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ffmpeg-4.2.2/libavformat/iv8.c 3.2 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * Copyright (c) 2009 Michael Niedermayer
   *
   * 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
   */
  
  #include "avformat.h"
  #include "internal.h"
  
  
  static int probe(const AVProbeData *p)
  {
      // the single file I have starts with that, I do not know if others do, too
      if(   p->buf[0] == 1
         && p->buf[1] == 1
         && p->buf[2] == 3
         && p->buf[3] == 0xB8
         && p->buf[4] == 0x80
         && p->buf[5] == 0x60
        )
          return AVPROBE_SCORE_MAX-2;
  
      return 0;
  }
  
  static int read_header(AVFormatContext *s)
  {
      AVStream *st;
  
      st = avformat_new_stream(s, NULL);
      if (!st)
          return AVERROR(ENOMEM);
  
      st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
      st->codecpar->codec_id = AV_CODEC_ID_MPEG4;
      st->need_parsing = AVSTREAM_PARSE_FULL;
      avpriv_set_pts_info(st, 64, 1, 90000);
  
      return 0;
  
  }
  
  static int read_packet(AVFormatContext *s, AVPacket *pkt)
  {
      int ret, size, pts, type, flags;
      int first_pkt      = 0;
      int frame_complete = 0;
  
      while (!frame_complete) {
  
          type  = avio_rb16(s->pb); // 257 or 258
          size  = avio_rb16(s->pb);
          flags = avio_rb16(s->pb); //some flags, 0x80 indicates end of frame
                  avio_rb16(s->pb); //packet number
          pts   = avio_rb32(s->pb);
                  avio_rb32(s->pb); //6A 13 E3 88
  
          frame_complete = flags & 0x80;
  
          size -= 12;
          if (size < 1)
              return -1;
  
          if (type == 258) {
              avio_skip(s->pb, size);
              frame_complete = 0;
              continue;
          }
  
          if (!first_pkt) {
              ret = av_get_packet(s->pb, pkt, size);
              if (ret < 0)
                  return ret;
              first_pkt = 1;
              pkt->pts  = pts;
              pkt->pos -= 16;
          } else {
              ret = av_append_packet(s->pb, pkt, size);
              if (ret < 0) {
                  av_log(s, AV_LOG_ERROR, "failed to grow packet\n");
                  av_packet_unref(pkt);
                  return ret;
              }
          }
          if (ret < size) {
              av_log(s, AV_LOG_ERROR, "Truncated packet! Read %d of %d bytes\n",
                     ret, size);
              pkt->flags |= AV_PKT_FLAG_CORRUPT;
              break;
          }
      }
      pkt->stream_index = 0;
  
      return 0;
  }
  
  AVInputFormat ff_iv8_demuxer = {
      .name           = "iv8",
      .long_name      = NULL_IF_CONFIG_SMALL("IndigoVision 8000 video"),
      .read_probe     = probe,
      .read_header    = read_header,
      .read_packet    = read_packet,
      .flags          = AVFMT_GENERIC_INDEX,
  };