_ltp. 123 124@item profile 125Sets the encoding profile, possible values: 126 127@table @samp 128@item aac_low 129The default, AAC "Low-complexity" profile. Is the most compatible and produces 130decent quality. 131 132@item mpeg2_aac_low 133Equivalent to @code{-profile:a aac_low -aac_pns 0}. PNS was introduced with the 134MPEG4 specifications. 135 136@item aac_ltp 137Long term prediction profile, is enabled by and will enable the @option{aac_ltp} 138option. Introduced in MPEG4. 139 140@item aac_main 141Main-type prediction profile, is enabled by and will enable the @option{aac_pred} 142option. Introduced in MPEG2. 143 144@end table 145If this option is unspecified it is set to @samp{aac_low}. 146@end table 147 148@section ac3 and ac3_fixed 149 150AC-3 audio encoders. 151 152These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as 153the undocumented RealAudio 3 (a.k.a. dnet). 154 155The @var{ac3} encoder uses floating-point math, while the @var{ac3_fixed} 156encoder only uses fixed-point integer math. This does not mean that one is 157always faster, just that one or the other may be better suited to a 158particular system. The floating-point encoder will generally produce better 159quality audio for a given bitrate. The @var{ac3_fixed} encoder is not the 160default codec for any of the output formats, so it must be specified explicitly 161using the option @code{-acodec ac3_fixed} in order to use it. 162 163@subsection AC-3 Metadata 164 165The AC-3 metadata options are used to set parameters that describe the audio, 166but in most cases do not affect the audio encoding itself. Some of the options 167do directly affect or influence the decoding and playback of the resulting 168bitstream, while others are just for informational purposes. A few of the 169options will add bits to the output stream that could otherwise be used for 170audio data, and will thus affect the quality of the output. Those will be 171indicated accordingly with a note in the option list below. 172 173These parameters are described in detail in several publicly-available 174documents. 175@itemize 176@item @uref{http://www.atsc.org/cms/standards/a_52-2010.pdf,A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard} 177@item @uref{http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf,A/54 - Guide to the Use of the ATSC Digital Television Standard} 178@item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf,Dolby Metadata Guide} 179@item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf,Dolby Digital Professional Encoding Guidelines} 180@end itemize 181 182@subsubsection Metadata Control Options 183 184@table @option 185 186@item -per_frame_metadata @var{boolean} 187Allow Per-Frame Metadata. Specifies if the encoder should check for changing 188metadata for each frame. 189@table @option 190@item 0 191The metadata values set at initialization will be used for every frame in the 192stream. (default) 193@item 1 194Metadata values can be changed before encoding each frame. 195@end table 196 197@end table 198 199@subsubsection Downmix Levels 200 201@table @option 202 203@item -center_mixlev @var{level} 204Center Mix Level. The amount of gain the decoder should apply to the center 205channel when downmixing to stereo. This field will only be written to the 206bitstream if a center channel is present. The value is specified as a scale 207factor. There are 3 valid values: 208@table @option 209@item 0.707 210Apply -3dB gain 211@item 0.595 212Apply -4.5dB gain (default) 213@item 0.500 214Apply -6dB gain 215@end table 216 217@item -surround_mixlev @var{level} 218Surround Mix Level. The amount of gain the decoder should apply to the surround 219channel(s) when downmixing to stereo. This field will only be written to the 220bitstream if one or more surround channels are present. The value is specified 221as a scale factor. There are 3 valid values: 222@table @option 223@item 0.707 224Apply -3dB gain 225@item 0.500 226Apply -6dB gain (default) 227@item 0.000 228Silence Surround Channel(s) 229@end table 230 231@end table 232 233@subsubsection Audio Production Information 234Audio Production Information is optional information describing the mixing 235environment. Either none or both of the fields are written to the bitstream. 236 237@table @option 238 239@item -mixing_level @var{number} 240Mixing Level. Specifies peak sound pressure level (SPL) in the production 241environment when the mix was mastered. Valid values are 80 to 111, or -1 for 242unknown or not indicated. The default value is -1, but that value cannot be 243used if the Audio Production Information is written to the bitstream. Therefore, 244if the @code{room_type} option is not the default value, the @code{mixing_level} 245option must not be -1. 246 247@item -room_type @var{type} 248Room Type. Describes the equalization used during the final mixing session at 249the studio or on the dubbing stage. A large room is a dubbing stage with the 250industry standard X-curve equalization; a small room has flat equalization. 251This field will not be written to the bitstream if both the @code{mixing_level} 252option and the @code{room_type} option have the default values. 253@table @option 254@item 0 255@itemx notindicated 256Not Indicated (default) 257@item 1 258@itemx large 259Large Room 260@item 2 261@itemx small 262Small Room 263@end table 264 265@end table 266 267@subsubsection Other Metadata Options 268 269@table @option 270 271@item -copyright @var{boolean} 272Copyright Indicator. Specifies whether a copyright exists for this audio. 273@table @option 274@item 0 275@itemx off 276No Copyright Exists (default) 277@item 1 278@itemx on 279Copyright Exists 280@end table 281 282@item -dialnorm @var{value} 283Dialogue Normalization. Indicates how far the average dialogue level of the 284program is below digital 100% full scale (0 dBFS). This parameter determines a 285level shift during audio reproduction that sets the average volume of the 286dialogue to a preset level. The goal is to match volume level between program 287sources. A value of -31dB will result in no volume level change, relative to 288the source volume, during audio reproduction. Valid values are whole numbers in 289the range -31 to -1, with -31 being the default. 290 291@item -dsur_mode @var{mode} 292Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround 293(Pro Logic). This field will only be written to the bitstream if the audio 294stream is stereo. Using this option does @b{NOT} mean the encoder will actually 295apply Dolby Surround processing. 296@table @option 297@item 0 298@itemx notindicated 299Not Indicated (default) 300@item 1 301@itemx off 302Not Dolby Surround Encoded 303@item 2 304@itemx on 305Dolby Surround Encoded 306@end table 307 308@item -original @var{boolean} 309Original Bit Stream Indicator. Specifies whether this audio is from the 310original source and not a copy. 311@table @option 312@item 0 313@itemx off 314Not Original Source 315@item 1 316@itemx on 317Original Source (default) 318@end table 319 320@end table 321 322@subsection Extended Bitstream Information 323The extended bitstream options are part of the Alternate Bit Stream Syntax as 324specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts. 325If any one parameter in a group is specified, all values in that group will be 326written to the bitstream. Default values are used for those that are written 327but have not been specified. If the mixing levels are written, the decoder 328will use these values instead of the ones specified in the @code{center_mixlev} 329and @code{surround_mixlev} options if it supports the Alternate Bit Stream 330Syntax. 331 332@subsubsection Extended Bitstream Information - Part 1 333 334@table @option 335 336@item -dmix_mode @var{mode} 337Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt 338(Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode. 339@table @option 340@item 0 341@itemx notindicated 342Not Indicated (default) 343@item 1 344@itemx ltrt 345Lt/Rt Downmix Preferred 346@item 2 347@itemx loro 348Lo/Ro Downmix Preferred 349@end table 350 351@item -ltrt_cmixlev @var{level} 352Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the 353center channel when downmixing to stereo in Lt/Rt mode. 354@table @option 355@item 1.414 356Apply +3dB gain 357@item 1.189 358Apply +1.5dB gain 359@item 1.000 360Apply 0dB gain 361@item 0.841 362Apply -1.5dB gain 363@item 0.707 364Apply -3.0dB gain 365@item 0.595 366Apply -4.5dB gain (default) 367@item 0.500 368Apply -6.0dB gain 369@item 0.000 370Silence Center Channel 371@end table 372 373@item -ltrt_surmixlev @var{level} 374Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the 375surround channel(s) when downmixing to stereo in Lt/Rt mode. 376@table @option 377@item 0.841 378Apply -1.5dB gain 379@item 0.707 380Apply -3.0dB gain 381@item 0.595 382Apply -4.5dB gain 383@item 0.500 384Apply -6.0dB gain (default) 385@item 0.000 386Silence Surround Channel(s) 387@end table 388 389@item -loro_cmixlev @var{level} 390Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the 391center channel when downmixing to stereo in Lo/Ro mode. 392@table @option 393@item 1.414 394Apply +3dB gain 395@item 1.189 396Apply +1.5dB gain 397@item 1.000 398Apply 0dB gain 399@item 0.841 400Apply -1.5dB gain 401@item 0.707 402Apply -3.0dB gain 403@item 0.595 404Apply -4.5dB gain (default) 405@item 0.500 406Apply -6.0dB gain 407@item 0.000 408Silence Center Channel 409@end table 410 411@item -loro_surmixlev @var{level} 412Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the 413surround channel(s) when downmixing to stereo in Lo/Ro mode. 414@table @option 415@item 0.841 416Apply -1.5dB gain 417@item 0.707 418Apply -3.0dB gain 419@item 0.595 420Apply -4.5dB gain 421@item 0.500 422Apply -6.0dB gain (default) 423@item 0.000 424Silence Surround Channel(s) 425@end table 426 427@end table 428 429@subsubsection Extended Bitstream Information - Part 2 430 431@table @option 432 433@item -dsurex_mode @var{mode} 434Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX 435(7.1 matrixed to 5.1). Using this option does @b{NOT} mean the encoder will actually 436apply Dolby Surround EX processing. 437@table @option 438@item 0 439@itemx notindicated 440Not Indicated (default) 441@item 1 442@itemx on 443Dolby Surround EX Off 444@item 2 445@itemx off 446Dolby Surround EX On 447@end table 448 449@item -dheadphone_mode @var{mode} 450Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone 451encoding (multi-channel matrixed to 2.0 for use with headphones). Using this 452option does @b{NOT} mean the encoder will actually apply Dolby Headphone 453processing. 454@table @option 455@item 0 456@itemx notindicated 457Not Indicated (default) 458@item 1 459@itemx on 460Dolby Headphone Off 461@item 2 462@itemx off 463Dolby Headphone On 464@end table 465 466@item -ad_conv_type @var{type} 467A/D Converter Type. Indicates whether the audio has passed through HDCD A/D 468conversion. 469@table @option 470@item 0 471@itemx standard 472Standard A/D Converter (default) 473@item 1 474@itemx hdcd 475HDCD A/D Converter 476@end table 477 478@end table 479 480@subsection Other AC-3 Encoding Options 481 482@table @option 483 484@item -stereo_rematrixing @var{boolean} 485Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This 486is an optional AC-3 feature that increases quality by selectively encoding 487the left/right channels as mid/side. This option is enabled by default, and it 488is highly recommended that it be left as enabled except for testing purposes. 489 490@item cutoff @var{frequency} 491Set lowpass cutoff frequency. If unspecified, the encoder selects a default 492determined by various other encoding parameters. 493 494@end table 495 496@subsection Floating-Point-Only AC-3 Encoding Options 497 498These options are only valid for the floating-point encoder and do not exist 499for the fixed-point encoder due to the corresponding features not being 500implemented in fixed-point. 501 502@table @option 503 504@item -channel_coupling @var{boolean} 505Enables/Disables use of channel coupling, which is an optional AC-3 feature 506that increases quality by combining high frequency information from multiple 507channels into a single channel. The per-channel high frequency information is 508sent with less accuracy in both the frequency and time domains. This allows 509more bits to be used for lower frequencies while preserving enough information 510to reconstruct the high frequencies. This option is enabled by default for the 511floating-point encoder and should generally be left as enabled except for 512testing purposes or to increase encoding speed. 