1 /* 2 * pixel format descriptor 3 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at> 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22 #ifndef AVUTIL_PIXDESC_H 23 #define AVUTIL_PIXDESC_H 24 25 #include <inttypes.h> 26 27 #include "attributes.h" 28 #include "pixfmt.h" 29 #include "version.h" 30 31 typedef struct AVComponentDescriptor { 32 /** 33 * Which of the 4 planes contains the component. 34 */ 35 int plane; 36 37 /** 38 * Number of elements between 2 horizontally consecutive pixels. 39 * Elements are bits for bitstream formats, bytes otherwise. 40 */ 41 int step; 42 43 /** 44 * Number of elements before the component of the first pixel. 45 * Elements are bits for bitstream formats, bytes otherwise. 46 */ 47 int offset; 48 49 /** 50 * Number of least significant bits that must be shifted away 51 * to get the value. 52 */ 53 int shift; 54 55 /** 56 * Number of bits in the component. 57 */ 58 int depth; 59 60 #if FF_API_PLUS1_MINUS1 61 /** deprecated, use step instead */ 62 attribute_deprecated int step_minus1; 63 64 /** deprecated, use depth instead */ 65 attribute_deprecated int depth_minus1; 66 67 /** deprecated, use offset instead */ 68 attribute_deprecated int offset_plus1; 69 #endif 70 } AVComponentDescriptor; 71 72 /** 73 * Descriptor that unambiguously describes how the bits of a pixel are 74 * stored in the up to 4 data planes of an image. It also stores the 75 * subsampling factors and number of components. 76 * 77 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV 78 * and all the YUV variants) AVPixFmtDescriptor just stores how values 79 * are stored not what these values represent. 80 */ 81 typedef struct AVPixFmtDescriptor { 82 const char *name; 83 uint8_t nb_components; ///< The number of components each pixel has, (1-4) 84 85 /** 86 * Amount to shift the luma width right to find the chroma width. 87 * For YV12 this is 1 for example. 88 * chroma_width = AV_CEIL_RSHIFT(luma_width, log2_chroma_w) 89 * The note above is needed to ensure rounding up. 90 * This value only refers to the chroma components. 91 */ 92 uint8_t log2_chroma_w; 93 94 /** 95 * Amount to shift the luma height right to find the chroma height. 96 * For YV12 this is 1 for example. 97 * chroma_height= AV_CEIL_RSHIFT(luma_height, log2_chroma_h) 98 * The note above is needed to ensure rounding up. 99 * This value only refers to the chroma components. 100 */ 101 uint8_t log2_chroma_h; 102 103 /** 104 * Combination of AV_PIX_FMT_FLAG_... flags. 105 */ 106 uint64_t flags; 107 108 /** 109 * Parameters that describe how pixels are packed. 110 * If the format has 1 or 2 components, then luma is 0. 111 * If the format has 3 or 4 components: 112 * if the RGB flag is set then 0 is red, 1 is green and 2 is blue; 113 * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V. 114 * 115 * If present, the Alpha channel is always the last component. 116 */ 117 AVComponentDescriptor comp[4]; 118 119 /** 120 * Alternative comma-separated names. 121 */ 122 const char *alias; 123 } AVPixFmtDescriptor; 124 125 /** 126 * Pixel format is big-endian. 127 */ 128 #define AV_PIX_FMT_FLAG_BE (1 << 0) 129 /** 130 * Pixel format has a palette in data[1], values are indexes in this palette. 131 */ 132 #define AV_PIX_FMT_FLAG_PAL (1 << 1) 133 /** 134 * All values of a component are bit-wise packed end to end. 135 */ 136 #define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2) 137 /** 138 * Pixel format is an HW accelerated format. 139 */ 140 #define AV_PIX_FMT_FLAG_HWACCEL (1 << 3) 141 /** 142 * At least one pixel component is not in the first data plane. 143 */ 144 #define AV_PIX_FMT_FLAG_PLANAR (1 << 4) 145 /** 146 * The pixel format contains RGB-like data (as opposed to YUV/grayscale). 147 */ 148 #define AV_PIX_FMT_FLAG_RGB (1 << 5) 149 150 /** 151 * The pixel format is "pseudo-paletted". This means that it contains a 152 * fixed palette in the 2nd plane but the palette is fixed/constant for each 153 * PIX_FMT. This allows interpreting the data as if it was PAL8, which can 154 * in some cases be simpler. Or the data can be interpreted purely based on 155 * the pixel format without using the palette. 