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ffmpeg-4.2.2/libavformat/crcenc.c 1.96 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * CRC encoder (for codec/format testing)
   * Copyright (c) 2002 Fabrice Bellard
   *
   * 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 <inttypes.h>
  
  #include "libavutil/adler32.h"
  #include "avformat.h"
  
  typedef struct CRCState {
      uint32_t crcval;
  } CRCState;
  
  static int crc_write_header(struct AVFormatContext *s)
  {
      CRCState *crc = s->priv_data;
  
      /* init CRC */
      crc->crcval = 1;
  
      return 0;
  }
  
  static int crc_write_packet(struct AVFormatContext *s, AVPacket *pkt)
  {
      CRCState *crc = s->priv_data;
      crc->crcval = av_adler32_update(crc->crcval, pkt->data, pkt->size);
      return 0;
  }
  
  static int crc_write_trailer(struct AVFormatContext *s)
  {
      CRCState *crc = s->priv_data;
      char buf[64];
  
      snprintf(buf, sizeof(buf), "CRC=0x%08"PRIx32"\n", crc->crcval);
      avio_write(s->pb, buf, strlen(buf));
  
      return 0;
  }
  
  AVOutputFormat ff_crc_muxer = {
      .name              = "crc",
      .long_name         = NULL_IF_CONFIG_SMALL("CRC testing"),
      .priv_data_size    = sizeof(CRCState),
      .audio_codec       = AV_CODEC_ID_PCM_S16LE,
      .video_codec       = AV_CODEC_ID_RAWVIDEO,
      .write_header      = crc_write_header,
      .write_packet      = crc_write_packet,
      .write_trailer     = crc_write_trailer,
      .flags             = AVFMT_NOTIMESTAMPS,
  };