1 /* 2 * This file is part of FFmpeg. 3 * 4 * FFmpeg is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU Lesser General Public 6 * License as published by the Free Software Foundation; either 7 * version 2.1 of the License, or (at your option) any later version. 8 * 9 * FFmpeg is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * Lesser General Public License for more details. 13 * 14 * You should have received a copy of the GNU Lesser General Public 15 * License along with FFmpeg; if not, write to the Free Software 16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 17 */ 18 19 #ifndef AVCODEC_CBS_INTERNAL_H 20 #define AVCODEC_CBS_INTERNAL_H 21 22 #include "avcodec.h" 23 #include "cbs.h" 24 #include "get_bits.h" 25 #include "put_bits.h" 26 27 28 enum CBSContentType { 29 // Unit content is a simple structure. 30 CBS_CONTENT_TYPE_POD, 31 // Unit content contains some references to other structures, but all 32 // managed via buffer reference counting. The descriptor defines the 33 // structure offsets of every buffer reference. 34 CBS_CONTENT_TYPE_INTERNAL_REFS, 35 // Unit content is something more complex. The descriptor defines 36 // special functions to manage the content. 37 CBS_CONTENT_TYPE_COMPLEX, 38 }; 39 40 enum { 41 // Maximum number of unit types described by the same unit type 42 // descriptor. 43 CBS_MAX_UNIT_TYPES = 3, 44 // Maximum number of reference buffer offsets in any one unit. 45 CBS_MAX_REF_OFFSETS = 2, 46 // Special value used in a unit type descriptor to indicate that it 47 // applies to a large range of types rather than a set of discrete 48 // values. 49 CBS_UNIT_TYPE_RANGE = -1, 50 }; 51 52 typedef const struct CodedBitstreamUnitTypeDescriptor { 53 // Number of entries in the unit_types array, or the special value 54 // CBS_UNIT_TYPE_RANGE to indicate that the range fields should be 55 // used instead. 56 int nb_unit_types; 57 58 // Array of unit types that this entry describes. 59 const CodedBitstreamUnitType unit_types[CBS_MAX_UNIT_TYPES]; 60 61 // Start and end of unit type range, used if nb_unit_types is 62 // CBS_UNIT_TYPE_RANGE. 63 const CodedBitstreamUnitType unit_type_range_start; 64 const CodedBitstreamUnitType unit_type_range_end; 65 66 // The type of content described. 67 enum CBSContentType content_type; 68 // The size of the structure which should be allocated to contain 69 // the decomposed content of this type of unit. 70 size_t content_size; 71 72 // Number of entries in the ref_offsets array. Only used if the 73 // content_type is CBS_CONTENT_TYPE_INTERNAL_REFS. 74 int nb_ref_offsets; 75 // The structure must contain two adjacent elements: 76 // type *field; 77 // AVBufferRef *field_ref; 78 // where field points to something in the buffer referred to by 79 // field_ref. This offset is then set to offsetof(struct, field). 80 size_t ref_offsets[CBS_MAX_REF_OFFSETS]; 81 82 void (*content_free)(void *opaque, uint8_t *data); 83 int (*content_clone)(AVBufferRef **ref, CodedBitstreamUnit *unit); 84 } CodedBitstreamUnitTypeDescriptor; 85 86 typedef struct CodedBitstreamType { 87 enum AVCodecID codec_id; 88 89 size_t priv_data_size; 90 91 // List of unit type descriptors for this codec. 92 // Terminated by a descriptor with nb_unit_types equal to zero. 93 const CodedBitstreamUnitTypeDescriptor *unit_types; 94 95 // Split frag->data into coded bitstream units, creating the 96 // frag->units array. Fill data but not content on each unit. 97 // The header argument should be set if the fragment came from 98 // a header block, which may require different parsing for some 99 // codecs (e.g. the AVCC header in H.264). 100 int (*split_fragment)(CodedBitstreamContext *ctx, 101 CodedBitstreamFragment *frag, 102 int header); 103 104 // Read the unit->data bitstream and decompose it, creating 105 // unit->content. 