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 <stdint.h> 23 24 #include "libavutil/buffer.h" 25 #include "libavutil/log.h" 26 27 #include "cbs.h" 28 #include "codec_id.h" 29 #include "get_bits.h" 30 #include "put_bits.h" 31 32 33 enum CBSContentType { 34 // Unit content is a simple structure. 35 CBS_CONTENT_TYPE_POD, 36 // Unit content contains some references to other structures, but all 37 // managed via buffer reference counting. The descriptor defines the 38 // structure offsets of every buffer reference. 39 CBS_CONTENT_TYPE_INTERNAL_REFS, 40 // Unit content is something more complex. The descriptor defines 41 // special functions to manage the content. 42 CBS_CONTENT_TYPE_COMPLEX, 43 }; 44 45 enum { 46 // Maximum number of unit types described by the same unit type 47 // descriptor. 48 CBS_MAX_UNIT_TYPES = 3, 49 // Maximum number of reference buffer offsets in any one unit. 50 CBS_MAX_REF_OFFSETS = 2, 51 // Special value used in a unit type descriptor to indicate that it 52 // applies to a large range of types rather than a set of discrete 53 // values. 54 CBS_UNIT_TYPE_RANGE = -1, 55 }; 56 57 typedef const struct CodedBitstreamUnitTypeDescriptor { 58 // Number of entries in the unit_types array, or the special value 59 // CBS_UNIT_TYPE_RANGE to indicate that the range fields should be 60 // used instead. 61 int nb_unit_types; 62 63 // Array of unit types that this entry describes. 64 const CodedBitstreamUnitType unit_types[CBS_MAX_UNIT_TYPES]; 65 66 // Start and end of unit type range, used if nb_unit_types is 67 // CBS_UNIT_TYPE_RANGE. 68 const CodedBitstreamUnitType unit_type_range_start; 69 const CodedBitstreamUnitType unit_type_range_end; 70 71 // The type of content described. 72 enum CBSContentType content_type; 73 // The size of the structure which should be allocated to contain 74 // the decomposed content of this type of unit. 75 size_t content_size; 76 77 // Number of entries in the ref_offsets array. Only used if the 78 // content_type is CBS_CONTENT_TYPE_INTERNAL_REFS. 79 int nb_ref_offsets; 80 // The structure must contain two adjacent elements: 81 // type *field; 82 // AVBufferRef *field_ref; 83 // where field points to something in the buffer referred to by 84 // field_ref. This offset is then set to offsetof(struct, field). 85 size_t ref_offsets[CBS_MAX_REF_OFFSETS]; 86 87 void (*content_free)(void *opaque, uint8_t *data); 88 int (*content_clone)(AVBufferRef **ref, CodedBitstreamUnit *unit); 89 } CodedBitstreamUnitTypeDescriptor; 90 91 typedef struct CodedBitstreamType { 92 enum AVCodecID codec_id; 93 94 // A class for the private data, used to declare private AVOptions. 95 // This field is NULL for types that do not declare any options. 96 // If this field is non-NULL, the first member of the filter private data 97 // must be a pointer to AVClass. 98 const AVClass *priv_class; 99 100 size_t priv_data_size; 101 102 // List of unit type descriptors for this codec. 103 // Terminated by a descriptor with nb_unit_types equal to zero. 104 const CodedBitstreamUnitTypeDescriptor *unit_types; 105 106 // Split frag->data into coded bitstream units, creating the 107 // frag->units array. Fill data but not content on each unit. 108 // The header argument should be set if the fragment came from 109 // a header block, which may require different parsing for some 110 // codecs (e.g. the AVCC header in H.264). 111 int (*split_fragment)(CodedBitstreamContext *ctx, 112 CodedBitstreamFragment *frag, 113 int header); 114 115 // Read the unit->data bitstream and decompose it, creating 116 // unit->content. 