libavformat/rtpdec_mpegts.c

   1 /*
   2  * RTP MPEG2TS depacketizer
   3  * Copyright (c) 2003 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 "mpegts.h"
  24 #include "rtpdec_formats.h"
  25
  26 struct PayloadContext {
  27     struct MpegTSContext *ts;
  28     int read_buf_index;
  29     int read_buf_size;
  30     uint8_t buf[RTP_MAX_PACKET_LENGTH];
  31 };
  32
  33 static void mpegts_close_context(PayloadContext *data)
  34 {
  35     if (!data)
  36         return;
  37     if (data->ts)
  38         avpriv_mpegts_parse_close(data->ts);
  39 }
  40
  41 static av_cold int mpegts_init(AVFormatContext *ctx, int st_index,
  42                                PayloadContext *data)
  43 {
  44     data->ts = avpriv_mpegts_parse_open(ctx);
  45     if (!data->ts)
  46         return AVERROR(ENOMEM);
  47     return 0;
  48 }
  49
  50 static int mpegts_handle_packet(AVFormatContext *ctx, PayloadContext *data,
  51                                 AVStream *st, AVPacket *pkt, uint32_t *timestamp,
  52                                 const uint8_t *buf, int len, uint16_t seq,
  53                                 int flags)
  54 {
  55     int ret;
  56
  57     // We don't want to use the RTP timestamps at all. If the mpegts demuxer
  58     // doesn't set any pts/dts, the generic rtpdec code shouldn't try to
  59     // fill it in either, since the mpegts and RTP timestamps are in totally
  60     // different ranges.
  61     *timestamp = RTP_NOTS_VALUE;
  62
  63     if (!buf) {
  64         if (data->read_buf_index >= data->read_buf_size)
  65             return AVERROR(EAGAIN);
  66         ret = avpriv_mpegts_parse_packet(data->ts, pkt, data->buf + data->read_buf_index,
  67                                          data->read_buf_size - data->read_buf_index);
  68         if (ret < 0)
  69             return AVERROR(EAGAIN);
  70         data->read_buf_index += ret;
  71         if (data->read_buf_index < data->read_buf_size)
  72             return 1;
  73         else
  74             return 0;
  75     }
  76
  77     ret = avpriv_mpegts_parse_packet(data->ts, pkt, buf, len);
  78     /* The only error that can be returned from avpriv_mpegts_parse_packet
  79      * is "no more data to return from the provided buffer", so return
  80      * AVERROR(EAGAIN) for all errors */
  81     if (ret < 0)
  82         return AVERROR(EAGAIN);
  83     if (ret < len) {
  84         data->read_buf_size = FFMIN(len - ret, sizeof(data->buf));
  85         memcpy(data->buf, buf + ret, data->read_buf_size);
  86         data->read_buf_index = 0;
  87         return 1;
  88     }
  89     return 0;
  90 }
  91
  92 const RTPDynamicProtocolHandler ff_mpegts_dynamic_handler = {
  93     .codec_type        = AVMEDIA_TYPE_DATA,
  94     .priv_data_size    = sizeof(PayloadContext),
  95     .parse_packet      = mpegts_handle_packet,
  96     .init              = mpegts_init,
  97     .close             = mpegts_close_context,
  98     .static_payload_id = 33,
  99 };