FFmpeg
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
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
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
#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:295
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:100
static void flush(AVCodecContext *avctx)
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:379
#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:1481
AVCodec.
Definition: avcodec.h:3492
int block_align
number of bytes per packet if constant and known or 0 Used by some WAV based audio codecs...
Definition: avcodec.h:2265
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
AVCodec ff_gsm_decoder
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:2236
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
uint8_t * data
Definition: avcodec.h:1480
bitstream reader API header.
static int gsm_decode_block(AVCodecContext *avctx, int16_t *samples, GetBitContext *gb, int mode)
AVCodec ff_gsm_ms_decoder
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:29
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:186
const char * name
Name of the codec implementation.
Definition: avcodec.h:3499
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:2279
audio channel layout utility functions
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
#define s(width, name)
Definition: cbs_vp9.c:257
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:2248
Libavcodec external API header.
enum AVCodecID codec_id
Definition: avcodec.h:1578
int sample_rate
samples per second
Definition: avcodec.h:2228
main external API structure.
Definition: avcodec.h:1568
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1968
void * buf
Definition: avisynth_c.h:766
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:659
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
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:1595
as in Berlin toast format
Definition: avcodec.h:583
int channels
number of audio channels
Definition: avcodec.h:2229
#define MSN_MIN_BLOCK_SIZE
Definition: gsm.h:27
Filter the word “frame” indicates either a video frame or a group of audio samples
#define AV_CH_LAYOUT_MONO
This structure stores compressed data.
Definition: avcodec.h:1457
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:361
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:984