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gsmdec.c
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1 /*
2  * RAW GSM demuxer
3  * Copyright (c) 2011 Justin Ruggles
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 
23 #include "libavutil/mathematics.h"
24 #include "libavutil/opt.h"
25 #include "avformat.h"
26 #include "internal.h"
27 
28 #define GSM_BLOCK_SIZE 33
29 #define GSM_BLOCK_SAMPLES 160
30 #define GSM_SAMPLE_RATE 8000
31 
32 typedef struct GSMDemuxerContext {
33  AVClass *class;
36 
38 {
39  int ret, size;
40 
41  size = GSM_BLOCK_SIZE;
42 
43  pkt->pos = avio_tell(s->pb);
44  pkt->stream_index = 0;
45 
46  ret = av_get_packet(s->pb, pkt, size);
47  if (ret < GSM_BLOCK_SIZE) {
48  av_free_packet(pkt);
49  return ret < 0 ? ret : AVERROR(EIO);
50  }
51  pkt->duration = 1;
52  pkt->pts = pkt->pos / GSM_BLOCK_SIZE;
53 
54  return 0;
55 }
56 
58 {
61  if (!st)
62  return AVERROR(ENOMEM);
63 
66  st->codec->channels = 1;
68  st->codec->sample_rate = c->sample_rate;
70 
72 
73  return 0;
74 }
75 
76 static const AVOption options[] = {
77  { "sample_rate", "", offsetof(GSMDemuxerContext, sample_rate),
78  AV_OPT_TYPE_INT, {.i64 = GSM_SAMPLE_RATE}, 1, INT_MAX / GSM_BLOCK_SIZE,
80  { NULL },
81 };
82 
83 static const AVClass gsm_class = {
84  .class_name = "gsm demuxer",
85  .item_name = av_default_item_name,
86  .option = options,
87  .version = LIBAVUTIL_VERSION_INT,
88 };
89 
91  .name = "gsm",
92  .long_name = NULL_IF_CONFIG_SMALL("raw GSM"),
93  .priv_data_size = sizeof(GSMDemuxerContext),
97  .extensions = "gsm",
98  .raw_codec_id = AV_CODEC_ID_GSM,
99  .priv_class = &gsm_class,
100 };
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:631
void av_free_packet(AVPacket *pkt)
Free a packet.
Definition: avpacket.c:280
AVOption.
Definition: opt.h:255
#define LIBAVUTIL_VERSION_INT
Definition: version.h:62
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1447
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4071
static const AVOption options[]
Definition: gsmdec.c:76
static AVPacket pkt
Format I/O context.
Definition: avformat.h:1272
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
AVOptions.
#define GSM_BLOCK_SIZE
Definition: gsmdec.c:28
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:3737
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:241
ptrdiff_t size
Definition: opengl_enc.c:101
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:390
int duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:1440
av_default_item_name
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:175
static const AVClass gsm_class
Definition: gsmdec.c:83
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:2322
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:861
int bit_rate
the average bitrate
Definition: avcodec.h:1566
audio channel layout utility functions
ret
Definition: avfilter.c:974
#define GSM_SAMPLE_RATE
Definition: gsmdec.c:30
static int gsm_read_header(AVFormatContext *s)
Definition: gsmdec.c:57
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:620
Stream structure.
Definition: avformat.h:842
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
sample_rate
enum AVMediaType codec_type
Definition: avcodec.h:1509
enum AVCodecID codec_id
Definition: avcodec.h:1518
int sample_rate
samples per second
Definition: avcodec.h:2261
AVIOContext * pb
I/O context.
Definition: avformat.h:1314
#define GSM_BLOCK_SAMPLES
Definition: gsmdec.c:29
Describe the class of an AVClass context structure.
Definition: log.h:67
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:473
#define AV_OPT_FLAG_DECODING_PARAM
a generic parameter which can be set by the user for demuxing or decoding
Definition: opt.h:286
AVInputFormat ff_gsm_demuxer
Definition: gsmdec.c:90
static int gsm_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: gsmdec.c:37
int raw_codec_id
Raw demuxers store their codec ID here.
Definition: avformat.h:674
static int flags
Definition: cpu.c:47
Main libavformat public API header.
static double c[64]
struct AVInputFormat * iformat
The input container format.
Definition: avformat.h:1284
as in Berlin toast format
Definition: avcodec.h:442
int channels
number of audio channels
Definition: avcodec.h:2262
void * priv_data
Format private data.
Definition: avformat.h:1300
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:628
int stream_index
Definition: avcodec.h:1424
#define AV_CH_LAYOUT_MONO
This structure stores compressed data.
Definition: avcodec.h:1399
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1415