FFmpeg
rtpdec_ilbc.c
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1 /*
2  * RTP iLBC Depacketizer, RFC 3952
3  * Copyright (c) 2012 Martin Storsjo
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 "avformat.h"
23 #include "rtpdec_formats.h"
24 #include "libavutil/avstring.h"
25 
27  AVStream *stream, PayloadContext *data,
28  const char *attr, const char *value)
29 {
30  if (!strcmp(attr, "mode")) {
31  int mode = atoi(value);
32  switch (mode) {
33  case 20:
34  stream->codecpar->block_align = 38;
35  break;
36  case 30:
37  stream->codecpar->block_align = 50;
38  break;
39  default:
40  av_log(s, AV_LOG_ERROR, "Unsupported iLBC mode %d\n", mode);
41  return AVERROR(EINVAL);
42  }
43  }
44  return 0;
45 }
46 
47 static int ilbc_parse_sdp_line(AVFormatContext *s, int st_index,
48  PayloadContext *data, const char *line)
49 {
50  const char *p;
51  AVStream *st;
52 
53  if (st_index < 0)
54  return 0;
55  st = s->streams[st_index];
56 
57  if (av_strstart(line, "fmtp:", &p)) {
58  int ret = ff_parse_fmtp(s, st, data, p, ilbc_parse_fmtp);
59  if (ret < 0)
60  return ret;
61  if (!st->codecpar->block_align) {
62  av_log(s, AV_LOG_ERROR, "No iLBC mode set\n");
63  return AVERROR(EINVAL);
64  }
65  }
66  return 0;
67 }
68 
70  .enc_name = "iLBC",
71  .codec_type = AVMEDIA_TYPE_AUDIO,
72  .codec_id = AV_CODEC_ID_ILBC,
73  .parse_sdp_a_line = ilbc_parse_sdp_line,
74 };
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
rtpdec_formats.h
ff_parse_fmtp
int ff_parse_fmtp(AVFormatContext *s, AVStream *stream, PayloadContext *data, const char *p, int(*parse_fmtp)(AVFormatContext *s, AVStream *stream, PayloadContext *data, const char *attr, const char *value))
Definition: rtpdec.c:889
data
const char data[16]
Definition: mxf.c:91
RTPDynamicProtocolHandler::enc_name
const char * enc_name
Definition: rtpdec.h:116
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
s
#define s(width, name)
Definition: cbs_vp9.c:257
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVFormatContext
Format I/O context.
Definition: avformat.h:1342
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1017
ilbc_parse_fmtp
static int ilbc_parse_fmtp(AVFormatContext *s, AVStream *stream, PayloadContext *data, const char *attr, const char *value)
Definition: rtpdec_ilbc.c:26
line
Definition: graph2dot.c:48
av_strstart
int av_strstart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str.
Definition: avstring.c:34
AVCodecParameters::block_align
int block_align
Audio only.
Definition: avcodec.h:4074
value
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default value
Definition: writing_filters.txt:86
ff_ilbc_dynamic_handler
const RTPDynamicProtocolHandler ff_ilbc_dynamic_handler
Definition: rtpdec_ilbc.c:69
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:870
avformat.h
mode
mode
Definition: ebur128.h:83
AV_CODEC_ID_ILBC
@ AV_CODEC_ID_ILBC
Definition: avcodec.h:623
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
avstring.h
PayloadContext
RTP/JPEG specific private data.
Definition: rdt.c:83
ilbc_parse_sdp_line
static int ilbc_parse_sdp_line(AVFormatContext *s, int st_index, PayloadContext *data, const char *line)
Definition: rtpdec_ilbc.c:47
RTPDynamicProtocolHandler
Definition: rtpdec.h:115