513@table @option 514@item -1 515@itemx auto 516Selected by Encoder (default) 517@item 0 518@itemx off 519Disable Channel Coupling 520@item 1 521@itemx on 522Enable Channel Coupling 523@end table 524 525@item -cpl_start_band @var{number} 526Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a 527value higher than the bandwidth is used, it will be reduced to 1 less than the 528coupling end band. If @var{auto} is used, the start band will be determined by 529the encoder based on the bit rate, sample rate, and channel layout. This option 530has no effect if channel coupling is disabled. 531@table @option 532@item -1 533@itemx auto 534Selected by Encoder (default) 535@end table 536 537@end table 538 539@anchor{flac} 540@section flac 541 542FLAC (Free Lossless Audio Codec) Encoder 543 544@subsection Options 545 546The following options are supported by FFmpeg's flac encoder. 547 548@table @option 549@item compression_level 550Sets the compression level, which chooses defaults for many other options 551if they are not set explicitly. Valid values are from 0 to 12, 5 is the 552default. 553 554@item frame_size 555Sets the size of the frames in samples per channel. 556 557@item lpc_coeff_precision 558Sets the LPC coefficient precision, valid values are from 1 to 15, 15 is the 559default. 560 561@item lpc_type 562Sets the first stage LPC algorithm 563@table @samp 564@item none 565LPC is not used 566 567@item fixed 568fixed LPC coefficients 569 570@item levinson 571 572@item cholesky 573@end table 574 575@item lpc_passes 576Number of passes to use for Cholesky factorization during LPC analysis 577 578@item min_partition_order 579The minimum partition order 580 581@item max_partition_order 582The maximum partition order 583 584@item prediction_order_method 585@table @samp 586@item estimation 587@item 2level 588@item 4level 589@item 8level 590@item search 591Bruteforce search 592@item log 593@end table 594 595@item ch_mode 596Channel mode 597@table @samp 598@item auto 599The mode is chosen automatically for each frame 600@item indep 601Channels are independently coded 602@item left_side 603@item right_side 604@item mid_side 605@end table 606 607@item exact_rice_parameters 608Chooses if rice parameters are calculated exactly or approximately. 609if set to 1 then they are chosen exactly, which slows the code down slightly and 610improves compression slightly. 611 612@item multi_dim_quant 613Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC algorithm is 614applied after the first stage to finetune the coefficients. This is quite slow 615and slightly improves compression. 616 617@end table 618 619@anchor{opusenc} 620@section opus 621 622Opus encoder. 623 624This is a native FFmpeg encoder for the Opus format. Currently its in development and 625only implements the CELT part of the codec. Its quality is usually worse and at best 626is equal to the libopus encoder. 627 628@subsection Options 629 630@table @option 631@item b 632Set bit rate in bits/s. If unspecified it uses the number of channels and the layout 633to make a good guess. 634 635@item opus_delay 636Sets the maximum delay in milliseconds. Lower delays than 20ms will very quickly 637decrease quality. 638@end table 639 640@anchor{libfdk-aac-enc} 641@section libfdk_aac 642 643libfdk-aac AAC (Advanced Audio Coding) encoder wrapper. 644 645The libfdk-aac library is based on the Fraunhofer FDK AAC code from 646the Android project. 647 648Requires the presence of the libfdk-aac headers and library during 649configuration. You need to explicitly configure the build with 650@code{--enable-libfdk-aac}. The library is also incompatible with GPL, 651so if you allow the use of GPL, you should configure with 652@code{--enable-gpl --enable-nonfree --enable-libfdk-aac}. 653 654This encoder is considered to produce output on par or worse at 128kbps to the 655@ref{aacenc,,the native FFmpeg AAC encoder} but can often produce better 656sounding audio at identical or lower bitrates and has support for the 657AAC-HE profiles. 658 659VBR encoding, enabled through the @option{vbr} or @option{flags 660+qscale} options, is experimental and only works with some 661combinations of parameters. 662 663Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or 664higher. 665 666For more information see the fdk-aac project at 667@url{http://sourceforge.net/p/opencore-amr/fdk-aac/}. 668 669@subsection Options 670 671The following options are mapped on the shared FFmpeg codec options. 672 673@table @option 674@item b 675Set bit rate in bits/s. If the bitrate is not explicitly specified, it 676is automatically set to a suitable value depending on the selected 677profile. 678 679In case VBR mode is enabled the option is ignored. 680 681@item ar 682Set audio sampling rate (in Hz). 683 684@item channels 685Set the number of audio channels. 686 687@item flags +qscale 688Enable fixed quality, VBR (Variable Bit Rate) mode. 689Note that VBR is implicitly enabled when the @option{vbr} value is 690positive. 691 692@item cutoff 693Set cutoff frequency. If not specified (or explicitly set to 0) it 694will use a value automatically computed by the library. Default value 695is 0. 696 697@item profile 698Set audio profile. 699 700The following profiles are recognized: 701@table @samp 702@item aac_low 703Low Complexity AAC (LC) 704 705@item aac_he 706High Efficiency AAC (HE-AAC) 707 708@item aac_he_v2 709High Efficiency AAC version 2 (HE-AACv2) 710 711@item aac_ld 712Low Delay AAC (LD) 713 714@item aac_eld 715Enhanced Low Delay AAC (ELD) 716@end table 717 718If not specified it is set to @samp{aac_low}. 719@end table 720 721The following are private options of the libfdk_aac encoder. 722 723@table @option 724@item afterburner 725Enable afterburner feature if set to 1, disabled if set to 0. This 726improves the quality but also the required processing power. 727 728Default value is 1. 729 730@item eld_sbr 731Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled 732if set to 0. 733 734Default value is 0. 735 736@item eld_v2 737Enable ELDv2 (LD-MPS extension for ELD stereo signals) for ELDv2 if set to 1, 738disabled if set to 0. 739 740Note that option is available when fdk-aac version (AACENCODER_LIB_VL0.AACENCODER_LIB_VL1.AACENCODER_LIB_VL2) > (4.0.0). 741 742Default value is 0. 743 744@item signaling 745Set SBR/PS signaling style. 746 747It can assume one of the following values: 748@table @samp 749@item default 750choose signaling implicitly (explicit hierarchical by default, 751implicit if global header is disabled) 752 753@item implicit 754implicit backwards compatible signaling 755 756@item explicit_sbr 757explicit SBR, implicit PS signaling 758 759@item explicit_hierarchical 760explicit hierarchical signaling 761@end table 762 763Default value is @samp{default}. 764 765@item latm 766Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0. 767 768Default value is 0. 769 770@item header_period 771Set StreamMuxConfig and PCE repetition period (in frames) for sending 772in-band configuration buffers within LATM/LOAS transport layer. 773 774Must be a 16-bits non-negative integer. 775 776Default value is 0. 777 778@item vbr 779Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty 780good) and 5 is highest quality. A value of 0 will disable VBR, and CBR 781(Constant Bit Rate) is enabled. 782 783Currently only the @samp{aac_low} profile supports VBR encoding. 784 785VBR modes 1-5 correspond to roughly the following average bit rates: 786 787@table @samp 788@item 1 78932 kbps/channel 790@item 2 79140 kbps/channel 792@item 3 79348-56 kbps/channel 794@item 4 79564 kbps/channel 796@item 5 797about 80-96 kbps/channel 798@end table 799 800Default value is 0. 801@end table 802 803@subsection Examples 804 805@itemize 806@item 807Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4) 808container: 809@example 810ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a 811@end example 812 813@item 814Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the 815High-Efficiency AAC profile: 816@example 817ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a 818@end example 819@end itemize 820 821@anchor{libmp3lame} 822@section libmp3lame 823 824LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper. 825 826Requires the presence of the libmp3lame headers and library during 827configuration. You need to explicitly configure the build with 828@code{--enable-libmp3lame}. 829 830See @ref{libshine} for a fixed-point MP3 encoder, although with a 831lower quality. 832 833@subsection Options 834 835The following options are supported by the libmp3lame wrapper. The 836@command{lame}-equivalent of the options are listed in parentheses. 837 838@table @option 839@item b (@emph{-b}) 840Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is 841expressed in kilobits/s. 842 843@item q (@emph{-V}) 844Set constant quality setting for VBR. This option is valid only 845using the @command{ffmpeg} command-line tool. For library interface 846users, use @option{global_quality}. 847 848@item compression_level (@emph{-q}) 849Set algorithm quality. Valid arguments are integers in the 0-9 range, 850with 0 meaning highest quality but slowest, and 9 meaning fastest 851while producing the worst quality. 852 853@item cutoff (@emph{--lowpass}) 854Set lowpass cutoff frequency. If unspecified, the encoder dynamically 855adjusts the cutoff. 856 857@item reservoir 858Enable use of bit reservoir when set to 1. Default value is 1. LAME 859has this enabled by default, but can be overridden by use 860@option{--nores} option. 861 862@item joint_stereo (@emph{-m j}) 863Enable the encoder to use (on a frame by frame basis) either L/R 864stereo or mid/side stereo. Default value is 1. 865 866@item abr (@emph{--abr}) 867Enable the encoder to use ABR when set to 1. The @command{lame} 868@option{--abr} sets the target bitrate, while this options only 869tells FFmpeg to use ABR still relies on @option{b} to set bitrate. 870 871@end table 872 873@section libopencore-amrnb 874 875OpenCORE Adaptive Multi-Rate Narrowband encoder. 876 877Requires the presence of the libopencore-amrnb headers and library during 878configuration. You need to explicitly configure the build with 879@code{--enable-libopencore-amrnb --enable-version3}. 880 881This is a mono-only encoder. Officially it only supports 8000Hz sample rate, 882but you can override it by setting @option{strict} to @samp{unofficial} or 883lower. 884 885@subsection Options 886 887@table @option 888 889@item b 890Set bitrate in bits per second. Only the following bitrates are supported, 891otherwise libavcodec will round to the nearest valid bitrate. 892 893@table @option 894@item 4750 895@item 5150 896@item 5900 897@item 6700 898@item 7400 899@item 7950 900@item 10200 901@item 12200 902@end table 903 904@item dtx 905Allow discontinuous transmission (generate comfort noise) when set to 1. The 906default value is 0 (disabled). 907 908@end table 909 910@section libopus 911 912libopus Opus Interactive Audio Codec encoder wrapper. 913 914Requires the presence of the libopus headers and library during 915configuration. You need to explicitly configure the build with 916@code{--enable-libopus}. 917 918@subsection Option Mapping 919 920Most libopus options are modelled after the @command{opusenc} utility from 921opus-tools. The following is an option mapping chart describing options 922supported by the libopus wrapper, and their @command{opusenc}-equivalent 923in parentheses. 924 925@table @option 926 927@item b (@emph{bitrate}) 928Set the bit rate in bits/s. FFmpeg's @option{b} option is 929expressed in bits/s, while @command{opusenc}'s @option{bitrate} in 930kilobits/s. 931 932@item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr}) 933Set VBR mode. The FFmpeg @option{vbr} option has the following 934valid arguments, with the @command{opusenc} equivalent options 935in parentheses: 936 937@table @samp 938@item off (@emph{hard-cbr}) 939Use constant bit rate encoding. 940 941@item on (@emph{vbr}) 942Use variable bit rate encoding (the default). 943 944@item constrained (@emph{cvbr}) 945Use constrained variable bit rate encoding. 