117 int (*read_unit)(CodedBitstreamContext *ctx, 118 CodedBitstreamUnit *unit); 119 120 // Write the data bitstream from unit->content into pbc. 121 // Return value AVERROR(ENOSPC) indicates that pbc was too small. 122 int (*write_unit)(CodedBitstreamContext *ctx, 123 CodedBitstreamUnit *unit, 124 PutBitContext *pbc); 125 126 // Read the data from all of frag->units and assemble it into 127 // a bitstream for the whole fragment. 128 int (*assemble_fragment)(CodedBitstreamContext *ctx, 129 CodedBitstreamFragment *frag); 130 131 // Reset the codec internal state. 132 void (*flush)(CodedBitstreamContext *ctx); 133 134 // Free the codec internal state. 135 void (*close)(CodedBitstreamContext *ctx); 136 } CodedBitstreamType; 137 138 139 // Helper functions for trace output. 140 141 void ff_cbs_trace_header(CodedBitstreamContext *ctx, 142 const char *name); 143 144 void ff_cbs_trace_syntax_element(CodedBitstreamContext *ctx, int position, 145 const char *name, const int *subscripts, 146 const char *bitstring, int64_t value); 147 148 149 // Helper functions for read/write of common bitstream elements, including 150 // generation of trace output. 151 152 int ff_cbs_read_unsigned(CodedBitstreamContext *ctx, GetBitContext *gbc, 153 int width, const char *name, 154 const int *subscripts, uint32_t *write_to, 155 uint32_t range_min, uint32_t range_max); 156 157 int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc, 158 int width, const char *name, 159 const int *subscripts, uint32_t value, 160 uint32_t range_min, uint32_t range_max); 161 162 int ff_cbs_read_signed(CodedBitstreamContext *ctx, GetBitContext *gbc, 163 int width, const char *name, 164 const int *subscripts, int32_t *write_to, 165 int32_t range_min, int32_t range_max); 166 167 int ff_cbs_write_signed(CodedBitstreamContext *ctx, PutBitContext *pbc, 168 int width, const char *name, 169 const int *subscripts, int32_t value, 170 int32_t range_min, int32_t range_max); 171 172 // The largest unsigned value representable in N bits, suitable for use as 173 // range_max in the above functions. 174 #define MAX_UINT_BITS(length) ((UINT64_C(1) << (length)) - 1) 175 176 // The largest signed value representable in N bits, suitable for use as 177 // range_max in the above functions. 178 #define MAX_INT_BITS(length) ((INT64_C(1) << ((length) - 1)) - 1) 179 180 // The smallest signed value representable in N bits, suitable for use as 181 // range_min in the above functions. 182 #define MIN_INT_BITS(length) (-(INT64_C(1) << ((length) - 1))) 183 184 185 #define CBS_UNIT_TYPE_POD(type, structure) { \ 186 .nb_unit_types = 1, \ 187 .unit_types = { type }, \ 188 .content_type = CBS_CONTENT_TYPE_POD, \ 189 .content_size = sizeof(structure), \ 190 } 191 #define CBS_UNIT_TYPE_INTERNAL_REF(type, structure, ref_field) { \ 192 .nb_unit_types = 1, \ 193 .unit_types = { type }, \ 194 .content_type = CBS_CONTENT_TYPE_INTERNAL_REFS, \ 195 .content_size = sizeof(structure), \ 196 .nb_ref_offsets = 1, \ 197 .ref_offsets = { offsetof(structure, ref_field) }, \ 198 } 199 #define CBS_UNIT_TYPE_COMPLEX(type, structure, free_func) { \ 200 .nb_unit_types = 1, \ 201 .unit_types = { type }, \ 202 .content_type = CBS_CONTENT_TYPE_COMPLEX, \ 203 .content_size = sizeof(structure), \ 204 .content_free = free_func, \ 205 } 206 #define CBS_UNIT_TYPE_END_OF_LIST { .nb_unit_types = 0 } 207 208 209 extern const CodedBitstreamType ff_cbs_type_av1; 210 extern const CodedBitstreamType ff_cbs_type_h264; 211 extern const CodedBitstreamType ff_cbs_type_h265; 212 extern const CodedBitstreamType ff_cbs_type_jpeg; 213 extern const CodedBitstreamType ff_cbs_type_mpeg2; 214 extern const CodedBitstreamType ff_cbs_type_vp9; 215 216 217 #endif /* AVCODEC_CBS_INTERNAL_H */ 218