FFmpeg  2.1.1
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 
22 #include "libavutil/channel_layout.h"
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->duration = 1;
52  pkt->pts = pkt->pos / GSM_BLOCK_SIZE;
53 
54  return 0;
55 }
56 
58 {
60  AVStream *st = avformat_new_stream(s, NULL);
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 };
const char * s
Definition: avisynth_c.h:668
int size
void av_free_packet(AVPacket *pkt)
Free a packet.
Definition: avpacket.c:279
AVOption.
Definition: opt.h:253
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:478
#define LIBAVUTIL_VERSION_INT
Definition: avcodec.h:820
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1092
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:3922
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:686
Format I/O context.
Definition: avformat.h:968
const char * av_default_item_name(void *ctx)
Return the context name.
Definition: log.c:145
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:55
#define GSM_BLOCK_SIZE
Definition: gsmdec.c:28
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:248
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:3348
int duration
Duration of this packet in AVStream-&gt;time_base units, 0 if unknown.
Definition: avcodec.h:1085
const OptionDef options[]
Definition: ffserver.c:4682
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:200
void * priv_data
Format private data.
Definition: avformat.h:988
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:151
static const AVClass gsm_class
Definition: gsmdec.c:83
struct AVInputFormat * iformat
Can only be iformat or oformat, not both at the same time.
Definition: avformat.h:981
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:355
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:1934
int bit_rate
the average bitrate
Definition: avcodec.h:1204
ret
Definition: avfilter.c:961
#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:592
Stream structure.
Definition: avformat.h:667
sample_rate
enum AVMediaType codec_type
Definition: avcodec.h:1154
enum AVCodecID codec_id
Definition: avcodec.h:1157
int sample_rate
samples per second
Definition: avcodec.h:1873
#define GSM_BLOCK_SAMPLES
Definition: gsmdec.c:29
AVIOContext * pb
I/O context.
Definition: avformat.h:1001
static int read_packet(AVFormatContext *ctx, AVPacket *pkt)
Definition: libcdio.c:114
Describe the class of an AVClass context structure.
Definition: log.h:50
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:517
static int flags
Definition: cpu.c:45
#define AV_OPT_FLAG_DECODING_PARAM
a generic parameter which can be set by the user for demuxing or decoding
Definition: opt.h:284
static double c[64]
Main libavformat public API header.
as in Berlin toast format
Definition: avcodec.h:415
int channels
number of audio channels
Definition: avcodec.h:1874
#define AVERROR(e)
static AVPacket pkt
Definition: demuxing.c:52
int stream_index
Definition: avcodec.h:1065
#define AV_CH_LAYOUT_MONO
This structure stores compressed data.
Definition: avcodec.h:1040
int64_t pts
Presentation timestamp in AVStream-&gt;time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1056