946@end table 947 948@item compression_level (@emph{comp}) 949Set encoding algorithm complexity. Valid options are integers in 950the 0-10 range. 0 gives the fastest encodes but lower quality, while 10 951gives the highest quality but slowest encoding. The default is 10. 952 953@item frame_duration (@emph{framesize}) 954Set maximum frame size, or duration of a frame in milliseconds. The 955argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller 956frame sizes achieve lower latency but less quality at a given bitrate. 957Sizes greater than 20ms are only interesting at fairly low bitrates. 958The default is 20ms. 959 960@item packet_loss (@emph{expect-loss}) 961Set expected packet loss percentage. The default is 0. 962 963@item application (N.A.) 964Set intended application type. Valid options are listed below: 965 966@table @samp 967@item voip 968Favor improved speech intelligibility. 969@item audio 970Favor faithfulness to the input (the default). 971@item lowdelay 972Restrict to only the lowest delay modes. 973@end table 974 975@item cutoff (N.A.) 976Set cutoff bandwidth in Hz. The argument must be exactly one of the 977following: 4000, 6000, 8000, 12000, or 20000, corresponding to 978narrowband, mediumband, wideband, super wideband, and fullband 979respectively. The default is 0 (cutoff disabled). 980 981@item mapping_family (@emph{mapping_family}) 982Set channel mapping family to be used by the encoder. The default value of -1 983uses mapping family 0 for mono and stereo inputs, and mapping family 1 984otherwise. The default also disables the surround masking and LFE bandwidth 985optimzations in libopus, and requires that the input contains 8 channels or 986fewer. 987 988Other values include 0 for mono and stereo, 1 for surround sound with masking 989and LFE bandwidth optimizations, and 255 for independent streams with an 990unspecified channel layout. 991 992@item apply_phase_inv (N.A.) (requires libopus >= 1.2) 993If set to 0, disables the use of phase inversion for intensity stereo, 994improving the quality of mono downmixes, but slightly reducing normal stereo 995quality. The default is 1 (phase inversion enabled). 996 997@end table 998 999@anchor{libshine} 1000@section libshine 1001 1002Shine Fixed-Point MP3 encoder wrapper. 1003 1004Shine is a fixed-point MP3 encoder. It has a far better performance on 1005platforms without an FPU, e.g. armel CPUs, and some phones and tablets. 1006However, as it is more targeted on performance than quality, it is not on par 1007with LAME and other production-grade encoders quality-wise. Also, according to 1008the project's homepage, this encoder may not be free of bugs as the code was 1009written a long time ago and the project was dead for at least 5 years. 1010 1011This encoder only supports stereo and mono input. This is also CBR-only. 1012 1013The original project (last updated in early 2007) is at 1014@url{http://sourceforge.net/projects/libshine-fxp/}. We only support the 1015updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}. 1016 1017Requires the presence of the libshine headers and library during 1018configuration. You need to explicitly configure the build with 1019@code{--enable-libshine}. 1020 1021See also @ref{libmp3lame}. 1022 1023@subsection Options 1024 1025The following options are supported by the libshine wrapper. The 1026@command{shineenc}-equivalent of the options are listed in parentheses. 1027 1028@table @option 1029@item b (@emph{-b}) 1030Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option 1031is expressed in kilobits/s. 1032 1033@end table 1034 1035@section libtwolame 1036 1037TwoLAME MP2 encoder wrapper. 1038 1039Requires the presence of the libtwolame headers and library during 1040configuration. You need to explicitly configure the build with 1041@code{--enable-libtwolame}. 1042 1043@subsection Options 1044 1045The following options are supported by the libtwolame wrapper. The 1046@command{twolame}-equivalent options follow the FFmpeg ones and are in 1047parentheses. 1048 1049@table @option 1050@item b (@emph{-b}) 1051Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b} 1052option is expressed in kilobits/s. Default value is 128k. 1053 1054@item q (@emph{-V}) 1055Set quality for experimental VBR support. Maximum value range is 1056from -50 to 50, useful range is from -10 to 10. The higher the 1057value, the better the quality. This option is valid only using the 1058@command{ffmpeg} command-line tool. For library interface users, 1059use @option{global_quality}. 1060 1061@item mode (@emph{--mode}) 1062Set the mode of the resulting audio. Possible values: 1063 1064@table @samp 1065@item auto 1066Choose mode automatically based on the input. This is the default. 1067@item stereo 1068Stereo 1069@item joint_stereo 1070Joint stereo 1071@item dual_channel 1072Dual channel 1073@item mono 1074Mono 1075@end table 1076 1077@item psymodel (@emph{--psyc-mode}) 1078Set psychoacoustic model to use in encoding. The argument must be 1079an integer between -1 and 4, inclusive. The higher the value, the 1080better the quality. The default value is 3. 1081 1082@item energy_levels (@emph{--energy}) 1083Enable energy levels extensions when set to 1. The default value is 10840 (disabled). 1085 1086@item error_protection (@emph{--protect}) 1087Enable CRC error protection when set to 1. The default value is 0 1088(disabled). 1089 1090@item copyright (@emph{--copyright}) 1091Set MPEG audio copyright flag when set to 1. The default value is 0 1092(disabled). 1093 1094@item original (@emph{--original}) 1095Set MPEG audio original flag when set to 1. The default value is 0 1096(disabled). 1097 1098@end table 1099 1100@section libvo-amrwbenc 1101 1102VisualOn Adaptive Multi-Rate Wideband encoder. 1103 1104Requires the presence of the libvo-amrwbenc headers and library during 1105configuration. You need to explicitly configure the build with 1106@code{--enable-libvo-amrwbenc --enable-version3}. 1107 1108This is a mono-only encoder. Officially it only supports 16000Hz sample 1109rate, but you can override it by setting @option{strict} to 1110@samp{unofficial} or lower. 1111 1112@subsection Options 1113 1114@table @option 1115 1116@item b 1117Set bitrate in bits/s. Only the following bitrates are supported, otherwise 1118libavcodec will round to the nearest valid bitrate. 1119 1120@table @samp 1121@item 6600 1122@item 8850 1123@item 12650 1124@item 14250 1125@item 15850 1126@item 18250 1127@item 19850 1128@item 23050 1129@item 23850 1130@end table 1131 1132@item dtx 1133Allow discontinuous transmission (generate comfort noise) when set to 1. The 1134default value is 0 (disabled). 1135 1136@end table 1137 1138@section libvorbis 1139 1140libvorbis encoder wrapper. 1141 1142Requires the presence of the libvorbisenc headers and library during 1143configuration. You need to explicitly configure the build with 1144@code{--enable-libvorbis}. 1145 1146@subsection Options 1147 1148The following options are supported by the libvorbis wrapper. The 1149@command{oggenc}-equivalent of the options are listed in parentheses. 1150 1151To get a more accurate and extensive documentation of the libvorbis 1152options, consult the libvorbisenc's and @command{oggenc}'s documentations. 1153See @url{http://xiph.org/vorbis/}, 1154@url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1). 1155 1156@table @option 1157@item b (@emph{-b}) 1158Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is 1159expressed in kilobits/s. 1160 1161@item q (@emph{-q}) 1162Set constant quality setting for VBR. The value should be a float 1163number in the range of -1.0 to 10.0. The higher the value, the better 1164the quality. The default value is @samp{3.0}. 1165 1166This option is valid only using the @command{ffmpeg} command-line tool. 1167For library interface users, use @option{global_quality}. 1168 1169@item cutoff (@emph{--advanced-encode-option lowpass_frequency=N}) 1170Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s 1171related option is expressed in kHz. The default value is @samp{0} (cutoff 1172disabled). 1173 1174@item minrate (@emph{-m}) 1175Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is 1176expressed in kilobits/s. 1177 1178@item maxrate (@emph{-M}) 1179Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is 1180expressed in kilobits/s. This only has effect on ABR mode. 1181 1182@item iblock (@emph{--advanced-encode-option impulse_noisetune=N}) 1183Set noise floor bias for impulse blocks. The value is a float number from 1184-15.0 to 0.0. A negative bias instructs the encoder to pay special attention 1185to the crispness of transients in the encoded audio. The tradeoff for better 1186transient response is a higher bitrate. 1187 1188@end table 1189 1190@anchor{libwavpack} 1191@section libwavpack 1192 1193A wrapper providing WavPack encoding through libwavpack. 1194 1195Only lossless mode using 32-bit integer samples is supported currently. 1196 1197Requires the presence of the libwavpack headers and library during 1198configuration. You need to explicitly configure the build with 1199@code{--enable-libwavpack}. 1200 1201Note that a libavcodec-native encoder for the WavPack codec exists so users can 1202encode audios with this codec without using this encoder. See @ref{wavpackenc}. 1203 1204@subsection Options 1205 1206@command{wavpack} command line utility's corresponding options are listed in 1207parentheses, if any. 1208 1209@table @option 1210@item frame_size (@emph{--blocksize}) 1211Default is 32768. 1212 1213@item compression_level 1214Set speed vs. compression tradeoff. Acceptable arguments are listed below: 1215 1216@table @samp 1217@item 0 (@emph{-f}) 1218Fast mode. 1219 1220@item 1 1221Normal (default) settings. 1222 1223@item 2 (@emph{-h}) 1224High quality. 1225 1226@item 3 (@emph{-hh}) 1227Very high quality. 1228 1229@item 4-8 (@emph{-hh -x}@var{EXTRAPROC}) 1230Same as @samp{3}, but with extra processing enabled. 1231 1232@samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}. 1233 1234@end table 1235@end table 1236 1237@anchor{mjpegenc} 1238@section mjpeg 1239 1240Motion JPEG encoder. 1241 1242@subsection Options 1243 1244@table @option 1245@item huffman 1246Set the huffman encoding strategy. Possible values: 1247 1248@table @samp 1249@item default 1250Use the default huffman tables. This is the default strategy. 1251 1252@item optimal 1253Compute and use optimal huffman tables. 1254 1255@end table 1256@end table 1257 1258@anchor{wavpackenc} 1259@section wavpack 1260 1261WavPack lossless audio encoder. 1262 1263This is a libavcodec-native WavPack encoder. There is also an encoder based on 1264libwavpack, but there is virtually no reason to use that encoder. 1265 1266See also @ref{libwavpack}. 1267 1268@subsection Options 1269 1270The equivalent options for @command{wavpack} command line utility are listed in 1271parentheses. 1272 1273@subsubsection Shared options 1274 1275The following shared options are effective for this encoder. Only special notes 1276about this particular encoder will be documented here. For the general meaning 1277of the options, see @ref{codec-options,,the Codec Options chapter}. 1278 1279@table @option 1280@item frame_size (@emph{--blocksize}) 1281For this encoder, the range for this option is between 128 and 131072. Default 1282is automatically decided based on sample rate and number of channel. 1283 1284For the complete formula of calculating default, see 1285@file{libavcodec/wavpackenc.c}. 1286 1287@item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x}) 1288This option's syntax is consistent with @ref{libwavpack}'s. 1289@end table 1290 1291@subsubsection Private options 1292 1293@table @option 1294@item joint_stereo (@emph{-j}) 1295Set whether to enable joint stereo. Valid values are: 1296 1297@table @samp 1298@item on (@emph{1}) 1299Force mid/side audio encoding. 1300@item off (@emph{0}) 1301Force left/right audio encoding. 1302@item auto 1303Let the encoder decide automatically. 1304@end table 1305 1306@item optimize_mono 1307Set whether to enable optimization for mono. This option is only effective for 1308non-mono streams. Available values: 1309 1310@table @samp 1311@item on 1312enabled 1313@item off 1314disabled 1315@end table 1316 1317@end table 1318 1319@c man end AUDIO ENCODERS 1320 1321@chapter Video Encoders 1322@c man begin VIDEO ENCODERS 1323 1324A description of some of the currently available video encoders 1325follows. 