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rtpdec_dv.c
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1 /*
2  * RTP parser for DV payload format (RFC 6469)
3  * Copyright (c) 2015 Thomas Volkert <thomas@homer-conferencing.com>
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/avstring.h"
23 
24 #include "libavcodec/bytestream.h"
25 
26 #include "avio_internal.h"
27 #include "rtpdec_formats.h"
28 
29 struct PayloadContext {
31  uint32_t timestamp;
33 };
34 
36 {
37  ffio_free_dyn_buf(&data->buf);
38 }
39 
41  AVStream *stream,
42  PayloadContext *dv_data,
43  const char *attr, const char *value)
44 {
45  /* does the DV stream include audio? */
46  if (!strcmp(attr, "audio") && !strcmp(value, "bundled"))
47  dv_data->bundled_audio = 1;
48 
49  /* extract the DV profile */
50  if (!strcmp(attr, "encode")) {
51  /* SD-VCR/525-60 */
52  /* SD-VCR/625-50 */
53  /* HD-VCR/1125-60 */
54  /* HD-VCR/1250-50 */
55  /* SDL-VCR/525-60 */
56  /* SDL-VCR/625-50 */
57  /* 314M-25/525-60 */
58  /* 314M-25/625-50 */
59  /* 314M-50/525-60 */
60  /* 314M-50/625-50 */
61  /* 370M/1080-60i */
62  /* 370M/1080-50i */
63  /* 370M/720-60p */
64  /* 370M/720-50p */
65  /* 306M/525-60 (for backward compatibility) */
66  /* 306M/625-50 (for backward compatibility) */
67  }
68 
69  return 0;
70 }
71 
72 static av_cold int dv_parse_sdp_line(AVFormatContext *ctx, int st_index,
73  PayloadContext *dv_data, const char *line)
74 {
75  AVStream *current_stream;
76  const char *sdp_line_ptr = line;
77 
78  if (st_index < 0)
79  return 0;
80 
81  current_stream = ctx->streams[st_index];
82 
83  if (av_strstart(sdp_line_ptr, "fmtp:", &sdp_line_ptr)) {
84  return ff_parse_fmtp(ctx, current_stream, dv_data, sdp_line_ptr,
86  }
87 
88  return 0;
89 }
90 
91 static int dv_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_dv_ctx,
92  AVStream *st, AVPacket *pkt, uint32_t *timestamp,
93  const uint8_t *buf, int len, uint16_t seq,
94  int flags)
95 {
96  int res = 0;
97 
98  /* drop data of previous packets in case of non-continuous (lossy) packet stream */
99  if (rtp_dv_ctx->buf && rtp_dv_ctx->timestamp != *timestamp) {
100  ffio_free_dyn_buf(&rtp_dv_ctx->buf);
101  }
102 
103  /* sanity check for size of input packet: 1 byte payload at least */
104  if (len < 1) {
105  av_log(ctx, AV_LOG_ERROR, "Too short RTP/DV packet, got %d bytes\n", len);
106  return AVERROR_INVALIDDATA;
107  }
108 
109  /* start frame buffering with new dynamic buffer */
110  if (!rtp_dv_ctx->buf) {
111  res = avio_open_dyn_buf(&rtp_dv_ctx->buf);
112  if (res < 0)
113  return res;
114  /* update the timestamp in the frame packet with the one from the RTP packet */
115  rtp_dv_ctx->timestamp = *timestamp;
116  }
117 
118  /* write the fragment to the dyn. buffer */
119  avio_write(rtp_dv_ctx->buf, buf, len);
120 
121  /* RTP marker bit means: last fragment of current frame was received;
122  otherwise, an additional fragment is needed for the current frame */
123  if (!(flags & RTP_FLAG_MARKER))
124  return AVERROR(EAGAIN);
125 
126  /* close frame buffering and create resulting A/V packet */
127  res = ff_rtp_finalize_packet(pkt, &rtp_dv_ctx->buf, st->index);
128  if (res < 0)
129  return res;
130 
131  return 0;
132 }
133 
135  .enc_name = "DV",
136  .codec_type = AVMEDIA_TYPE_VIDEO,
137  .codec_id = AV_CODEC_ID_DVVIDEO,
138  .need_parsing = AVSTREAM_PARSE_FULL,
139  .parse_sdp_a_line = dv_parse_sdp_line,
140  .priv_data_size = sizeof(PayloadContext),
141  .close = dv_close_context,
143 };