156 * An example of a pseudo-paletted format is AV_PIX_FMT_GRAY8 157 * 158 * @deprecated This flag is deprecated, and will be removed. When it is removed, 159 * the extra palette allocation in AVFrame.data[1] is removed as well. Only 160 * actual paletted formats (as indicated by AV_PIX_FMT_FLAG_PAL) will have a 161 * palette. Starting with FFmpeg versions which have this flag deprecated, the 162 * extra "pseudo" palette is already ignored, and API users are not required to 163 * allocate a palette for AV_PIX_FMT_FLAG_PSEUDOPAL formats (it was required 164 * before the deprecation, though). 165 */ 166 #define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6) 167 168 /** 169 * The pixel format has an alpha channel. This is set on all formats that 170 * support alpha in some way, including AV_PIX_FMT_PAL8. The alpha is always 171 * straight, never pre-multiplied. 172 * 173 * If a codec or a filter does not support alpha, it should set all alpha to 174 * opaque, or use the equivalent pixel formats without alpha component, e.g. 175 * AV_PIX_FMT_RGB0 (or AV_PIX_FMT_RGB24 etc.) instead of AV_PIX_FMT_RGBA. 176 */ 177 #define AV_PIX_FMT_FLAG_ALPHA (1 << 7) 178 179 /** 180 * The pixel format is following a Bayer pattern 181 */ 182 #define AV_PIX_FMT_FLAG_BAYER (1 << 8) 183 184 /** 185 * The pixel format contains IEEE-754 floating point values. Precision (double, 186 * single, or half) should be determined by the pixel size (64, 32, or 16 bits). 187 */ 188 #define AV_PIX_FMT_FLAG_FLOAT (1 << 9) 189 190 /** 191 * Return the number of bits per pixel used by the pixel format 192 * described by pixdesc. Note that this is not the same as the number 193 * of bits per sample. 194 * 195 * The returned number of bits refers to the number of bits actually 196 * used for storing the pixel information, that is padding bits are 197 * not counted. 198 */ 199 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc); 200 201 /** 202 * Return the number of bits per pixel for the pixel format 203 * described by pixdesc, including any padding or unused bits. 204 */ 205 int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc); 206 207 /** 208 * @return a pixel format descriptor for provided pixel format or NULL if 209 * this pixel format is unknown. 210 */ 211 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt); 212 213 /** 214 * Iterate over all pixel format descriptors known to libavutil. 215 * 216 * @param prev previous descriptor. NULL to get the first descriptor. 217 * 218 * @return next descriptor or NULL after the last descriptor 219 */ 220 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev); 221 222 /** 223 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc 224 * is not a valid pointer to a pixel format descriptor. 225 */ 226 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc); 227 228 /** 229 * Utility function to access log2_chroma_w log2_chroma_h from 230 * the pixel format AVPixFmtDescriptor. 231 * 232 * @param[in] pix_fmt the pixel format 233 * @param[out] h_shift store log2_chroma_w (horizontal/width shift) 234 * @param[out] v_shift store log2_chroma_h (vertical/height shift) 235 * 236 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format 237 */ 238 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt, 239 int *h_shift, int *v_shift); 240 241 /** 242 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a 243 * valid pixel format. 244 */ 245 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt); 246 247 /** 248 * @return the name for provided color range or NULL if unknown. 249 */ 250 const char *av_color_range_name(enum AVColorRange range); 251 252 /** 253 * @return the AVColorRange value for name or an AVError if not found. 254 */ 255 int av_color_range_from_name(const char *name); 256 257 /** 258 * @return the name for provided color primaries or NULL if unknown. 