106 int (*read_unit)(CodedBitstreamContext *ctx, 107 CodedBitstreamUnit *unit); 108 109 // Write the data bitstream from unit->content into pbc. 110 // Return value AVERROR(ENOSPC) indicates that pbc was too small. 111 int (*write_unit)(CodedBitstreamContext *ctx, 112 CodedBitstreamUnit *unit, 113 PutBitContext *pbc); 114 115 // Read the data from all of frag->units and assemble it into 116 // a bitstream for the whole fragment. 117 int (*assemble_fragment)(CodedBitstreamContext *ctx, 118 CodedBitstreamFragment *frag); 119 120 // Reset the codec internal state. 121 void (*flush)(CodedBitstreamContext *ctx); 122 123 // Free the codec internal state. 124 void (*close)(CodedBitstreamContext *ctx); 125 } CodedBitstreamType; 126 127 128 // Helper functions for trace output. 129 130 void ff_cbs_trace_header(CodedBitstreamContext *ctx, 131 const char *name); 132 133 void ff_cbs_trace_syntax_element(CodedBitstreamContext *ctx, int position, 134 const char *name, const int *subscripts, 135 const char *bitstring, int64_t value); 136 137 138 // Helper functions for read/write of common bitstream elements, including 139 // generation of trace output. 140 141 int ff_cbs_read_unsigned(CodedBitstreamContext *ctx, GetBitContext *gbc, 142 int width, const char *name, 143 const int *subscripts, uint32_t *write_to, 144 uint32_t range_min, uint32_t range_max); 145 146 int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc, 147 int width, const char *name, 148 const int *subscripts, uint32_t value, 149 uint32_t range_min, uint32_t range_max); 150 151 int ff_cbs_read_signed(CodedBitstreamContext *ctx, GetBitContext *gbc, 152 int width, const char *name, 153 const int *subscripts, int32_t *write_to, 154 int32_t range_min, int32_t range_max); 155 156 int ff_cbs_write_signed(CodedBitstreamContext *ctx, PutBitContext *pbc, 157 int width, const char *name, 158 const int *subscripts, int32_t value, 159 int32_t range_min, int32_t range_max); 160 161 // The largest unsigned value representable in N bits, suitable for use as 162 // range_max in the above functions. 163 #define MAX_UINT_BITS(length) ((UINT64_C(1) << (length)) - 1) 164 165 // The largest signed value representable in N bits, suitable for use as 166 // range_max in the above functions. 167 #define MAX_INT_BITS(length) ((INT64_C(1) << ((length) - 1)) - 1) 168 169 // The smallest signed value representable in N bits, suitable for use as 170 // range_min in the above functions. 171 #define MIN_INT_BITS(length) (-(INT64_C(1) << ((length) - 1))) 172 173 174 #define CBS_UNIT_TYPE_POD(type, structure) { \ 175 .nb_unit_types = 1, \ 176 .unit_types = { type }, \ 177 .content_type = CBS_CONTENT_TYPE_POD, \ 178 .content_size = sizeof(structure), \ 179 } 180 #define CBS_UNIT_TYPE_INTERNAL_REF(type, structure, ref_field) { \ 181 .nb_unit_types = 1, \ 182 .unit_types = { type }, \ 183 .content_type = CBS_CONTENT_TYPE_INTERNAL_REFS, \ 184 .content_size = sizeof(structure), \ 185 .nb_ref_offsets = 1, \ 186 .ref_offsets = { offsetof(structure, ref_field) }, \ 187 } 188 #define CBS_UNIT_TYPE_COMPLEX(type, structure, free_func) { \ 189 .nb_unit_types = 1, \ 190 .unit_types = { type }, \ 191 .content_type = CBS_CONTENT_TYPE_COMPLEX, \ 192 .content_size = sizeof(structure), \ 193 .content_free = free_func, \ 194 } 195 #define CBS_UNIT_TYPE_END_OF_LIST { .nb_unit_types = 0 } 196 197 198 extern const CodedBitstreamType ff_cbs_type_av1; 199 extern const CodedBitstreamType ff_cbs_type_h264; 200 extern const CodedBitstreamType ff_cbs_type_h265; 201 extern const CodedBitstreamType ff_cbs_type_jpeg; 202 extern const CodedBitstreamType ff_cbs_type_mpeg2; 203 extern const CodedBitstreamType ff_cbs_type_vp9; 204 205 206 #endif /* AVCODEC_CBS_INTERNAL_H */ 207