FFmpeg  2.1.1
gsmdec.c
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1 /*
2  * gsm 06.10 decoder
3  * Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
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 /**
23  * @file
24  * GSM decoder
25  */
26 
27 #include "libavutil/channel_layout.h"
28 #include "avcodec.h"
29 #include "get_bits.h"
30 #include "internal.h"
31 #include "msgsmdec.h"
32 
33 #include "gsmdec_template.c"
34 
35 static av_cold int gsm_init(AVCodecContext *avctx)
36 {
37  if (avctx->codec_tag == 0x0032 &&
38  avctx->bit_rate != 13000 &&
39  avctx->bit_rate != 17912 &&
40  avctx->bit_rate != 35824 &&
41  avctx->bit_rate != 71656) {
42  av_log(avctx, AV_LOG_ERROR, "Unsupported audio mode\n");
43  return AVERROR_PATCHWELCOME;
44  }
45  avctx->channels = 1;
47  if (!avctx->sample_rate)
48  avctx->sample_rate = 8000;
50 
51  switch (avctx->codec_id) {
52  case AV_CODEC_ID_GSM:
53  avctx->frame_size = GSM_FRAME_SIZE;
54  avctx->block_align = GSM_BLOCK_SIZE;
55  break;
56  case AV_CODEC_ID_GSM_MS:
57  avctx->frame_size = 2 * GSM_FRAME_SIZE;
59  }
60 
61  return 0;
62 }
63 
64 static int gsm_decode_frame(AVCodecContext *avctx, void *data,
65  int *got_frame_ptr, AVPacket *avpkt)
66 {
67  AVFrame *frame = data;
68  int res;
69  GetBitContext gb;
70  const uint8_t *buf = avpkt->data;
71  int buf_size = avpkt->size;
72  int16_t *samples;
73 
74  if (buf_size < avctx->block_align) {
75  av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
76  return AVERROR_INVALIDDATA;
77  }
78 
79  /* get output buffer */
80  frame->nb_samples = avctx->frame_size;
81  if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
82  return res;
83  samples = (int16_t *)frame->data[0];
84 
85  switch (avctx->codec_id) {
86  case AV_CODEC_ID_GSM:
87  init_get_bits(&gb, buf, buf_size * 8);
88  if (get_bits(&gb, 4) != 0xd)
89  av_log(avctx, AV_LOG_WARNING, "Missing GSM magic!\n");
90  res = gsm_decode_block(avctx, samples, &gb);
91  if (res < 0)
92  return res;
93  break;
94  case AV_CODEC_ID_GSM_MS:
95  res = ff_msgsm_decode_block(avctx, samples, buf);
96  if (res < 0)
97  return res;
98  }
99 
100  *got_frame_ptr = 1;
101 
102  return avctx->block_align;
103 }
104 
105 static void gsm_flush(AVCodecContext *avctx)
106 {
107  GSMContext *s = avctx->priv_data;
108  memset(s, 0, sizeof(*s));
109 }
110 
111 #if CONFIG_GSM_DECODER
112 AVCodec ff_gsm_decoder = {
113  .name = "gsm",
114  .long_name = NULL_IF_CONFIG_SMALL("GSM"),
115  .type = AVMEDIA_TYPE_AUDIO,
116  .id = AV_CODEC_ID_GSM,
117  .priv_data_size = sizeof(GSMContext),
118  .init = gsm_init,
120  .flush = gsm_flush,
121  .capabilities = CODEC_CAP_DR1,
122 };
123 #endif
124 #if CONFIG_GSM_MS_DECODER
125 AVCodec ff_gsm_ms_decoder = {
126  .name = "gsm_ms",
127  .long_name = NULL_IF_CONFIG_SMALL("GSM Microsoft variant"),
128  .type = AVMEDIA_TYPE_AUDIO,
129  .id = AV_CODEC_ID_GSM_MS,
130  .priv_data_size = sizeof(GSMContext),
131  .init = gsm_init,
133  .flush = gsm_flush,
134  .capabilities = CODEC_CAP_DR1,
135 };
136 #endif
const char * s
Definition: avisynth_c.h:668
#define AVERROR_PATCHWELCOME
#define GSM_FRAME_SIZE
Definition: gsm.h:29
This structure describes decoded (raw) audio or video data.
Definition: frame.h:96
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:255
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: avcodec.h:4153
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
int size
Definition: avcodec.h:1064
void av_log(void *avcl, int level, const char *fmt,...) av_printf_format(3
Send the specified message to the log if the level is less than or equal to the current av_log_level...
AVCodec.
Definition: avcodec.h:2922
#define av_cold
Definition: avcodec.h:653
int block_align
number of bytes per packet if constant and known or 0 Used by some WAV based audio codecs...
Definition: avcodec.h:1910
static uint8_t * res
Definition: ffhash.c:43
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:1881
uint8_t
const char * name
Name of the codec implementation.
Definition: avcodec.h:2929
#define GSM_MS_BLOCK_SIZE
Definition: gsm.h:26
#define CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:742
#define GSM_BLOCK_SIZE
Definition: gsm.h:25
const char data[16]
Definition: mxf.c:68
bitstream reader API header.
static void gsm_flush(AVCodecContext *avctx)
Definition: gsmdec.c:105
GSM decoder.
signed 16 bits
Definition: samplefmt.h:52
static AVFrame * frame
Definition: demuxing.c:51
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: avcodec.h:4147
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:151
Libavcodec external API header.
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:1934
int bit_rate
the average bitrate
Definition: avcodec.h:1204
static av_cold int gsm_init(AVCodecContext *avctx)
Definition: gsmdec.c:35
static void flush(AVCodecContext *avctx)
Definition: aacdec.c:498
int frame_size
Number of samples per channel in an audio frame.
Definition: avcodec.h:1893
enum AVCodecID codec_id
Definition: avcodec.h:1157
int sample_rate
samples per second
Definition: avcodec.h:1873
main external API structure.
Definition: avcodec.h:1146
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: utils.c:941
unsigned int codec_tag
fourcc (LSB first, so &quot;ABCD&quot; -&gt; (&#39;D&#39;&lt;&lt;24) + (&#39;C&#39;&lt;&lt;16) + (&#39;B&#39;&lt;&lt;8) + &#39;A&#39;).
Definition: avcodec.h:1172
void * buf
Definition: avisynth_c.h:594
uint8_t * data
Definition: avcodec.h:1063
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:405
static int gsm_decode_block(AVCodecContext *avctx, int16_t *samples, GetBitContext *gb)
void * priv_data
Definition: avcodec.h:1182
common internal api header.
static int gsm_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
Definition: gsmdec.c:64
#define AVERROR_INVALIDDATA
as in Berlin toast format
Definition: avcodec.h:415
int channels
number of audio channels
Definition: avcodec.h:1874
static int decode(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: crystalhd.c:868
#define AV_CH_LAYOUT_MONO
int ff_msgsm_decode_block(AVCodecContext *avctx, int16_t *samples, const uint8_t *buf)
Definition: msgsmdec.c:28
This structure stores compressed data.
Definition: avcodec.h:1040
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:150
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:107