259 */ 260 const char *av_color_primaries_name(enum AVColorPrimaries primaries); 261 262 /** 263 * @return the AVColorPrimaries value for name or an AVError if not found. 264 */ 265 int av_color_primaries_from_name(const char *name); 266 267 /** 268 * @return the name for provided color transfer or NULL if unknown. 269 */ 270 const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer); 271 272 /** 273 * @return the AVColorTransferCharacteristic value for name or an AVError if not found. 274 */ 275 int av_color_transfer_from_name(const char *name); 276 277 /** 278 * @return the name for provided color space or NULL if unknown. 279 */ 280 const char *av_color_space_name(enum AVColorSpace space); 281 282 /** 283 * @return the AVColorSpace value for name or an AVError if not found. 284 */ 285 int av_color_space_from_name(const char *name); 286 287 /** 288 * @return the name for provided chroma location or NULL if unknown. 289 */ 290 const char *av_chroma_location_name(enum AVChromaLocation location); 291 292 /** 293 * @return the AVChromaLocation value for name or an AVError if not found. 294 */ 295 int av_chroma_location_from_name(const char *name); 296 297 /** 298 * Return the pixel format corresponding to name. 299 * 300 * If there is no pixel format with name name, then looks for a 301 * pixel format with the name corresponding to the native endian 302 * format of name. 303 * For example in a little-endian system, first looks for "gray16", 304 * then for "gray16le". 305 * 306 * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE. 307 */ 308 enum AVPixelFormat av_get_pix_fmt(const char *name); 309 310 /** 311 * Return the short name for a pixel format, NULL in case pix_fmt is 312 * unknown. 313 * 314 * @see av_get_pix_fmt(), av_get_pix_fmt_string() 315 */ 316 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt); 317 318 /** 319 * Print in buf the string corresponding to the pixel format with 320 * number pix_fmt, or a header if pix_fmt is negative. 321 * 322 * @param buf the buffer where to write the string 323 * @param buf_size the size of buf 324 * @param pix_fmt the number of the pixel format to print the 325 * corresponding info string, or a negative value to print the 326 * corresponding header. 327 */ 328 char *av_get_pix_fmt_string(char *buf, int buf_size, 329 enum AVPixelFormat pix_fmt); 330 331 /** 332 * Read a line from an image, and write the values of the 333 * pixel format component c to dst. 334 * 335 * @param data the array containing the pointers to the planes of the image 336 * @param linesize the array containing the linesizes of the image 337 * @param desc the pixel format descriptor for the image 338 * @param x the horizontal coordinate of the first pixel to read 339 * @param y the vertical coordinate of the first pixel to read 340 * @param w the width of the line to read, that is the number of 341 * values to write to dst 342 * @param read_pal_component if not zero and the format is a paletted 343 * format writes the values corresponding to the palette 344 * component c in data[1] to dst, rather than the palette indexes in 345 * data[0]. The behavior is undefined if the format is not paletted. 346 * @param dst_element_size size of elements in dst array (2 or 4 byte) 347 */ 348 void av_read_image_line2(void *dst, const uint8_t *data[4], 349 const int linesize[4], const AVPixFmtDescriptor *desc, 350 int x, int y, int c, int w, int read_pal_component, 351 int dst_element_size); 352 353 void av_read_image_line(uint16_t *dst, const uint8_t *data[4], 354 const int linesize[4], const AVPixFmtDescriptor *desc, 355 int x, int y, int c, int w, int read_pal_component); 356 357 /** 358 * Write the values from src to the pixel format component c of an 359 * image line. 360 * 361 * @param src array containing the values to write 362 * @param data the array containing the pointers to the planes of the 363 * image to write into. It is supposed to be zeroed. 