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ffmpeg-4.2.2/libavcodec/rv34_parser.c 2.55 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * RV30/40 parser
   * Copyright (c) 2011 Konstantin Shishkov
   *
   * 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
   */
  
  /**
   * @file
   * RV30/40 parser
   */
  
  #include "parser.h"
  #include "libavutil/intreadwrite.h"
  
  typedef struct RV34ParseContext {
      ParseContext pc;
      int64_t key_dts;
      int key_pts;
  } RV34ParseContext;
  
  static const int rv_to_av_frame_type[4] = {
      AV_PICTURE_TYPE_I, AV_PICTURE_TYPE_I, AV_PICTURE_TYPE_P, AV_PICTURE_TYPE_B,
  };
  
  static int rv34_parse(AVCodecParserContext *s,
                        AVCodecContext *avctx,
                        const uint8_t **poutbuf, int *poutbuf_size,
                        const uint8_t *buf, int buf_size)
  {
      RV34ParseContext *pc = s->priv_data;
      int type, pts, hdr;
  
      if (buf_size < 13 + *buf * 8) {
          *poutbuf = buf;
          *poutbuf_size = buf_size;
          return buf_size;
      }
  
      hdr = AV_RB32(buf + 9 + *buf * 8);
      if (avctx->codec_id == AV_CODEC_ID_RV30) {
          type = (hdr >> 27) & 3;
          pts  = (hdr >>  7) & 0x1FFF;
      } else {
          type = (hdr >> 29) & 3;
          pts  = (hdr >>  6) & 0x1FFF;
      }
  
      if (type != 3 && s->pts != AV_NOPTS_VALUE) {
          pc->key_dts = s->pts;
          pc->key_pts = pts;
      } else {
          if (type != 3)
              s->pts = pc->key_dts + ((pts - pc->key_pts) & 0x1FFF);
          else
              s->pts = pc->key_dts - ((pc->key_pts - pts) & 0x1FFF);
      }
      s->pict_type = rv_to_av_frame_type[type];
  
      *poutbuf = buf;
      *poutbuf_size = buf_size;
      return buf_size;
  }
  
  #if CONFIG_RV30_PARSER
  AVCodecParser ff_rv30_parser = {
      .codec_ids      = { AV_CODEC_ID_RV30 },
      .priv_data_size = sizeof(RV34ParseContext),
      .parser_parse   = rv34_parse,
  };
  #endif
  
  #if CONFIG_RV40_PARSER
  AVCodecParser ff_rv40_parser = {
      .codec_ids      = { AV_CODEC_ID_RV40 },
      .priv_data_size = sizeof(RV34ParseContext),
      .parser_parse   = rv34_parse,
  };
  #endif