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 
22 #include "libavutil/mathematics.h"
23 #include "libavutil/opt.h"
24 #include "avformat.h"
25 #include "internal.h"
26 
27 #define GSM_BLOCK_SIZE 33
28 #define GSM_BLOCK_SAMPLES 160
29 #define GSM_SAMPLE_RATE 8000
30 
31 typedef struct {
32  AVClass *class;
35 
37 {
38  int ret, size;
39 
40  size = GSM_BLOCK_SIZE;
41 
42  pkt->pos = avio_tell(s->pb);
43  pkt->stream_index = 0;
44 
45  ret = av_get_packet(s->pb, pkt, size);
46  if (ret < GSM_BLOCK_SIZE) {
47  av_free_packet(pkt);
48  return ret < 0 ? ret : AVERROR(EIO);
49  }
50  pkt->size = ret;
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 
65  st->codec->codec_id = s->iformat->value;
66  st->codec->channels = 1;
67  st->codec->sample_rate = c->sample_rate;
69 
71 
72  return 0;
73 }
74 
75 static const AVOption options[] = {
76  { "sample_rate", "", offsetof(GSMDemuxerContext, sample_rate),
77  AV_OPT_TYPE_INT, {.dbl = GSM_SAMPLE_RATE}, 1, INT_MAX / GSM_BLOCK_SIZE,
79  { NULL },
80 };
81 
82 static const AVClass class = {
83  .class_name = "gsm demuxer",
84  .item_name = av_default_item_name,
85  .option = options,
87 };
88 
90  .name = "gsm",
91  .long_name = NULL_IF_CONFIG_SMALL("raw GSM"),
92  .priv_data_size = sizeof(GSMDemuxerContext),
96  .extensions = "gsm",
97  .value = CODEC_ID_GSM,
98  .priv_class = &class,
99 };
int size
AVOption.
Definition: opt.h:244
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:933
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the pts for a given stream.
Definition: utils.c:3828
static const AVOption options[]
Definition: gsmdec.c:75
#define AV_OPT_FLAG_DECODING_PARAM
a generic parameter which can be set by the user for demuxing or decoding
Definition: opt.h:275
int size
Definition: avcodec.h:909
AVOptions.
Format I/O context.
Definition: avformat.h:863
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
#define GSM_BLOCK_SIZE
Definition: gsmdec.c:27
static int read_header(FFV1Context *f)
Definition: ffv1.c:1513
static int flags
Definition: log.c:34
void av_free_packet(AVPacket *pkt)
Free a packet.
Definition: avpacket.c:151
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:269
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:492
int duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:930
#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:191
AVStream * avformat_new_stream(AVFormatContext *s, AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:2776
AVCodecContext * codec
codec context
Definition: avformat.h:623
int bit_rate
the average bitrate
Definition: avcodec.h:1340
#define GSM_SAMPLE_RATE
Definition: gsmdec.c:29
as in Berlin toast format
Definition: avcodec.h:357
LIBAVUTIL_VERSION_INT
Definition: eval.c:50
Stream structure.
Definition: avformat.h:620
NULL
Definition: eval.c:50
enum AVMediaType codec_type
Definition: avcodec.h:1574
int value
General purpose read-only value that the format can use.
Definition: avformat.h:542
int sample_rate
samples per second
Definition: avcodec.h:1456
AVIOContext * pb
Definition: avformat.h:896
av_default_item_name
Definition: dnxhdenc.c:43
#define GSM_BLOCK_SAMPLES
Definition: gsmdec.c:28
static int gsm_read_header(AVFormatContext *s, AVFormatParameters *ap)
Definition: gsmdec.c:57
static int read_packet(AVFormatContext *ctx, AVPacket *pkt)
Definition: libcdio.c:109
Describe the class of an AVClass context structure.
Definition: log.h:33
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:376
AVInputFormat ff_gsm_demuxer
Definition: gsmdec.c:89
static int gsm_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: gsmdec.c:36
Main libavformat public API header.
struct AVInputFormat * iformat
Can only be iformat or oformat, not both at the same time.
Definition: avformat.h:876
int channels
number of audio channels
Definition: avcodec.h:1457
void * priv_data
Format private data.
Definition: avformat.h:883
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:460
int stream_index
Definition: avcodec.h:910
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:901
enum CodecID codec_id
Definition: avcodec.h:1575