1326 1327@section Hap 1328 1329Vidvox Hap video encoder. 1330 1331@subsection Options 1332 1333@table @option 1334@item format @var{integer} 1335Specifies the Hap format to encode. 1336 1337@table @option 1338@item hap 1339@item hap_alpha 1340@item hap_q 1341@end table 1342 1343Default value is @option{hap}. 1344 1345@item chunks @var{integer} 1346Specifies the number of chunks to split frames into, between 1 and 64. This 1347permits multithreaded decoding of large frames, potentially at the cost of 1348data-rate. The encoder may modify this value to divide frames evenly. 1349 1350Default value is @var{1}. 1351 1352@item compressor @var{integer} 1353Specifies the second-stage compressor to use. If set to @option{none}, 1354@option{chunks} will be limited to 1, as chunked uncompressed frames offer no 1355benefit. 1356 1357@table @option 1358@item none 1359@item snappy 1360@end table 1361 1362Default value is @option{snappy}. 1363 1364@end table 1365 1366@section jpeg2000 1367 1368The native jpeg 2000 encoder is lossy by default, the @code{-q:v} 1369option can be used to set the encoding quality. Lossless encoding 1370can be selected with @code{-pred 1}. 1371 1372@subsection Options 1373 1374@table @option 1375@item format 1376Can be set to either @code{j2k} or @code{jp2} (the default) that 1377makes it possible to store non-rgb pix_fmts. 1378 1379@end table 1380 1381@section librav1e 1382 1383rav1e AV1 encoder wrapper. 1384 1385Requires the presence of the rav1e headers and library during configuration. 1386You need to explicitly configure the build with @code{--enable-librav1e}. 1387 1388@subsection Options 1389 1390@table @option 1391@item qmax 1392Sets the maximum quantizer to use when using bitrate mode. 1393 1394@item qmin 1395Sets the minimum quantizer to use when using bitrate mode. 1396 1397@item qp 1398Uses quantizer mode to encode at the given quantizer (0-255). 1399 1400@item speed 1401Selects the speed preset (0-10) to encode with. 1402 1403@item tiles 1404Selects how many tiles to encode with. 1405 1406@item tile-rows 1407Selects how many rows of tiles to encode with. 1408 1409@item tile-columns 1410Selects how many columns of tiles to encode with. 1411 1412@item rav1e-params 1413Set rav1e options using a list of @var{key}=@var{value} pairs separated 1414by ":". See @command{rav1e --help} for a list of options. 1415 1416For example to specify librav1e encoding options with @option{-rav1e-params}: 1417 1418@example 1419ffmpeg -i input -c:v librav1e -b:v 500K -rav1e-params speed=5:low_latency=true output.mp4 1420@end example 1421 1422@end table 1423 1424@section libaom-av1 1425 1426libaom AV1 encoder wrapper. 1427 1428Requires the presence of the libaom headers and library during 1429configuration. You need to explicitly configure the build with 1430@code{--enable-libaom}. 1431 1432@subsection Options 1433 1434The wrapper supports the following standard libavcodec options: 1435 1436@table @option 1437 1438@item b 1439Set bitrate target in bits/second. By default this will use 1440variable-bitrate mode. If @option{maxrate} and @option{minrate} are 1441also set to the same value then it will use constant-bitrate mode, 1442otherwise if @option{crf} is set as well then it will use 1443constrained-quality mode. 1444 1445@item g keyint_min 1446Set key frame placement. The GOP size sets the maximum distance between 1447key frames; if zero the output stream will be intra-only. The minimum 1448distance is ignored unless it is the same as the GOP size, in which case 1449key frames will always appear at a fixed interval. Not set by default, 1450so without this option the library has completely free choice about 1451where to place key frames. 1452 1453@item qmin qmax 1454Set minimum/maximum quantisation values. Valid range is from 0 to 63 1455(warning: this does not match the quantiser values actually used by AV1 1456- divide by four to map real quantiser values to this range). Defaults 1457to min/max (no constraint). 1458 1459@item minrate maxrate bufsize rc_init_occupancy 1460Set rate control buffering parameters. Not used if not set - defaults 1461to unconstrained variable bitrate. 1462 1463@item threads 1464Set the number of threads to use while encoding. This may require the 1465@option{tiles} or @option{row-mt} options to also be set to actually 1466use the specified number of threads fully. Defaults to the number of 1467hardware threads supported by the host machine. 1468 1469@item profile 1470Set the encoding profile. Defaults to using the profile which matches 1471the bit depth and chroma subsampling of the input. 1472 1473@end table 1474 1475The wrapper also has some specific options: 1476 1477@table @option 1478 1479@item cpu-used 1480Set the quality/encoding speed tradeoff. Valid range is from 0 to 8, 1481higher numbers indicating greater speed and lower quality. The default 1482value is 1, which will be slow and high quality. 1483 1484@item auto-alt-ref 1485Enable use of alternate reference frames. Defaults to the internal 1486default of the library. 1487 1488@item arnr-max-frames (@emph{frames}) 1489Set altref noise reduction max frame count. Default is -1. 1490 1491@item arnr-strength (@emph{strength}) 1492Set altref noise reduction filter strength. Range is -1 to 6. Default is -1. 1493 1494@item aq-mode (@emph{aq-mode}) 1495Set adaptive quantization mode. Possible values: 1496 1497@table @samp 1498@item none (@emph{0}) 1499Disabled. 1500 1501@item variance (@emph{1}) 1502Variance-based. 1503 1504@item complexity (@emph{2}) 1505Complexity-based. 1506 1507@item cyclic (@emph{3}) 1508Cyclic refresh. 1509@end table 1510 1511@item lag-in-frames 1512Set the maximum number of frames which the encoder may keep in flight 1513at any one time for lookahead purposes. Defaults to the internal 1514default of the library. 1515 1516@item error-resilience 1517Enable error resilience features: 1518@table @option 1519@item default 1520Improve resilience against losses of whole frames. 1521@end table 1522Not enabled by default. 1523 1524@item crf 1525Set the quality/size tradeoff for constant-quality (no bitrate target) 1526and constrained-quality (with maximum bitrate target) modes. Valid 1527range is 0 to 63, higher numbers indicating lower quality and smaller 1528output size. Only used if set; by default only the bitrate target is 1529used. 1530 1531@item static-thresh 1532Set a change threshold on blocks below which they will be skipped by 1533the encoder. Defined in arbitrary units as a nonnegative integer, 1534defaulting to zero (no blocks are skipped). 1535 1536@item drop-threshold 1537Set a threshold for dropping frames when close to rate control bounds. 1538Defined as a percentage of the target buffer - when the rate control 1539buffer falls below this percentage, frames will be dropped until it 1540has refilled above the threshold. Defaults to zero (no frames are 1541dropped). 1542 1543@item denoise-noise-level (@emph{level}) 1544Amount of noise to be removed for grain synthesis. Grain synthesis is disabled if 1545this option is not set or set to 0. 1546 1547@item denoise-block-size (@emph{pixels}) 1548Block size used for denoising for grain synthesis. If not set, AV1 codec 1549uses the default value of 32. 1550 1551@item undershoot-pct (@emph{pct}) 1552Set datarate undershoot (min) percentage of the target bitrate. Range is -1 to 100. 1553Default is -1. 1554 1555@item overshoot-pct (@emph{pct}) 1556Set datarate overshoot (max) percentage of the target bitrate. Range is -1 to 1000. 1557Default is -1. 1558 1559@item minsection-pct (@emph{pct}) 1560Minimum percentage variation of the GOP bitrate from the target bitrate. If minsection-pct 1561is not set, the libaomenc wrapper computes it as follows: @code{(minrate * 100 / bitrate)}. 1562Range is -1 to 100. Default is -1 (unset). 1563 1564@item maxsection-pct (@emph{pct}) 1565Maximum percentage variation of the GOP bitrate from the target bitrate. If maxsection-pct 1566is not set, the libaomenc wrapper computes it as follows: @code{(maxrate * 100 / bitrate)}. 1567Range is -1 to 5000. Default is -1 (unset). 1568 1569@item frame-parallel (@emph{boolean}) 1570Enable frame parallel decodability features. Default is true. 1571 1572@item tiles 1573Set the number of tiles to encode the input video with, as columns x 1574rows. Larger numbers allow greater parallelism in both encoding and 1575decoding, but may decrease coding efficiency. Defaults to the minimum 1576number of tiles required by the size of the input video (this is 1x1 1577(that is, a single tile) for sizes up to and including 4K). 1578 1579@item tile-columns tile-rows 1580Set the number of tiles as log2 of the number of tile rows and columns. 1581Provided for compatibility with libvpx/VP9. 1582 1583@item row-mt (Requires libaom >= 1.0.0-759-g90a15f4f2) 1584Enable row based multi-threading. Disabled by default. 1585 1586@item enable-cdef (@emph{boolean}) 1587Enable Constrained Directional Enhancement Filter. The libaom-av1 1588encoder enables CDEF by default. 1589 1590@item enable-restoration (@emph{boolean}) 1591Enable Loop Restoration Filter. Default is true for libaom-av1. 1592 1593@item enable-global-motion (@emph{boolean}) 1594Enable the use of global motion for block prediction. Default is true. 1595 1596@item enable-intrabc (@emph{boolean}) 1597Enable block copy mode for intra block prediction. This mode is 1598useful for screen content. Default is true. 1599 1600@end table 1601 1602@section libkvazaar 1603 1604Kvazaar H.265/HEVC encoder. 1605 1606Requires the presence of the libkvazaar headers and library during 1607configuration. You need to explicitly configure the build with 1608@option{--enable-libkvazaar}. 1609 1610@subsection Options 1611 1612@table @option 1613 1614@item b 1615Set target video bitrate in bit/s and enable rate control. 1616 1617@item kvazaar-params 1618Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated 1619by commas (,). See kvazaar documentation for a list of options. 1620 1621@end table 1622 1623@section libopenh264 1624 1625Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper. 1626 1627This encoder requires the presence of the libopenh264 headers and 1628library during configuration. You need to explicitly configure the 1629build with @code{--enable-libopenh264}. The library is detected using 1630@command{pkg-config}. 1631 1632For more information about the library see 1633@url{http://www.openh264.org}. 1634 1635@subsection Options 1636 1637The following FFmpeg global options affect the configurations of the 1638libopenh264 encoder. 1639 1640@table @option 1641@item b 1642Set the bitrate (as a number of bits per second). 1643 1644@item g 1645Set the GOP size. 1646 1647@item maxrate 1648Set the max bitrate (as a number of bits per second). 1649 1650@item flags +global_header 1651Set global header in the bitstream. 1652 1653@item slices 1654Set the number of slices, used in parallelized encoding. Default value 1655is 0. This is only used when @option{slice_mode} is set to 1656@samp{fixed}. 1657 1658@item slice_mode 1659Set slice mode. Can assume one of the following possible values: 1660 1661@table @samp 1662@item fixed 1663a fixed number of slices 1664@item rowmb 1665one slice per row of macroblocks 1666@item auto 1667automatic number of slices according to number of threads 1668@item dyn 1669dynamic slicing 1670@end table 1671 1672Default value is @samp{auto}. 1673 1674@item loopfilter 1675Enable loop filter, if set to 1 (automatically enabled). To disable 1676set a value of 0. 1677 1678@item profile 1679Set profile restrictions. If set to the value of @samp{main} enable 1680CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1). 1681 1682@item max_nal_size 1683Set maximum NAL size in bytes. 1684 1685@item allow_skip_frames 1686Allow skipping frames to hit the target bitrate if set to 1. 1687@end table 1688 1689@section libtheora 1690 1691libtheora Theora encoder wrapper. 1692 1693Requires the presence of the libtheora headers and library during 1694configuration. You need to explicitly configure the build with 1695@code{--enable-libtheora}. 1696 1697For more information about the libtheora project see 1698@url{http://www.theora.org/}. 1699 1700@subsection Options 1701 1702The following global options are mapped to internal libtheora options 1703which affect the quality and the bitrate of the encoded stream. 