364 * @param linesize the array containing the linesizes of the image 365 * @param desc the pixel format descriptor for the image 366 * @param x the horizontal coordinate of the first pixel to write 367 * @param y the vertical coordinate of the first pixel to write 368 * @param w the width of the line to write, that is the number of 369 * values to write to the image line 370 * @param src_element_size size of elements in src array (2 or 4 byte) 371 */ 372 void av_write_image_line2(const void *src, uint8_t *data[4], 373 const int linesize[4], const AVPixFmtDescriptor *desc, 374 int x, int y, int c, int w, int src_element_size); 375 376 void av_write_image_line(const uint16_t *src, uint8_t *data[4], 377 const int linesize[4], const AVPixFmtDescriptor *desc, 378 int x, int y, int c, int w); 379 380 /** 381 * Utility function to swap the endianness of a pixel format. 382 * 383 * @param[in] pix_fmt the pixel format 384 * 385 * @return pixel format with swapped endianness if it exists, 386 * otherwise AV_PIX_FMT_NONE 387 */ 388 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt); 389 390 #define FF_LOSS_RESOLUTION 0x0001 /**< loss due to resolution change */ 391 #define FF_LOSS_DEPTH 0x0002 /**< loss due to color depth change */ 392 #define FF_LOSS_COLORSPACE 0x0004 /**< loss due to color space conversion */ 393 #define FF_LOSS_ALPHA 0x0008 /**< loss of alpha bits */ 394 #define FF_LOSS_COLORQUANT 0x0010 /**< loss due to color quantization */ 395 #define FF_LOSS_CHROMA 0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */ 396 397 /** 398 * Compute what kind of losses will occur when converting from one specific 399 * pixel format to another. 400 * When converting from one pixel format to another, information loss may occur. 401 * For example, when converting from RGB24 to GRAY, the color information will 402 * be lost. Similarly, other losses occur when converting from some formats to 403 * other formats. These losses can involve loss of chroma, but also loss of 404 * resolution, loss of color depth, loss due to the color space conversion, loss 405 * of the alpha bits or loss due to color quantization. 406 * av_get_fix_fmt_loss() informs you about the various types of losses 407 * which will occur when converting from one pixel format to another. 408 * 409 * @param[in] dst_pix_fmt destination pixel format 410 * @param[in] src_pix_fmt source pixel format 411 * @param[in] has_alpha Whether the source pixel format alpha channel is used. 412 * @return Combination of flags informing you what kind of losses will occur 413 * (maximum loss for an invalid dst_pix_fmt). 414 */ 415 int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt, 416 enum AVPixelFormat src_pix_fmt, 417 int has_alpha); 418 419 /** 420 * Compute what kind of losses will occur when converting from one specific 421 * pixel format to another. 422 * When converting from one pixel format to another, information loss may occur. 423 * For example, when converting from RGB24 to GRAY, the color information will 424 * be lost. Similarly, other losses occur when converting from some formats to 425 * other formats. These losses can involve loss of chroma, but also loss of 426 * resolution, loss of color depth, loss due to the color space conversion, loss 427 * of the alpha bits or loss due to color quantization. 428 * av_get_fix_fmt_loss() informs you about the various types of losses 429 * which will occur when converting from one pixel format to another. 430 * 431 * @param[in] dst_pix_fmt destination pixel format 432 * @param[in] src_pix_fmt source pixel format 433 * @param[in] has_alpha Whether the source pixel format alpha channel is used. 434 * @return Combination of flags informing you what kind of losses will occur 435 * (maximum loss for an invalid dst_pix_fmt). 436 */ 437 enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2, 438 enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr); 439 440 #endif /* AVUTIL_PIXDESC_H */ 441