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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 
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  avctx->channels = 1;
39  if (!avctx->sample_rate)
40  avctx->sample_rate = 8000;
42 
43  switch (avctx->codec_id) {
44  case AV_CODEC_ID_GSM:
45  avctx->frame_size = GSM_FRAME_SIZE;
46  avctx->block_align = GSM_BLOCK_SIZE;
47  break;
48  case AV_CODEC_ID_GSM_MS:
49  avctx->frame_size = 2 * GSM_FRAME_SIZE;
50  if (!avctx->block_align)
52  else
53  if (avctx->block_align < MSN_MIN_BLOCK_SIZE ||
54  avctx->block_align > GSM_MS_BLOCK_SIZE ||
55  (avctx->block_align - MSN_MIN_BLOCK_SIZE) % 3) {
56  av_log(avctx, AV_LOG_ERROR, "Invalid block alignment %d\n",
57  avctx->block_align);
58  return AVERROR_INVALIDDATA;
59  }
60  }
61 
62  return 0;
63 }
64 
65 static int gsm_decode_frame(AVCodecContext *avctx, void *data,
66  int *got_frame_ptr, AVPacket *avpkt)
67 {
68  AVFrame *frame = data;
69  int res;
70  GetBitContext gb;
71  const uint8_t *buf = avpkt->data;
72  int buf_size = avpkt->size;
73  int16_t *samples;
74 
75  if (buf_size < avctx->block_align) {
76  av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
77  return AVERROR_INVALIDDATA;
78  }
79 
80  /* get output buffer */
81  frame->nb_samples = avctx->frame_size;
82  if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
83  return res;
84  samples = (int16_t *)frame->data[0];
85 
86  switch (avctx->codec_id) {
87  case AV_CODEC_ID_GSM:
88  init_get_bits(&gb, buf, buf_size * 8);
89  if (get_bits(&gb, 4) != 0xd)
90  av_log(avctx, AV_LOG_WARNING, "Missing GSM magic!\n");
91  res = gsm_decode_block(avctx, samples, &gb, GSM_13000);
92  if (res < 0)
93  return res;
94  break;
95  case AV_CODEC_ID_GSM_MS:
96  res = ff_msgsm_decode_block(avctx, samples, buf,
97  (GSM_MS_BLOCK_SIZE - avctx->block_align) / 3);
98  if (res < 0)
99  return res;
100  }
101 
102  *got_frame_ptr = 1;
103 
104  return avctx->block_align;
105 }
106 
107 static void gsm_flush(AVCodecContext *avctx)
108 {
109  GSMContext *s = avctx->priv_data;
110  memset(s, 0, sizeof(*s));
111 }
112 
113 #if CONFIG_GSM_DECODER
114 AVCodec ff_gsm_decoder = {
115  .name = "gsm",
116  .long_name = NULL_IF_CONFIG_SMALL("GSM"),
117  .type = AVMEDIA_TYPE_AUDIO,
118  .id = AV_CODEC_ID_GSM,
119  .priv_data_size = sizeof(GSMContext),
120  .init = gsm_init,
122  .flush = gsm_flush,
123  .capabilities = AV_CODEC_CAP_DR1,
124 };
125 #endif
126 #if CONFIG_GSM_MS_DECODER
127 AVCodec ff_gsm_ms_decoder = {
128  .name = "gsm_ms",
129  .long_name = NULL_IF_CONFIG_SMALL("GSM Microsoft variant"),
130  .type = AVMEDIA_TYPE_AUDIO,
131  .id = AV_CODEC_ID_GSM_MS,
132  .priv_data_size = sizeof(GSMContext),
133  .init = gsm_init,
135  .flush = gsm_flush,
136  .capabilities = AV_CODEC_CAP_DR1,
137 };
138 #endif
const char * s
Definition: avisynth_c.h:631
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
#define GSM_FRAME_SIZE
Definition: gsm.h:30
This structure describes decoded (raw) audio or video data.
Definition: frame.h:180
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
static void flush(AVCodecContext *avctx)
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:260
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
int size
Definition: avcodec.h:1575
AVCodec.
Definition: avcodec.h:3531
int block_align
number of bytes per packet if constant and known or 0 Used by some WAV based audio codecs...
Definition: avcodec.h:2437
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:2408
uint8_t
#define av_cold
Definition: attributes.h:82
#define GSM_BLOCK_SIZE
Definition: gsmdec.c:28
#define GSM_MS_BLOCK_SIZE
Definition: gsm.h:26
Definition: gsm.h:33
static AVFrame * frame
uint8_t * data
Definition: avcodec.h:1574
bitstream reader API header.
static int gsm_decode_block(AVCodecContext *avctx, int16_t *samples, GetBitContext *gb, int mode)
static void gsm_flush(AVCodecContext *avctx)
Definition: gsmdec.c:107
#define av_log(a,...)
int ff_msgsm_decode_block(AVCodecContext *avctx, int16_t *samples, const uint8_t *buf, int mode)
Definition: msgsmdec.c:28
GSM decoder.
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
const char * name
Name of the codec implementation.
Definition: avcodec.h:3538
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:2451
audio channel layout utility functions
static av_cold int gsm_init(AVCodecContext *avctx)
Definition: gsmdec.c:35
int frame_size
Number of samples per channel in an audio frame.
Definition: avcodec.h:2420
Libavcodec external API header.
enum AVCodecID codec_id
Definition: avcodec.h:1656
int sample_rate
samples per second
Definition: avcodec.h:2400
main external API structure.
Definition: avcodec.h:1639
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: utils.c:928
void * buf
Definition: avisynth_c.h:553
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:418
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:194
static int decode(AVCodecContext *avctx, void *data, int *got_sub, AVPacket *avpkt)
Definition: ccaption_dec.c:722
common internal api header.
signed 16 bits
Definition: samplefmt.h:61
static int gsm_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
Definition: gsmdec.c:65
void * priv_data
Definition: avcodec.h:1681
as in Berlin toast format
Definition: avcodec.h:527
int channels
number of audio channels
Definition: avcodec.h:2401
#define MSN_MIN_BLOCK_SIZE
Definition: gsm.h:27
#define AV_CH_LAYOUT_MONO
This structure stores compressed data.
Definition: avcodec.h:1551
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:237
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:950