1704 1705@table @option 1706@item b 1707Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In 1708case VBR (Variable Bit Rate) mode is enabled this option is ignored. 1709 1710@item flags 1711Used to enable constant quality mode (VBR) encoding through the 1712@option{qscale} flag, and to enable the @code{pass1} and @code{pass2} 1713modes. 1714 1715@item g 1716Set the GOP size. 1717 1718@item global_quality 1719Set the global quality as an integer in lambda units. 1720 1721Only relevant when VBR mode is enabled with @code{flags +qscale}. The 1722value is converted to QP units by dividing it by @code{FF_QP2LAMBDA}, 1723clipped in the [0 - 10] range, and then multiplied by 6.3 to get a 1724value in the native libtheora range [0-63]. A higher value corresponds 1725to a higher quality. 1726 1727@item q 1728Enable VBR mode when set to a non-negative value, and set constant 1729quality value as a double floating point value in QP units. 1730 1731The value is clipped in the [0-10] range, and then multiplied by 6.3 1732to get a value in the native libtheora range [0-63]. 1733 1734This option is valid only using the @command{ffmpeg} command-line 1735tool. For library interface users, use @option{global_quality}. 1736@end table 1737 1738@subsection Examples 1739 1740@itemize 1741@item 1742Set maximum constant quality (VBR) encoding with @command{ffmpeg}: 1743@example 1744ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg 1745@end example 1746 1747@item 1748Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream: 1749@example 1750ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg 1751@end example 1752@end itemize 1753 1754@section libvpx 1755 1756VP8/VP9 format supported through libvpx. 1757 1758Requires the presence of the libvpx headers and library during configuration. 1759You need to explicitly configure the build with @code{--enable-libvpx}. 1760 1761@subsection Options 1762 1763The following options are supported by the libvpx wrapper. The 1764@command{vpxenc}-equivalent options or values are listed in parentheses 1765for easy migration. 1766 1767To reduce the duplication of documentation, only the private options 1768and some others requiring special attention are documented here. For 1769the documentation of the undocumented generic options, see 1770@ref{codec-options,,the Codec Options chapter}. 1771 1772To get more documentation of the libvpx options, invoke the command 1773@command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or 1774@command{vpxenc --help}. Further information is available in the libvpx API 1775documentation. 1776 1777@table @option 1778 1779@item b (@emph{target-bitrate}) 1780Set bitrate in bits/s. Note that FFmpeg's @option{b} option is 1781expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in 1782kilobits/s. 1783 1784@item g (@emph{kf-max-dist}) 1785 1786@item keyint_min (@emph{kf-min-dist}) 1787 1788@item qmin (@emph{min-q}) 1789 1790@item qmax (@emph{max-q}) 1791 1792@item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz}) 1793Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are 1794specified in milliseconds, the libvpx wrapper converts this value as follows: 1795@code{buf-sz = bufsize * 1000 / bitrate}, 1796@code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}. 1797 1798@item rc_init_occupancy (@emph{buf-initial-sz}) 1799Set number of bits which should be loaded into the rc buffer before decoding 1800starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx 1801wrapper converts this value as follows: 1802@code{rc_init_occupancy * 1000 / bitrate}. 1803 1804@item undershoot-pct 1805Set datarate undershoot (min) percentage of the target bitrate. 1806 1807@item overshoot-pct 1808Set datarate overshoot (max) percentage of the target bitrate. 1809 1810@item skip_threshold (@emph{drop-frame}) 1811 1812@item qcomp (@emph{bias-pct}) 1813 1814@item maxrate (@emph{maxsection-pct}) 1815Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a 1816percentage of the target bitrate, the libvpx wrapper converts this value as 1817follows: @code{(maxrate * 100 / bitrate)}. 1818 1819@item minrate (@emph{minsection-pct}) 1820Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a 1821percentage of the target bitrate, the libvpx wrapper converts this value as 1822follows: @code{(minrate * 100 / bitrate)}. 1823 1824@item minrate, maxrate, b @emph{end-usage=cbr} 1825@code{(minrate == maxrate == bitrate)}. 1826 1827@item crf (@emph{end-usage=cq}, @emph{cq-level}) 1828 1829@item tune (@emph{tune}) 1830@table @samp 1831@item psnr (@emph{psnr}) 1832@item ssim (@emph{ssim}) 1833@end table 1834 1835@item quality, deadline (@emph{deadline}) 1836@table @samp 1837@item best 1838Use best quality deadline. Poorly named and quite slow, this option should be 1839avoided as it may give worse quality output than good. 1840@item good 1841Use good quality deadline. This is a good trade-off between speed and quality 1842when used with the @option{cpu-used} option. 1843@item realtime 1844Use realtime quality deadline. 1845@end table 1846 1847@item speed, cpu-used (@emph{cpu-used}) 1848Set quality/speed ratio modifier. Higher values speed up the encode at the cost 1849of quality. 1850 1851@item nr (@emph{noise-sensitivity}) 1852 1853@item static-thresh 1854Set a change threshold on blocks below which they will be skipped by the 1855encoder. 1856 1857@item slices (@emph{token-parts}) 1858Note that FFmpeg's @option{slices} option gives the total number of partitions, 1859while @command{vpxenc}'s @option{token-parts} is given as 1860@code{log2(partitions)}. 1861 1862@item max-intra-rate 1863Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0 1864means unlimited. 1865 1866@item force_key_frames 1867@code{VPX_EFLAG_FORCE_KF} 1868 1869@item Alternate reference frame related 1870@table @option 1871@item auto-alt-ref 1872Enable use of alternate reference frames (2-pass only). 1873Values greater than 1 enable multi-layer alternate reference frames (VP9 only). 1874@item arnr-maxframes 1875Set altref noise reduction max frame count. 1876@item arnr-type 1877Set altref noise reduction filter type: backward, forward, centered. 1878@item arnr-strength 1879Set altref noise reduction filter strength. 1880@item rc-lookahead, lag-in-frames (@emph{lag-in-frames}) 1881Set number of frames to look ahead for frametype and ratecontrol. 1882@end table 1883 1884@item error-resilient 1885Enable error resiliency features. 1886 1887@item sharpness @var{integer} 1888Increase sharpness at the expense of lower PSNR. 1889The valid range is [0, 7]. 1890 1891@item ts-parameters 1892Sets the temporal scalability configuration using a :-separated list of 1893key=value pairs. For example, to specify temporal scalability parameters 1894with @code{ffmpeg}: 1895@example 1896ffmpeg -i INPUT -c:v libvpx -ts-parameters ts_number_layers=3:\ 1897ts_target_bitrate=250,500,1000:ts_rate_decimator=4,2,1:\ 1898ts_periodicity=4:ts_layer_id=0,2,1,2:ts_layering_mode=3 OUTPUT 1899@end example 1900Below is a brief explanation of each of the parameters, please 1901refer to @code{struct vpx_codec_enc_cfg} in @code{vpx/vpx_encoder.h} for more 1902details. 1903@table @option 1904@item ts_number_layers 1905Number of temporal coding layers. 1906@item ts_target_bitrate 1907Target bitrate for each temporal layer (in kbps). 1908(bitrate should be inclusive of the lower temporal layer). 1909@item ts_rate_decimator 1910Frame rate decimation factor for each temporal layer. 1911@item ts_periodicity 1912Length of the sequence defining frame temporal layer membership. 1913@item ts_layer_id 1914Template defining the membership of frames to temporal layers. 1915@item ts_layering_mode 1916(optional) Selecting the temporal structure from a set of pre-defined temporal layering modes. 1917Currently supports the following options. 1918@table @option 1919@item 0 1920No temporal layering flags are provided internally, 1921relies on flags being passed in using @code{metadata} field in @code{AVFrame} 1922with following keys. 1923@table @option 1924@item vp8-flags 1925Sets the flags passed into the encoder to indicate the referencing scheme for 1926the current frame. 1927Refer to function @code{vpx_codec_encode} in @code{vpx/vpx_encoder.h} for more 1928details. 1929@item temporal_id 1930Explicitly sets the temporal id of the current frame to encode. 1931@end table 1932@item 2 1933Two temporal layers. 0-1... 1934@item 3 1935Three temporal layers. 0-2-1-2...; with single reference frame. 1936@item 4 1937Same as option "3", except there is a dependency between 1938the two temporal layer 2 frames within the temporal period. 1939@end table 1940@end table 1941 1942@item VP9-specific options 1943@table @option 1944@item lossless 1945Enable lossless mode. 1946@item tile-columns 1947Set number of tile columns to use. Note this is given as 1948@code{log2(tile_columns)}. For example, 8 tile columns would be requested by 1949setting the @option{tile-columns} option to 3. 1950@item tile-rows 1951Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}. 1952For example, 4 tile rows would be requested by setting the @option{tile-rows} 1953option to 2. 1954@item frame-parallel 1955Enable frame parallel decodability features. 1956@item aq-mode 1957Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3: 1958cyclic refresh, 4: equator360). 1959@item colorspace @emph{color-space} 1960Set input color space. The VP9 bitstream supports signaling the following 1961colorspaces: 1962@table @option 1963@item @samp{rgb} @emph{sRGB} 1964@item @samp{bt709} @emph{bt709} 1965@item @samp{unspecified} @emph{unknown} 1966@item @samp{bt470bg} @emph{bt601} 1967@item @samp{smpte170m} @emph{smpte170} 1968@item @samp{smpte240m} @emph{smpte240} 1969@item @samp{bt2020_ncl} @emph{bt2020} 1970@end table 1971@item row-mt @var{boolean} 1972Enable row based multi-threading. 1973@item tune-content 1974Set content type: default (0), screen (1), film (2). 1975@item corpus-complexity 1976Corpus VBR mode is a variant of standard VBR where the complexity distribution 1977midpoint is passed in rather than calculated for a specific clip or chunk. 1978 1979The valid range is [0, 10000]. 0 (default) uses standard VBR. 1980@item enable-tpl @var{boolean} 1981Enable temporal dependency model. 1982@end table 1983 1984@end table 1985 1986For more information about libvpx see: 1987@url{http://www.webmproject.org/} 1988 1989@section libwebp 1990 1991libwebp WebP Image encoder wrapper 1992 1993libwebp is Google's official encoder for WebP images. It can encode in either 1994lossy or lossless mode. Lossy images are essentially a wrapper around a VP8 1995frame. Lossless images are a separate codec developed by Google. 1996 1997@subsection Pixel Format 1998 1999Currently, libwebp only supports YUV420 for lossy and RGB for lossless due 2000to limitations of the format and libwebp. Alpha is supported for either mode. 2001Because of API limitations, if RGB is passed in when encoding lossy or YUV is 2002passed in for encoding lossless, the pixel format will automatically be 2003converted using functions from libwebp. This is not ideal and is done only for 2004convenience. 2005 2006@subsection Options 2007 2008@table @option 2009 2010@item -lossless @var{boolean} 2011Enables/Disables use of lossless mode. Default is 0. 2012 2013@item -compression_level @var{integer} 2014For lossy, this is a quality/speed tradeoff. Higher values give better quality 2015for a given size at the cost of increased encoding time. For lossless, this is 2016a size/speed tradeoff. Higher values give smaller size at the cost of increased 2017encoding time. More specifically, it controls the number of extra algorithms 2018and compression tools used, and varies the combination of these tools. This 2019maps to the @var{method} option in libwebp. The valid range is 0 to 6. 2020Default is 4. 2021 2022@item -qscale @var{float} 2023For lossy encoding, this controls image quality, 0 to 100. For lossless 2024encoding, this controls the effort and time spent at compressing more. The 2025default value is 75. Note that for usage via libavcodec, this option is called 2026@var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}. 2027 2028@item -preset @var{type} 2029Configuration preset. This does some automatic settings based on the general 2030type of the image. 2031@table @option 2032@item none 2033Do not use a preset. 2034@item default 2035Use the encoder default. 