libavformat/rtpdec_mpeg12.c

   1 /*
   2  * Common code for the RTP depacketization of MPEG-1/2 formats.
   3  * Copyright (c) 2002 Fabrice Bellard
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/attributes.h"
  23 #include "libavutil/intreadwrite.h"
  24 #include "rtpdec_formats.h"
  25
  26 static int mpeg_parse_packet(AVFormatContext *ctx, PayloadContext *data,
  27                              AVStream *st, AVPacket *pkt, uint32_t *timestamp,
  28                              const uint8_t *buf, int len, uint16_t seq,
  29                              int flags)
  30 {
  31     unsigned int h;
  32     int ret;
  33     if (len <= 4)
  34         return AVERROR_INVALIDDATA;
  35     h    = AV_RB32(buf);
  36     buf += 4;
  37     len -= 4;
  38     if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && h & (1 << 26)) {
  39         /* MPEG-2 */
  40         if (len <= 4)
  41             return AVERROR_INVALIDDATA;
  42         buf += 4;
  43         len -= 4;
  44     }
  45     if ((ret = av_new_packet(pkt, len)) < 0)
  46         return ret;
  47     memcpy(pkt->data, buf, len);
  48     pkt->stream_index = st->index;
  49     return 0;
  50 }
  51
  52 const RTPDynamicProtocolHandler ff_mpeg_audio_dynamic_handler = {
  53     .codec_type        = AVMEDIA_TYPE_AUDIO,
  54     .codec_id          = AV_CODEC_ID_MP3,
  55     .need_parsing      = AVSTREAM_PARSE_FULL,
  56     .parse_packet      = mpeg_parse_packet,
  57     .static_payload_id = 14,
  58 };
  59
  60 const RTPDynamicProtocolHandler ff_mpeg_video_dynamic_handler = {
  61     .codec_type        = AVMEDIA_TYPE_VIDEO,
  62     .codec_id          = AV_CODEC_ID_MPEG2VIDEO,
  63     .need_parsing      = AVSTREAM_PARSE_FULL,
  64     .parse_packet      = mpeg_parse_packet,
  65     .static_payload_id = 32,
  66 };