FFmpeg: libavformat/sdxdec.c Source File

FFmpeg

libavformat

sdxdec.c

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1 /*

2 * SDX demuxer

3 * Copyright (c) 2017 Paul B Mahol

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 #include "libavutil/intreadwrite.h"

24 #include "avformat.h"

25 #include "internal.h"

26 #include "pcm.h"

27

28 static int sdx_probe(const AVProbeData *p)

29 {

30 if (AV_RB32(p->buf) == AV_RB32("SDX:"))

31 return AVPROBE_SCORE_EXTENSION;

32 return 0;

33 }

34

35 static int sdx_read_header(AVFormatContext *s)

36 {

37 AVStream *st;

38 int depth, length;

39

40 avio_skip(s->pb, 4);

41 while (!avio_feof(s->pb)) {

42 if (avio_r8(s->pb) == 0x1a)

43 break;

44 }

45 if (avio_r8(s->pb) != 1)

46 return AVERROR_INVALIDDATA;

47 length = avio_r8(s->pb);

48 avio_skip(s->pb, length);

49 avio_skip(s->pb, 4);

50 depth = avio_r8(s->pb);

51

52 st = avformat_new_stream(s, NULL);

53 if (!st)

54 return AVERROR(ENOMEM);

55

56 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;

57 st->codecpar->ch_layout.nb_channels = 1;

58 st->codecpar->sample_rate = avio_rl32(s->pb);

59 switch (depth) {

60 case 8:

61 st->codecpar->codec_id = AV_CODEC_ID_PCM_U8;

62 break;

63 case 16:

64 st->codecpar->codec_id = AV_CODEC_ID_PCM_U16LE;

65 break;

66 case 24:

67 st->codecpar->codec_id = AV_CODEC_ID_PCM_U24LE;

68 break;

69 case 32:

70 st->codecpar->codec_id = AV_CODEC_ID_PCM_U32LE;

71 break;

72 default:

73 return AVERROR_INVALIDDATA;

74 }

75 avio_skip(s->pb, 16);

76 st->codecpar->block_align = depth / 8;

77

78 return 0;

79 }

80

81 const AVInputFormat ff_sdx_demuxer = {

82 .name = "sdx",

83 .long_name = NULL_IF_CONFIG_SMALL("Sample Dump eXchange"),

84 .read_probe = sdx_probe,

85 .read_header = sdx_read_header,

86 .read_packet = ff_pcm_read_packet,

87 .read_seek = ff_pcm_read_seek,

88 .extensions = "sdx",

89 .flags = AVFMT_GENERIC_INDEX,

90 };

sdx_read_header

static int sdx_read_header(AVFormatContext *s)

Definition: sdxdec.c:35

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

avformat_new_stream

AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)

Add a new stream to a media file.

Definition: options.c:237

AVCodecParameters::codec_type

enum AVMediaType codec_type

General type of the encoded data.

Definition: codec_par.h:57

const AVInputFormat ff_sdx_demuxer

Definition: sdxdec.c:81

AV_CODEC_ID_PCM_U24LE

@ AV_CODEC_ID_PCM_U24LE

Definition: codec_id.h:332

AVChannelLayout::nb_channels

int nb_channels

Number of channels in this layout.

Definition: channel_layout.h:300

AVFMT_GENERIC_INDEX

#define AVFMT_GENERIC_INDEX

Use generic index building code.

Definition: avformat.h:482

Definition: avformat.h:656

s

#define s(width, name)

Definition: cbs_vp9.c:256

AVInputFormat::name

const char * name

A comma separated list of short names for the format.

Definition: avformat.h:661

AVProbeData::buf

unsigned char * buf

Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.

Definition: avformat.h:455

AVMEDIA_TYPE_AUDIO

@ AVMEDIA_TYPE_AUDIO

Definition: avutil.h:202

static int sdx_probe(const AVProbeData *p)

Definition: sdxdec.c:28

AVFormatContext

Format I/O context.

Definition: avformat.h:1213

AVStream::codecpar

AVCodecParameters * codecpar

Codec parameters associated with this stream.

Definition: avformat.h:1108

#define NULL

Definition: coverity.c:32

This structure contains the data a format has to probe a file.

Definition: avformat.h:453

AVCodecParameters::ch_layout

AVChannelLayout ch_layout

Audio only.

Definition: codec_par.h:212

AVPROBE_SCORE_EXTENSION

#define AVPROBE_SCORE_EXTENSION

score for file extension

Definition: avformat.h:463

AVCodecParameters::sample_rate

int sample_rate

Audio only.

Definition: codec_par.h:177

unsigned int avio_rl32(AVIOContext *s)

Definition: aviobuf.c:759

NULL_IF_CONFIG_SMALL

#define NULL_IF_CONFIG_SMALL(x)

Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.

Definition: internal.h:117

uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_RB32

Definition: bytestream.h:96

int avio_r8(AVIOContext *s)

Definition: aviobuf.c:632

AVCodecParameters::block_align

int block_align

Audio only.

Definition: codec_par.h:184

ff_pcm_read_packet

int ff_pcm_read_packet(AVFormatContext *s, AVPacket *pkt)

Definition: pcm.c:29

Stream structure.

Definition: avformat.h:948

ff_pcm_read_seek

int ff_pcm_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)

Definition: pcm.c:56

AV_CODEC_ID_PCM_U32LE

@ AV_CODEC_ID_PCM_U32LE

Definition: codec_id.h:328

int64_t avio_skip(AVIOContext *s, int64_t offset)

Skip given number of bytes forward.

Definition: aviobuf.c:347

AV_CODEC_ID_PCM_U8

@ AV_CODEC_ID_PCM_U8

Definition: codec_id.h:323

AVCodecParameters::codec_id

enum AVCodecID codec_id

Specific type of the encoded data (the codec used).

Definition: codec_par.h:61

AV_CODEC_ID_PCM_U16LE

@ AV_CODEC_ID_PCM_U16LE

Definition: codec_id.h:320

AVERROR_INVALIDDATA

#define AVERROR_INVALIDDATA

Invalid data found when processing input.

Definition: error.h:61

int avio_feof(AVIOContext *s)

Similar to feof() but also returns nonzero on read errors.

Definition: aviobuf.c:375

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