2036@item picture 2037Digital picture, like portrait, inner shot 2038@item photo 2039Outdoor photograph, with natural lighting 2040@item drawing 2041Hand or line drawing, with high-contrast details 2042@item icon 2043Small-sized colorful images 2044@item text 2045Text-like 2046@end table 2047 2048@end table 2049 2050@section libx264, libx264rgb 2051 2052x264 H.264/MPEG-4 AVC encoder wrapper. 2053 2054This encoder requires the presence of the libx264 headers and library 2055during configuration. You need to explicitly configure the build with 2056@code{--enable-libx264}. 2057 2058libx264 supports an impressive number of features, including 8x8 and 20594x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC 2060entropy coding, interlacing (MBAFF), lossless mode, psy optimizations 2061for detail retention (adaptive quantization, psy-RD, psy-trellis). 2062 2063Many libx264 encoder options are mapped to FFmpeg global codec 2064options, while unique encoder options are provided through private 2065options. Additionally the @option{x264opts} and @option{x264-params} 2066private options allows one to pass a list of key=value tuples as accepted 2067by the libx264 @code{x264_param_parse} function. 2068 2069The x264 project website is at 2070@url{http://www.videolan.org/developers/x264.html}. 2071 2072The libx264rgb encoder is the same as libx264, except it accepts packed RGB 2073pixel formats as input instead of YUV. 2074 2075@subsection Supported Pixel Formats 2076 2077x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at 2078x264's configure time. FFmpeg only supports one bit depth in one particular 2079build. In other words, it is not possible to build one FFmpeg with multiple 2080versions of x264 with different bit depths. 2081 2082@subsection Options 2083 2084The following options are supported by the libx264 wrapper. The 2085@command{x264}-equivalent options or values are listed in parentheses 2086for easy migration. 2087 2088To reduce the duplication of documentation, only the private options 2089and some others requiring special attention are documented here. For 2090the documentation of the undocumented generic options, see 2091@ref{codec-options,,the Codec Options chapter}. 2092 2093To get a more accurate and extensive documentation of the libx264 2094options, invoke the command @command{x264 --fullhelp} or consult 2095the libx264 documentation. 2096 2097@table @option 2098@item b (@emph{bitrate}) 2099Set bitrate in bits/s. Note that FFmpeg's @option{b} option is 2100expressed in bits/s, while @command{x264}'s @option{bitrate} is in 2101kilobits/s. 2102 2103@item bf (@emph{bframes}) 2104 2105@item g (@emph{keyint}) 2106 2107@item qmin (@emph{qpmin}) 2108Minimum quantizer scale. 2109 2110@item qmax (@emph{qpmax}) 2111Maximum quantizer scale. 2112 2113@item qdiff (@emph{qpstep}) 2114Maximum difference between quantizer scales. 2115 2116@item qblur (@emph{qblur}) 2117Quantizer curve blur 2118 2119@item qcomp (@emph{qcomp}) 2120Quantizer curve compression factor 2121 2122@item refs (@emph{ref}) 2123Number of reference frames each P-frame can use. The range is from @var{0-16}. 2124 2125@item sc_threshold (@emph{scenecut}) 2126Sets the threshold for the scene change detection. 2127 2128@item trellis (@emph{trellis}) 2129Performs Trellis quantization to increase efficiency. Enabled by default. 2130 2131@item nr (@emph{nr}) 2132 2133@item me_range (@emph{merange}) 2134Maximum range of the motion search in pixels. 2135 2136@item me_method (@emph{me}) 2137Set motion estimation method. Possible values in the decreasing order 2138of speed: 2139 2140@table @samp 2141@item dia (@emph{dia}) 2142@item epzs (@emph{dia}) 2143Diamond search with radius 1 (fastest). @samp{epzs} is an alias for 2144@samp{dia}. 2145@item hex (@emph{hex}) 2146Hexagonal search with radius 2. 2147@item umh (@emph{umh}) 2148Uneven multi-hexagon search. 2149@item esa (@emph{esa}) 2150Exhaustive search. 2151@item tesa (@emph{tesa}) 2152Hadamard exhaustive search (slowest). 2153@end table 2154 2155@item forced-idr 2156Normally, when forcing a I-frame type, the encoder can select any type 2157of I-frame. This option forces it to choose an IDR-frame. 2158 2159@item subq (@emph{subme}) 2160Sub-pixel motion estimation method. 2161 2162@item b_strategy (@emph{b-adapt}) 2163Adaptive B-frame placement decision algorithm. Use only on first-pass. 2164 2165@item keyint_min (@emph{min-keyint}) 2166Minimum GOP size. 2167 2168@item coder 2169Set entropy encoder. Possible values: 2170 2171@table @samp 2172@item ac 2173Enable CABAC. 2174 2175@item vlc 2176Enable CAVLC and disable CABAC. It generates the same effect as 2177@command{x264}'s @option{--no-cabac} option. 2178@end table 2179 2180@item cmp 2181Set full pixel motion estimation comparison algorithm. Possible values: 2182 2183@table @samp 2184@item chroma 2185Enable chroma in motion estimation. 2186 2187@item sad 2188Ignore chroma in motion estimation. It generates the same effect as 2189@command{x264}'s @option{--no-chroma-me} option. 2190@end table 2191 2192@item threads (@emph{threads}) 2193Number of encoding threads. 2194 2195@item thread_type 2196Set multithreading technique. Possible values: 2197 2198@table @samp 2199@item slice 2200Slice-based multithreading. It generates the same effect as 2201@command{x264}'s @option{--sliced-threads} option. 2202@item frame 2203Frame-based multithreading. 2204@end table 2205 2206@item flags 2207Set encoding flags. It can be used to disable closed GOP and enable 2208open GOP by setting it to @code{-cgop}. The result is similar to 2209the behavior of @command{x264}'s @option{--open-gop} option. 2210 2211@item rc_init_occupancy (@emph{vbv-init}) 2212 2213@item preset (@emph{preset}) 2214Set the encoding preset. 2215 2216@item tune (@emph{tune}) 2217Set tuning of the encoding params. 2218 2219@item profile (@emph{profile}) 2220Set profile restrictions. 2221 2222@item fastfirstpass 2223Enable fast settings when encoding first pass, when set to 1. When set 2224to 0, it has the same effect of @command{x264}'s 2225@option{--slow-firstpass} option. 2226 2227@item crf (@emph{crf}) 2228Set the quality for constant quality mode. 2229 2230@item crf_max (@emph{crf-max}) 2231In CRF mode, prevents VBV from lowering quality beyond this point. 2232 2233@item qp (@emph{qp}) 2234Set constant quantization rate control method parameter. 2235 2236@item aq-mode (@emph{aq-mode}) 2237Set AQ method. Possible values: 2238 2239@table @samp 2240@item none (@emph{0}) 2241Disabled. 2242 2243@item variance (@emph{1}) 2244Variance AQ (complexity mask). 2245 2246@item autovariance (@emph{2}) 2247Auto-variance AQ (experimental). 2248@end table 2249 2250@item aq-strength (@emph{aq-strength}) 2251Set AQ strength, reduce blocking and blurring in flat and textured areas. 2252 2253@item psy 2254Use psychovisual optimizations when set to 1. When set to 0, it has the 2255same effect as @command{x264}'s @option{--no-psy} option. 2256 2257@item psy-rd (@emph{psy-rd}) 2258Set strength of psychovisual optimization, in 2259@var{psy-rd}:@var{psy-trellis} format. 2260 2261@item rc-lookahead (@emph{rc-lookahead}) 2262Set number of frames to look ahead for frametype and ratecontrol. 2263 2264@item weightb 2265Enable weighted prediction for B-frames when set to 1. When set to 0, 2266it has the same effect as @command{x264}'s @option{--no-weightb} option. 2267 2268@item weightp (@emph{weightp}) 2269Set weighted prediction method for P-frames. Possible values: 2270 2271@table @samp 2272@item none (@emph{0}) 2273Disabled 2274@item simple (@emph{1}) 2275Enable only weighted refs 2276@item smart (@emph{2}) 2277Enable both weighted refs and duplicates 2278@end table 2279 2280@item ssim (@emph{ssim}) 2281Enable calculation and printing SSIM stats after the encoding. 2282 2283@item intra-refresh (@emph{intra-refresh}) 2284Enable the use of Periodic Intra Refresh instead of IDR frames when set 2285to 1. 2286 2287@item avcintra-class (@emph{class}) 2288Configure the encoder to generate AVC-Intra. 2289Valid values are 50,100 and 200 2290 2291@item bluray-compat (@emph{bluray-compat}) 2292Configure the encoder to be compatible with the bluray standard. 2293It is a shorthand for setting "bluray-compat=1 force-cfr=1". 2294 2295@item b-bias (@emph{b-bias}) 2296Set the influence on how often B-frames are used. 2297 2298@item b-pyramid (@emph{b-pyramid}) 2299Set method for keeping of some B-frames as references. Possible values: 2300 2301@table @samp 2302@item none (@emph{none}) 2303Disabled. 2304@item strict (@emph{strict}) 2305Strictly hierarchical pyramid. 2306@item normal (@emph{normal}) 2307Non-strict (not Blu-ray compatible). 2308@end table 2309 2310@item mixed-refs 2311Enable the use of one reference per partition, as opposed to one 2312reference per macroblock when set to 1. When set to 0, it has the 2313same effect as @command{x264}'s @option{--no-mixed-refs} option. 2314 2315@item 8x8dct 2316Enable adaptive spatial transform (high profile 8x8 transform) 2317when set to 1. When set to 0, it has the same effect as 2318@command{x264}'s @option{--no-8x8dct} option. 2319 2320@item fast-pskip 2321Enable early SKIP detection on P-frames when set to 1. When set 2322to 0, it has the same effect as @command{x264}'s 2323@option{--no-fast-pskip} option. 2324 2325@item aud (@emph{aud}) 2326Enable use of access unit delimiters when set to 1. 2327 2328@item mbtree 2329Enable use macroblock tree ratecontrol when set to 1. When set 2330to 0, it has the same effect as @command{x264}'s 2331@option{--no-mbtree} option. 2332 2333@item deblock (@emph{deblock}) 2334Set loop filter parameters, in @var{alpha}:@var{beta} form. 2335 2336@item cplxblur (@emph{cplxblur}) 2337Set fluctuations reduction in QP (before curve compression). 2338 2339@item partitions (@emph{partitions}) 2340Set partitions to consider as a comma-separated list of. Possible 2341values in the list: 2342 2343@table @samp 2344@item p8x8 23458x8 P-frame partition. 2346@item p4x4 23474x4 P-frame partition. 2348@item b8x8 23494x4 B-frame partition. 2350@item i8x8 23518x8 I-frame partition. 2352@item i4x4 23534x4 I-frame partition. 2354(Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling 2355@samp{i8x8} requires adaptive spatial transform (@option{8x8dct} 2356option) to be enabled.) 2357@item none (@emph{none}) 2358Do not consider any partitions. 2359@item all (@emph{all}) 2360Consider every partition. 2361@end table 2362 2363@item direct-pred (@emph{direct}) 2364Set direct MV prediction mode. Possible values: 2365 2366@table @samp 2367@item none (@emph{none}) 2368Disable MV prediction. 2369@item spatial (@emph{spatial}) 2370Enable spatial predicting. 2371@item temporal (@emph{temporal}) 2372Enable temporal predicting. 2373@item auto (@emph{auto}) 2374Automatically decided. 2375@end table 2376 2377@item slice-max-size (@emph{slice-max-size}) 2378Set the limit of the size of each slice in bytes. If not specified 2379but RTP payload size (@option{ps}) is specified, that is used. 2380 2381@item stats (@emph{stats}) 2382Set the file name for multi-pass stats. 2383 2384@item nal-hrd (@emph{nal-hrd}) 2385Set signal HRD information (requires @option{vbv-bufsize} to be set). 2386Possible values: 2387 2388@table @samp 2389@item none (@emph{none}) 2390Disable HRD information signaling. 2391@item vbr (@emph{vbr}) 2392Variable bit rate. 2393@item cbr (@emph{cbr}) 2394Constant bit rate (not allowed in MP4 container). 2395@end table 2396 2397@item x264opts (N.A.) 2398Set any x264 option, see @command{x264 --fullhelp} for a list. 2399 2400Argument is a list of @var{key}=@var{value} couples separated by 2401":". In @var{filter} and @var{psy-rd} options that use ":" as a separator 2402themselves, use "," instead. They accept it as well since long ago but this 2403is kept undocumented for some reason. 2404 2405For example to specify libx264 encoding options with @command{ffmpeg}: 2406@example 2407ffmpeg -i foo.mpg -c:v libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv 2408@end example 2409 2410@item a53cc @var{boolean} 2411Import closed captions (which must be ATSC compatible format) into output. 2412Only the mpeg2 and h264 decoders provide these. Default is 1 (on). 2413 2414@item x264-params (N.A.) 2415Override the x264 configuration using a :-separated list of key=value 2416parameters. 