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rtpdec_mpegts.c
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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;
31 };
32 
34 {
35  return av_mallocz(sizeof(PayloadContext));
36 }
37 
39 {
40  if (!data)
41  return;
42  if (data->ts)
44  av_free(data);
45 }
46 
47 static av_cold int mpegts_init(AVFormatContext *ctx, int st_index,
49 {
50  data->ts = ff_mpegts_parse_open(ctx);
51  if (!data->ts)
52  return AVERROR(ENOMEM);
53  return 0;
54 }
55 
57  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
58  const uint8_t *buf, int len, uint16_t seq,
59  int flags)
60 {
61  int ret;
62 
63  // We don't want to use the RTP timestamps at all. If the mpegts demuxer
64  // doesn't set any pts/dts, the generic rtpdec code shouldn't try to
65  // fill it in either, since the mpegts and RTP timestamps are in totally
66  // different ranges.
67  *timestamp = RTP_NOTS_VALUE;
68 
69  if (!data->ts)
70  return AVERROR(EINVAL);
71 
72  if (!buf) {
73  if (data->read_buf_index >= data->read_buf_size)
74  return AVERROR(EAGAIN);
75  ret = ff_mpegts_parse_packet(data->ts, pkt, data->buf + data->read_buf_index,
76  data->read_buf_size - data->read_buf_index);
77  if (ret < 0)
78  return AVERROR(EAGAIN);
79  data->read_buf_index += ret;
80  if (data->read_buf_index < data->read_buf_size)
81  return 1;
82  else
83  return 0;
84  }
85 
86  ret = ff_mpegts_parse_packet(data->ts, pkt, buf, len);
87  /* The only error that can be returned from ff_mpegts_parse_packet
88  * is "no more data to return from the provided buffer", so return
89  * AVERROR(EAGAIN) for all errors */
90  if (ret < 0)
91  return AVERROR(EAGAIN);
92  if (ret < len) {
93  data->read_buf_size = FFMIN(len - ret, sizeof(data->buf));
94  memcpy(data->buf, buf + ret, data->read_buf_size);
95  data->read_buf_index = 0;
96  return 1;
97  }
98  return 0;
99 }
100 
103  .parse_packet = mpegts_handle_packet,
104  .alloc = mpegts_new_context,
105  .init = mpegts_init,
106  .free = mpegts_free_context,
107  .static_payload_id = 33,
108 };