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ffmpeg-4.2.2/libavcodec/cbs_internal.h 4.51 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #ifndef AVCODEC_CBS_INTERNAL_H
  #define AVCODEC_CBS_INTERNAL_H
  
  #include "avcodec.h"
  #include "cbs.h"
  #include "get_bits.h"
  #include "put_bits.h"
  
  
  typedef struct CodedBitstreamType {
      enum AVCodecID codec_id;
  
      size_t priv_data_size;
  
      // Split frag->data into coded bitstream units, creating the
      // frag->units array.  Fill data but not content on each unit.
      // The header argument should be set if the fragment came from
      // a header block, which may require different parsing for some
      // codecs (e.g. the AVCC header in H.264).
      int (*split_fragment)(CodedBitstreamContext *ctx,
                            CodedBitstreamFragment *frag,
                            int header);
  
      // Read the unit->data bitstream and decompose it, creating
      // unit->content.
      int (*read_unit)(CodedBitstreamContext *ctx,
                       CodedBitstreamUnit *unit);
  
      // Write the data bitstream from unit->content into pbc.
      // Return value AVERROR(ENOSPC) indicates that pbc was too small.
      int (*write_unit)(CodedBitstreamContext *ctx,
                        CodedBitstreamUnit *unit,
                        PutBitContext *pbc);
  
      // Read the data from all of frag->units and assemble it into
      // a bitstream for the whole fragment.
      int (*assemble_fragment)(CodedBitstreamContext *ctx,
                               CodedBitstreamFragment *frag);
  
      // Free the codec internal state.
      void (*close)(CodedBitstreamContext *ctx);
  } CodedBitstreamType;
  
  
  // Helper functions for trace output.
  
  void ff_cbs_trace_header(CodedBitstreamContext *ctx,
                           const char *name);
  
  void ff_cbs_trace_syntax_element(CodedBitstreamContext *ctx, int position,
                                   const char *name, const int *subscripts,
                                   const char *bitstring, int64_t value);
  
  
  // Helper functions for read/write of common bitstream elements, including
  // generation of trace output.
  
  int ff_cbs_read_unsigned(CodedBitstreamContext *ctx, GetBitContext *gbc,
                           int width, const char *name,
                           const int *subscripts, uint32_t *write_to,
                           uint32_t range_min, uint32_t range_max);
  
  int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc,
                            int width, const char *name,
                            const int *subscripts, uint32_t value,
                            uint32_t range_min, uint32_t range_max);
  
  int ff_cbs_read_signed(CodedBitstreamContext *ctx, GetBitContext *gbc,
                         int width, const char *name,
                         const int *subscripts, int32_t *write_to,
                         int32_t range_min, int32_t range_max);
  
  int ff_cbs_write_signed(CodedBitstreamContext *ctx, PutBitContext *pbc,
                          int width, const char *name,
                          const int *subscripts, int32_t value,
                          int32_t range_min, int32_t range_max);
  
  // The largest unsigned value representable in N bits, suitable for use as
  // range_max in the above functions.
  #define MAX_UINT_BITS(length) ((UINT64_C(1) << (length)) - 1)
  
  // The largest signed value representable in N bits, suitable for use as
  // range_max in the above functions.
  #define MAX_INT_BITS(length) ((INT64_C(1) << ((length) - 1)) - 1)
  
  // The smallest signed value representable in N bits, suitable for use as
  // range_min in the above functions.
  #define MIN_INT_BITS(length) (-(INT64_C(1) << ((length) - 1)))
  
  
  extern const CodedBitstreamType ff_cbs_type_av1;
  extern const CodedBitstreamType ff_cbs_type_h264;
  extern const CodedBitstreamType ff_cbs_type_h265;
  extern const CodedBitstreamType ff_cbs_type_jpeg;
  extern const CodedBitstreamType ff_cbs_type_mpeg2;
  extern const CodedBitstreamType ff_cbs_type_vp9;
  
  
  #endif /* AVCODEC_CBS_INTERNAL_H */