2417 2418This option is functionally the same as the @option{x264opts}, but is 2419duplicated for compatibility with the Libav fork. 2420 2421For example to specify libx264 encoding options with @command{ffmpeg}: 2422@example 2423ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\ 2424cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\ 2425no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT 2426@end example 2427@end table 2428 2429Encoding ffpresets for common usages are provided so they can be used with the 2430general presets system (e.g. passing the @option{pre} option). 2431 2432@section libx265 2433 2434x265 H.265/HEVC encoder wrapper. 2435 2436This encoder requires the presence of the libx265 headers and library 2437during configuration. You need to explicitly configure the build with 2438@option{--enable-libx265}. 2439 2440@subsection Options 2441 2442@table @option 2443@item b 2444Sets target video bitrate. 2445 2446@item bf 2447 2448@item g 2449Set the GOP size. 2450 2451@item keyint_min 2452Minimum GOP size. 2453 2454@item refs 2455Number of reference frames each P-frame can use. The range is from @var{1-16}. 2456 2457@item preset 2458Set the x265 preset. 2459 2460@item tune 2461Set the x265 tune parameter. 2462 2463@item profile 2464Set profile restrictions. 2465 2466@item crf 2467Set the quality for constant quality mode. 2468 2469@item qp 2470Set constant quantization rate control method parameter. 2471 2472@item qmin 2473Minimum quantizer scale. 2474 2475@item qmax 2476Maximum quantizer scale. 2477 2478@item qdiff 2479Maximum difference between quantizer scales. 2480 2481@item qblur 2482Quantizer curve blur 2483 2484@item qcomp 2485Quantizer curve compression factor 2486 2487@item i_qfactor 2488 2489@item b_qfactor 2490 2491@item forced-idr 2492Normally, when forcing a I-frame type, the encoder can select any type 2493of I-frame. This option forces it to choose an IDR-frame. 2494 2495@item x265-params 2496Set x265 options using a list of @var{key}=@var{value} couples separated 2497by ":". See @command{x265 --help} for a list of options. 2498 2499For example to specify libx265 encoding options with @option{-x265-params}: 2500 2501@example 2502ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4 2503@end example 2504@end table 2505 2506@section libxavs2 2507 2508xavs2 AVS2-P2/IEEE1857.4 encoder wrapper. 2509 2510This encoder requires the presence of the libxavs2 headers and library 2511during configuration. You need to explicitly configure the build with 2512@option{--enable-libxavs2}. 2513 2514The following standard libavcodec options are used: 2515@itemize 2516@item 2517@option{b} / @option{bit_rate} 2518@item 2519@option{g} / @option{gop_size} 2520@item 2521@option{bf} / @option{max_b_frames} 2522@end itemize 2523 2524The encoder also has its own specific options: 2525@subsection Options 2526 2527@table @option 2528@item lcu_row_threads 2529Set the number of parallel threads for rows from 1 to 8 (default 5). 2530 2531@item initial_qp 2532Set the xavs2 quantization parameter from 1 to 63 (default 34). This is 2533used to set the initial qp for the first frame. 2534 2535@item qp 2536Set the xavs2 quantization parameter from 1 to 63 (default 34). This is 2537used to set the qp value under constant-QP mode. 2538 2539@item max_qp 2540Set the max qp for rate control from 1 to 63 (default 55). 2541 2542@item min_qp 2543Set the min qp for rate control from 1 to 63 (default 20). 2544 2545@item speed_level 2546Set the Speed level from 0 to 9 (default 0). Higher is better but slower. 2547 2548@item log_level 2549Set the log level from -1 to 3 (default 0). -1: none, 0: error, 25501: warning, 2: info, 3: debug. 2551 2552@item xavs2-params 2553Set xavs2 options using a list of @var{key}=@var{value} couples separated 2554by ":". 2555 2556For example to specify libxavs2 encoding options with @option{-xavs2-params}: 2557 2558@example 2559ffmpeg -i input -c:v libxavs2 -xavs2-params RdoqLevel=0 output.avs2 2560@end example 2561@end table 2562 2563@section libxvid 2564 2565Xvid MPEG-4 Part 2 encoder wrapper. 2566 2567This encoder requires the presence of the libxvidcore headers and library 2568during configuration. You need to explicitly configure the build with 2569@code{--enable-libxvid --enable-gpl}. 2570 2571The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so 2572users can encode to this format without this library. 2573 2574@subsection Options 2575 2576The following options are supported by the libxvid wrapper. Some of 2577the following options are listed but are not documented, and 2578correspond to shared codec options. See @ref{codec-options,,the Codec 2579Options chapter} for their documentation. The other shared options 2580which are not listed have no effect for the libxvid encoder. 2581 2582@table @option 2583@item b 2584 2585@item g 2586 2587@item qmin 2588 2589@item qmax 2590 2591@item mpeg_quant 2592 2593@item threads 2594 2595@item bf 2596 2597@item b_qfactor 2598 2599@item b_qoffset 2600 2601@item flags 2602Set specific encoding flags. Possible values: 2603 2604@table @samp 2605 2606@item mv4 2607Use four motion vector by macroblock. 2608 2609@item aic 2610Enable high quality AC prediction. 2611 2612@item gray 2613Only encode grayscale. 2614 2615@item gmc 2616Enable the use of global motion compensation (GMC). 2617 2618@item qpel 2619Enable quarter-pixel motion compensation. 2620 2621@item cgop 2622Enable closed GOP. 2623 2624@item global_header 2625Place global headers in extradata instead of every keyframe. 2626 2627@end table 2628 2629@item trellis 2630 2631@item me_method 2632Set motion estimation method. Possible values in decreasing order of 2633speed and increasing order of quality: 2634 2635@table @samp 2636@item zero 2637Use no motion estimation (default). 2638 2639@item phods 2640@item x1 2641@item log 2642Enable advanced diamond zonal search for 16x16 blocks and half-pixel 2643refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for 2644@samp{phods}. 2645 2646@item epzs 2647Enable all of the things described above, plus advanced diamond zonal 2648search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion 2649estimation on chroma planes. 2650 2651@item full 2652Enable all of the things described above, plus extended 16x16 and 8x8 2653blocks search. 2654@end table 2655 2656@item mbd 2657Set macroblock decision algorithm. Possible values in the increasing 2658order of quality: 2659 2660@table @samp 2661@item simple 2662Use macroblock comparing function algorithm (default). 2663 2664@item bits 2665Enable rate distortion-based half pixel and quarter pixel refinement for 266616x16 blocks. 2667 2668@item rd 2669Enable all of the things described above, plus rate distortion-based 2670half pixel and quarter pixel refinement for 8x8 blocks, and rate 2671distortion-based search using square pattern. 2672@end table 2673 2674@item lumi_aq 2675Enable lumi masking adaptive quantization when set to 1. Default is 0 2676(disabled). 2677 2678@item variance_aq 2679Enable variance adaptive quantization when set to 1. Default is 0 2680(disabled). 2681 2682When combined with @option{lumi_aq}, the resulting quality will not 2683be better than any of the two specified individually. In other 2684words, the resulting quality will be the worse one of the two 2685effects. 2686 2687@item ssim 2688Set structural similarity (SSIM) displaying method. Possible values: 2689 2690@table @samp 2691@item off 2692Disable displaying of SSIM information. 2693 2694@item avg 2695Output average SSIM at the end of encoding to stdout. The format of 2696showing the average SSIM is: 2697 2698@example 2699Average SSIM: %f 2700@end example 2701 2702For users who are not familiar with C, %f means a float number, or 2703a decimal (e.g. 0.939232). 2704 2705@item frame 2706Output both per-frame SSIM data during encoding and average SSIM at 2707the end of encoding to stdout. The format of per-frame information 2708is: 2709 2710@example 2711 SSIM: avg: %1.3f min: %1.3f max: %1.3f 2712@end example 2713 2714For users who are not familiar with C, %1.3f means a float number 2715rounded to 3 digits after the dot (e.g. 0.932). 2716 2717@end table 2718 2719@item ssim_acc 2720Set SSIM accuracy. Valid options are integers within the range of 27210-4, while 0 gives the most accurate result and 4 computes the 2722fastest. 2723 2724@end table 2725 2726@section mpeg2 2727 2728MPEG-2 video encoder. 2729 2730@subsection Options 2731 2732@table @option 2733@item seq_disp_ext @var{integer} 2734Specifies if the encoder should write a sequence_display_extension to the 2735output. 2736@table @option 2737@item -1 2738@itemx auto 2739Decide automatically to write it or not (this is the default) by checking if 2740the data to be written is different from the default or unspecified values. 2741@item 0 2742@itemx never 2743Never write it. 2744@item 1 2745@itemx always 2746Always write it. 2747@end table 2748@item video_format @var{integer} 2749Specifies the video_format written into the sequence display extension 2750indicating the source of the video pictures. The default is @samp{unspecified}, 2751can be @samp{component}, @samp{pal}, @samp{ntsc}, @samp{secam} or @samp{mac}. 2752For maximum compatibility, use @samp{component}. 2753@item a53cc @var{boolean} 2754Import closed captions (which must be ATSC compatible format) into output. 2755Default is 1 (on). 2756@end table 2757 2758@section png 2759 2760PNG image encoder. 2761 2762@subsection Private options 2763 2764@table @option 2765@item dpi @var{integer} 2766Set physical density of pixels, in dots per inch, unset by default 2767@item dpm @var{integer} 2768Set physical density of pixels, in dots per meter, unset by default 2769@end table 2770 2771@section ProRes 2772 2773Apple ProRes encoder. 2774 2775FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder. 2776The used encoder can be chosen with the @code{-vcodec} option. 2777 2778@subsection Private Options for prores-ks 2779 2780@table @option 2781@item profile @var{integer} 2782Select the ProRes profile to encode 2783@table @samp 2784@item proxy 2785@item lt 2786@item standard 2787@item hq 2788@item 4444 2789@item 4444xq 2790@end table 2791 2792@item quant_mat @var{integer} 2793Select quantization matrix. 2794@table @samp 2795@item auto 2796@item default 2797@item proxy 2798@item lt 2799@item standard 2800@item hq 2801@end table 2802If set to @var{auto}, the matrix matching the profile will be picked. 2803If not set, the matrix providing the highest quality, @var{default}, will be 2804picked. 2805 2806@item bits_per_mb @var{integer} 2807How many bits to allot for coding one macroblock. Different profiles use 2808between 200 and 2400 bits per macroblock, the maximum is 8000. 2809 2810@item mbs_per_slice @var{integer} 2811Number of macroblocks in each slice (1-8); the default value (8) 2812should be good in almost all situations. 2813 2814@item vendor @var{string} 2815Override the 4-byte vendor ID. 2816A custom vendor ID like @var{apl0} would claim the stream was produced by 2817the Apple encoder. 2818 2819@item alpha_bits @var{integer} 2820Specify number of bits for alpha component. 2821Possible values are @var{0}, @var{8} and @var{16}. 2822Use @var{0} to disable alpha plane coding. 2823 2824@end table 2825 2826@subsection Speed considerations 2827 2828In the default mode of operation the encoder has to honor frame constraints 2829(i.e. not produce frames with size bigger than requested) while still making 2830output picture as good as possible. 2831A frame containing a lot of small details is harder to compress and the encoder 2832would spend more time searching for appropriate quantizers for each slice. 2833 2834Setting a higher @option{bits_per_mb} limit will improve the speed. 2835 2836For the fastest encoding speed set the @option{qscale} parameter (4 is the 2837recommended value) and do not set a size constraint. 2838 2839@section QSV encoders 2840 2841The family of Intel QuickSync Video encoders (MPEG-2, H.264, HEVC, JPEG/MJPEG and VP9) 2842 2843The ratecontrol method is selected as follows: 2844 2845@itemize @bullet 2846@item 2847When @option{global_quality} is specified, a quality-based mode is used. 2848Specifically this means either 2849@itemize @minus 2850@item 2851@var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is 2852also set (the @option{-qscale} ffmpeg option). 2853 2854@item 2855@var{LA_ICQ} - intelligent constant quality with lookahead, when the 2856@option{look_ahead} option is also set. 2857 2858@item 2859@var{ICQ} -- intelligent constant quality otherwise. 