FFmpeg: libavformat/rtpdec_ilbc.c Source File

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libavformat

rtpdec_ilbc.c

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1 /*

2 * RTP iLBC Depacketizer, RFC 3952

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 */

22 #include "avformat.h"

23 #include "rtpdec_formats.h"

24 #include "libavutil/avstring.h"

26 static int ilbc_parse_fmtp(AVFormatContext *s,

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 }

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;

53 if (st_index < 0)

54 return 0;

55 st = s->streams[st_index];

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 }

69 const RTPDynamicProtocolHandler ff_ilbc_dynamic_handler = {

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:964

data

const char data[16]

Definition: mxf.c:143

RTPDynamicProtocolHandler::enc_name

const char * enc_name

Definition: rtpdec.h:117

AV_LOG_ERROR

#define AV_LOG_ERROR

Something went wrong and cannot losslessly be recovered.

Definition: log.h:180

#define s(width, name)

Definition: cbs_vp9.c:256

AVMEDIA_TYPE_AUDIO

@ AVMEDIA_TYPE_AUDIO

Definition: avutil.h:202

AVFormatContext

Format I/O context.

Definition: avformat.h:1213

AVStream::codecpar

AVCodecParameters * codecpar

Codec parameters associated with this stream.

Definition: avformat.h:1108

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:37

AVCodecParameters::block_align

int block_align

Audio only.

Definition: codec_par.h:184

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

Definition: filter_design.txt:187

AVStream

Stream structure.

Definition: avformat.h:948

avformat.h

mode

Definition: ebur128.h:83