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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 
37 static int gsm_probe(AVProbeData *p)
38 {
39  int valid = 0, invalid = 0;
40  uint8_t *b = p->buf;
41  while (b < p->buf + p->buf_size - 32) {
42  if ((*b & 0xf0) == 0xd0) {
43  valid++;
44  } else {
45  invalid++;
46  }
47  b += 33;
48  }
49  if (valid >> 5 > invalid)
50  return AVPROBE_SCORE_EXTENSION + 1;
51  return 0;
52 }
53 
55 {
56  int ret, size;
57 
58  size = GSM_BLOCK_SIZE;
59 
60  pkt->pos = avio_tell(s->pb);
61  pkt->stream_index = 0;
62 
63  ret = av_get_packet(s->pb, pkt, size);
64  if (ret < GSM_BLOCK_SIZE) {
65  av_packet_unref(pkt);
66  return ret < 0 ? ret : AVERROR(EIO);
67  }
68  pkt->duration = 1;
69  pkt->pts = pkt->pos / GSM_BLOCK_SIZE;
70 
71  return 0;
72 }
73 
75 {
78  if (!st)
79  return AVERROR(ENOMEM);
80 
83  st->codecpar->channels = 1;
87 
89 
90  return 0;
91 }
92 
93 static const AVOption options[] = {
94  { "sample_rate", "", offsetof(GSMDemuxerContext, sample_rate),
95  AV_OPT_TYPE_INT, {.i64 = GSM_SAMPLE_RATE}, 1, INT_MAX / GSM_BLOCK_SIZE,
97  { NULL },
98 };
99 
100 static const AVClass gsm_class = {
101  .class_name = "gsm demuxer",
102  .item_name = av_default_item_name,
103  .option = options,
104  .version = LIBAVUTIL_VERSION_INT,
105 };
106 
108  .name = "gsm",
109  .long_name = NULL_IF_CONFIG_SMALL("raw GSM"),
110  .priv_data_size = sizeof(GSMDemuxerContext),
115  .extensions = "gsm",
116  .raw_codec_id = AV_CODEC_ID_GSM,
117  .priv_class = &gsm_class,
118 };
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:631
AVOption.
Definition: opt.h:245
#define LIBAVUTIL_VERSION_INT
Definition: version.h:70
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1597
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:4405
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3915
static const AVOption options[]
Definition: gsmdec.c:93
const char * b
Definition: vf_curves.c:109
static AVPacket pkt
Format I/O context.
Definition: avformat.h:1319
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
uint8_t
AVOptions.
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:1595
#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:4043
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:260
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:447
uint64_t channel_layout
Audio only.
Definition: avcodec.h:4017
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: avcodec.h:3944
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:176
static const AVClass gsm_class
Definition: gsmdec.c:100
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3911
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:462
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:461
audio channel layout utility functions
static int read_probe(AVProbeData *pd)
Definition: jvdec.c:55
static int gsm_probe(AVProbeData *p)
Definition: gsmdec.c:37
#define GSM_SAMPLE_RATE
Definition: gsmdec.c:30
static int gsm_read_header(AVFormatContext *s)
Definition: gsmdec.c:74
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:638
Stream structure.
Definition: avformat.h:876
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
sample_rate
AVIOContext * pb
I/O context.
Definition: avformat.h:1361
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:549
#define GSM_BLOCK_SAMPLES
Definition: gsmdec.c:29
void * buf
Definition: avisynth_c.h:553
Describe the class of an AVClass context structure.
Definition: log.h:67
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:485
#define AV_OPT_FLAG_DECODING_PARAM
a generic parameter which can be set by the user for demuxing or decoding
Definition: opt.h:276
AVInputFormat ff_gsm_demuxer
Definition: gsmdec.c:107
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:469
static int gsm_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: gsmdec.c:54
This structure contains the data a format has to probe a file.
Definition: avformat.h:459
int raw_codec_id
Raw demuxers store their codec ID here.
Definition: avformat.h:706
static int flags
Definition: cpu.c:47
int sample_rate
Audio only.
Definition: avcodec.h:4025
Main libavformat public API header.
static double c[64]
struct AVInputFormat * iformat
The input container format.
Definition: avformat.h:1331
as in Berlin toast format
Definition: avcodec.h:529
void * priv_data
Format private data.
Definition: avformat.h:1347
int channels
Audio only.
Definition: avcodec.h:4021
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:660
AVCodecParameters * codecpar
Definition: avformat.h:1006
int stream_index
Definition: avcodec.h:1579
#define AV_CH_LAYOUT_MONO
This structure stores compressed data.
Definition: avcodec.h:1554
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1570