2860@end itemize 2861 2862@item 2863Otherwise, a bitrate-based mode is used. For all of those, you should specify at 2864least the desired average bitrate with the @option{b} option. 2865@itemize @minus 2866@item 2867@var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified. 2868 2869@item 2870@var{VCM} - video conferencing mode, when the @option{vcm} option is set. 2871 2872@item 2873@var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to 2874the average bitrate. 2875 2876@item 2877@var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher 2878than the average bitrate. 2879 2880@item 2881@var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode 2882is further configured by the @option{avbr_accuracy} and 2883@option{avbr_convergence} options. 2884@end itemize 2885@end itemize 2886 2887Note that depending on your system, a different mode than the one you specified 2888may be selected by the encoder. Set the verbosity level to @var{verbose} or 2889higher to see the actual settings used by the QSV runtime. 2890 2891Additional libavcodec global options are mapped to MSDK options as follows: 2892 2893@itemize 2894@item 2895@option{g/gop_size} -> @option{GopPicSize} 2896 2897@item 2898@option{bf/max_b_frames}+1 -> @option{GopRefDist} 2899 2900@item 2901@option{rc_init_occupancy/rc_initial_buffer_occupancy} -> 2902@option{InitialDelayInKB} 2903 2904@item 2905@option{slices} -> @option{NumSlice} 2906 2907@item 2908@option{refs} -> @option{NumRefFrame} 2909 2910@item 2911@option{b_strategy/b_frame_strategy} -> @option{BRefType} 2912 2913@item 2914@option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag} 2915 2916@item 2917For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and 2918@option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI}, 2919and @var{QPP} and @var{QPB} respectively. 2920 2921@item 2922Setting the @option{coder} option to the value @var{vlc} will make the H.264 2923encoder use CAVLC instead of CABAC. 2924 2925@end itemize 2926 2927@section snow 2928 2929@subsection Options 2930 2931@table @option 2932@item iterative_dia_size 2933dia size for the iterative motion estimation 2934@end table 2935 2936@section VAAPI encoders 2937 2938Wrappers for hardware encoders accessible via VAAPI. 2939 2940These encoders only accept input in VAAPI hardware surfaces. If you have input 2941in software frames, use the @option{hwupload} filter to upload them to the GPU. 2942 2943The following standard libavcodec options are used: 2944@itemize 2945@item 2946@option{g} / @option{gop_size} 2947@item 2948@option{bf} / @option{max_b_frames} 2949@item 2950@option{profile} 2951 2952If not set, this will be determined automatically from the format of the input 2953frames and the profiles supported by the driver. 2954@item 2955@option{level} 2956@item 2957@option{b} / @option{bit_rate} 2958@item 2959@option{maxrate} / @option{rc_max_rate} 2960@item 2961@option{bufsize} / @option{rc_buffer_size} 2962@item 2963@option{rc_init_occupancy} / @option{rc_initial_buffer_occupancy} 2964@item 2965@option{compression_level} 2966 2967Speed / quality tradeoff: higher values are faster / worse quality. 2968@item 2969@option{q} / @option{global_quality} 2970 2971Size / quality tradeoff: higher values are smaller / worse quality. 2972@item 2973@option{qmin} 2974@item 2975@option{qmax} 2976@item 2977@option{i_qfactor} / @option{i_quant_factor} 2978@item 2979@option{i_qoffset} / @option{i_quant_offset} 2980@item 2981@option{b_qfactor} / @option{b_quant_factor} 2982@item 2983@option{b_qoffset} / @option{b_quant_offset} 2984@item 2985@option{slices} 2986@end itemize 2987 2988All encoders support the following options: 2989@table @option 2990@item low_power 2991Some drivers/platforms offer a second encoder for some codecs intended to use 2992less power than the default encoder; setting this option will attempt to use 2993that encoder. Note that it may support a reduced feature set, so some other 2994options may not be available in this mode. 2995 2996@item idr_interval 2997Set the number of normal intra frames between full-refresh (IDR) frames in 2998open-GOP mode. The intra frames are still IRAPs, but will not include global 2999headers and may have non-decodable leading pictures. 3000 3001@item b_depth 3002Set the B-frame reference depth. When set to one (the default), all B-frames 3003will refer only to P- or I-frames. When set to greater values multiple layers 3004of B-frames will be present, frames in each layer only referring to frames in 3005higher layers. 3006 3007@item rc_mode 3008Set the rate control mode to use. A given driver may only support a subset of 3009modes. 3010 3011Possible modes: 3012@table @option 3013@item auto 3014Choose the mode automatically based on driver support and the other options. 3015This is the default. 3016@item CQP 3017Constant-quality. 3018@item CBR 3019Constant-bitrate. 3020@item VBR 3021Variable-bitrate. 3022@item ICQ 3023Intelligent constant-quality. 3024@item QVBR 3025Quality-defined variable-bitrate. 3026@item AVBR 3027Average variable bitrate. 3028@end table 3029 3030@end table 3031 3032Each encoder also has its own specific options: 3033@table @option 3034 3035@item h264_vaapi 3036@option{profile} sets the value of @emph{profile_idc} and the @emph{constraint_set*_flag}s. 3037@option{level} sets the value of @emph{level_idc}. 3038 3039@table @option 3040@item coder 3041Set entropy encoder (default is @emph{cabac}). Possible values: 3042 3043@table @samp 3044@item ac 3045@item cabac 3046Use CABAC. 3047 3048@item vlc 3049@item cavlc 3050Use CAVLC. 3051@end table 3052 3053@item aud 3054Include access unit delimiters in the stream (not included by default). 3055 3056@item sei 3057Set SEI message types to include. 3058Some combination of the following values: 3059@table @samp 3060@item identifier 3061Include a @emph{user_data_unregistered} message containing information about 3062the encoder. 3063@item timing 3064Include picture timing parameters (@emph{buffering_period} and 3065@emph{pic_timing} messages). 3066@item recovery_point 3067Include recovery points where appropriate (@emph{recovery_point} messages). 3068@end table 3069 3070@end table 3071 3072@item hevc_vaapi 3073@option{profile} and @option{level} set the values of 3074@emph{general_profile_idc} and @emph{general_level_idc} respectively. 3075 3076@table @option 3077@item aud 3078Include access unit delimiters in the stream (not included by default). 3079 3080@item tier 3081Set @emph{general_tier_flag}. This may affect the level chosen for the stream 3082if it is not explicitly specified. 3083 3084@item sei 3085Set SEI message types to include. 3086Some combination of the following values: 3087@table @samp 3088@item hdr 3089Include HDR metadata if the input frames have it 3090(@emph{mastering_display_colour_volume} and @emph{content_light_level} 3091messages). 3092@end table 3093 3094@end table 3095 3096@item mjpeg_vaapi 3097Only baseline DCT encoding is supported. The encoder always uses the standard 3098quantisation and huffman tables - @option{global_quality} scales the standard 3099quantisation table (range 1-100). 3100 3101For YUV, 4:2:0, 4:2:2 and 4:4:4 subsampling modes are supported. RGB is also 3102supported, and will create an RGB JPEG. 3103 3104@table @option 3105@item jfif 3106Include JFIF header in each frame (not included by default). 3107@item huffman 3108Include standard huffman tables (on by default). Turning this off will save 3109a few hundred bytes in each output frame, but may lose compatibility with some 3110JPEG decoders which don't fully handle MJPEG. 3111@end table 3112 3113@item mpeg2_vaapi 3114@option{profile} and @option{level} set the value of @emph{profile_and_level_indication}. 3115 3116@item vp8_vaapi 3117B-frames are not supported. 3118 3119@option{global_quality} sets the @emph{q_idx} used for non-key frames (range 0-127). 3120 3121@table @option 3122@item loop_filter_level 3123@item loop_filter_sharpness 3124Manually set the loop filter parameters. 3125@end table 3126 3127@item vp9_vaapi 3128@option{global_quality} sets the @emph{q_idx} used for P-frames (range 0-255). 3129 3130@table @option 3131@item loop_filter_level 3132@item loop_filter_sharpness 3133Manually set the loop filter parameters. 3134@end table 3135 3136B-frames are supported, but the output stream is always in encode order rather than display 3137order. If B-frames are enabled, it may be necessary to use the @option{vp9_raw_reorder} 3138bitstream filter to modify the output stream to display frames in the correct order. 3139 3140Only normal frames are produced - the @option{vp9_superframe} bitstream filter may be 3141required to produce a stream usable with all decoders. 3142 3143@end table 3144 3145@section vc2 3146 3147SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at 3148professional broadcasting but since it supports yuv420, yuv422 and yuv444 at 31498 (limited range or full range), 10 or 12 bits, this makes it suitable for 3150other tasks which require low overhead and low compression (like screen 3151recording). 3152 3153@subsection Options 3154 3155@table @option 3156 3157@item b 3158Sets target video bitrate. Usually that's around 1:6 of the uncompressed 3159video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher 3160values (close to the uncompressed bitrate) turn on lossless compression mode. 3161 3162@item field_order 3163Enables field coding when set (e.g. to tt - top field first) for interlaced 3164inputs. Should increase compression with interlaced content as it splits the 3165fields and encodes each separately. 3166 3167@item wavelet_depth 3168Sets the total amount of wavelet transforms to apply, between 1 and 5 (default). 3169Lower values reduce compression and quality. Less capable decoders may not be 3170able to handle values of @option{wavelet_depth} over 3. 3171 3172@item wavelet_type 3173Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7} 3174(Deslauriers-Dubuc) 3175are implemented, with 9_7 being the one with better compression and thus 3176is the default. 3177 3178@item slice_width 3179@item slice_height 3180Sets the slice size for each slice. Larger values result in better compression. 3181For compatibility with other more limited decoders use @option{slice_width} of 318232 and @option{slice_height} of 8. 3183 3184@item tolerance 3185Sets the undershoot tolerance of the rate control system in percent. This is 3186to prevent an expensive search from being run. 3187 3188@item qm 3189Sets the quantization matrix preset to use by default or when @option{wavelet_depth} 3190is set to 5 3191@itemize @minus 3192@item 3193@var{default} 3194Uses the default quantization matrix from the specifications, extended with 3195values for the fifth level. This provides a good balance between keeping detail 3196and omitting artifacts. 3197 3198@item 3199@var{flat} 3200Use a completely zeroed out quantization matrix. This increases PSNR but might 3201reduce perception. Use in bogus benchmarks. 3202 3203@item 3204@var{color} 3205Reduces detail but attempts to preserve color at extremely low bitrates. 3206@end itemize 3207 3208@end table 3209 3210@c man end VIDEO ENCODERS 3211 3212@chapter Subtitles Encoders 3213@c man begin SUBTITLES ENCODERS 3214 3215@section dvdsub 3216 3217This codec encodes the bitmap subtitle format that is used in DVDs. 3218Typically they are stored in VOBSUB file pairs (*.idx + *.sub), 3219and they can also be used in Matroska files. 3220 3221@subsection Options 3222 3223@table @option 3224@item palette 3225Specify the global palette used by the bitmaps. 3226 3227The format for this option is a string containing 16 24-bits hexadecimal 3228numbers (without 0x prefix) separated by commas, for example @code{0d00ee, 3229ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1, 32307b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b}. 3231 3232@item even_rows_fix 3233When set to 1, enable a work-around that makes the number of pixel rows 3234even in all subtitles. This fixes a problem with some players that 3235cut off the bottom row if the number is odd. The work-around just adds 3236a fully transparent row if needed. The overhead is low, typically 3237one byte per subtitle on average. 3238 3239By default, this work-around is disabled. 3240@end table 3241 3242@c man end SUBTITLES ENCODERS 3243