gsmdec.c
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1 /*
2  * RAW GSM demuxer
3  * Copyright (c) 2011 Justin Ruggles
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; 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 {
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->size = ret;
52  pkt->duration = 1;
53  pkt->pts = pkt->pos / GSM_BLOCK_SIZE;
54 
55  return 0;
56 }
57 
59 {
62  if (!st)
63  return AVERROR(ENOMEM);
64 
67  st->codec->channels = 1;
69  st->codec->sample_rate = c->sample_rate;
71 
73 
74  return 0;
75 }
76 
77 static const AVOption options[] = {
78  { "sample_rate", "", offsetof(GSMDemuxerContext, sample_rate),
79  AV_OPT_TYPE_INT, {.i64 = GSM_SAMPLE_RATE}, 1, INT_MAX / GSM_BLOCK_SIZE,
81  { NULL },
82 };
83 
84 static const AVClass class = {
85  .class_name = "gsm demuxer",
86  .item_name = av_default_item_name,
87  .option = options,
89 };
90 
92  .name = "gsm",
93  .long_name = NULL_IF_CONFIG_SMALL("raw GSM"),
94  .priv_data_size = sizeof(GSMDemuxerContext),
98  .extensions = "gsm",
99  .raw_codec_id = AV_CODEC_ID_GSM,
100  .priv_class = &class,
101 };
int size
void av_free_packet(AVPacket *pkt)
Free a packet.
Definition: avpacket.c:153
AVOption.
Definition: opt.h:233
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:940
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:3283
static const AVOption options[]
Definition: gsmdec.c:77
int size
Definition: avcodec.h:916
Format I/O context.
Definition: avformat.h:828
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:38
AVOptions.
#define GSM_BLOCK_SIZE
Definition: gsmdec.c:28
static int flags
Definition: log.c:42
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:218
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:219
int duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:937
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:88
AVStream * avformat_new_stream(AVFormatContext *s, AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:2736
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:2165
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:641
int bit_rate
the average bitrate
Definition: avcodec.h:1404
audio channel layout utility functions
#define GSM_SAMPLE_RATE
Definition: gsmdec.c:30
LIBAVUTIL_VERSION_INT
Definition: eval.c:52
static int gsm_read_header(AVFormatContext *s)
Definition: gsmdec.c:58
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:536
Stream structure.
Definition: avformat.h:622
NULL
Definition: eval.c:52
enum AVMediaType codec_type
Definition: avcodec.h:1347
enum AVCodecID codec_id
Definition: avcodec.h:1350
int sample_rate
samples per second
Definition: avcodec.h:2104
AVIOContext * pb
I/O context.
Definition: avformat.h:861
av_default_item_name
Definition: dnxhdenc.c:43
#define GSM_BLOCK_SAMPLES
Definition: gsmdec.c:29
static int read_packet(AVFormatContext *ctx, AVPacket *pkt)
Definition: libcdio.c:114
Describe the class of an AVClass context structure.
Definition: log.h:33
AVInputFormat ff_gsm_demuxer
Definition: gsmdec.c:91
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:494
Main libavformat public API header.
struct AVInputFormat * iformat
Can only be iformat or oformat, not both at the same time.
Definition: avformat.h:841
as in Berlin toast format
Definition: avcodec.h:365
int channels
number of audio channels
Definition: avcodec.h:2105
void * priv_data
Format private data.
Definition: avformat.h:848
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:455
int stream_index
Definition: avcodec.h:917
#define AV_CH_LAYOUT_MONO
This structure stores compressed data.
Definition: avcodec.h:898
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:908