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 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 
27 #include "avcodec.h"
28 #include "internal.h"
29 #include "get_bits.h"
30 #include "msgsmdec.h"
31 
32 #include "gsmdec_template.c"
33 
34 static av_cold int gsm_init(AVCodecContext *avctx)
35 {
36  GSMContext *s = avctx->priv_data;
37 
38  avctx->channels = 1;
39  if (!avctx->sample_rate)
40  avctx->sample_rate = 8000;
42 
43  switch (avctx->codec_id) {
44  case CODEC_ID_GSM:
45  avctx->frame_size = GSM_FRAME_SIZE;
46  avctx->block_align = GSM_BLOCK_SIZE;
47  break;
48  case CODEC_ID_GSM_MS:
49  avctx->frame_size = 2 * GSM_FRAME_SIZE;
51  }
52 
54  avctx->coded_frame = &s->frame;
55 
56  return 0;
57 }
58 
59 static int gsm_decode_frame(AVCodecContext *avctx, void *data,
60  int *got_frame_ptr, AVPacket *avpkt)
61 {
62  GSMContext *s = avctx->priv_data;
63  int res;
64  GetBitContext gb;
65  const uint8_t *buf = avpkt->data;
66  int buf_size = avpkt->size;
67  int16_t *samples;
68 
69  if (buf_size < avctx->block_align) {
70  av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
71  return AVERROR_INVALIDDATA;
72  }
73 
74  /* get output buffer */
75  s->frame.nb_samples = avctx->frame_size;
76  if ((res = ff_get_buffer(avctx, &s->frame)) < 0) {
77  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
78  return res;
79  }
80  samples = (int16_t *)s->frame.data[0];
81 
82  switch (avctx->codec_id) {
83  case CODEC_ID_GSM:
84  init_get_bits(&gb, buf, buf_size * 8);
85  if (get_bits(&gb, 4) != 0xd)
86  av_log(avctx, AV_LOG_WARNING, "Missing GSM magic!\n");
87  res = gsm_decode_block(avctx, samples, &gb);
88  if (res < 0)
89  return res;
90  break;
91  case CODEC_ID_GSM_MS:
92  res = ff_msgsm_decode_block(avctx, samples, buf);
93  if (res < 0)
94  return res;
95  }
96 
97  *got_frame_ptr = 1;
98  *(AVFrame *)data = s->frame;
99 
100  return avctx->block_align;
101 }
102 
103 static void gsm_flush(AVCodecContext *avctx)
104 {
105  GSMContext *s = avctx->priv_data;
106  memset(s, 0, sizeof(*s));
107 }
108 
110  .name = "gsm",
111  .type = AVMEDIA_TYPE_AUDIO,
112  .id = CODEC_ID_GSM,
113  .priv_data_size = sizeof(GSMContext),
114  .init = gsm_init,
116  .flush = gsm_flush,
117  .capabilities = CODEC_CAP_DR1,
118  .long_name = NULL_IF_CONFIG_SMALL("GSM"),
119 };
120 
122  .name = "gsm_ms",
123  .type = AVMEDIA_TYPE_AUDIO,
124  .id = CODEC_ID_GSM_MS,
125  .priv_data_size = sizeof(GSMContext),
126  .init = gsm_init,
128  .flush = gsm_flush,
129  .capabilities = CODEC_CAP_DR1,
130  .long_name = NULL_IF_CONFIG_SMALL("GSM Microsoft variant"),
131 };
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:54
#define GSM_FRAME_SIZE
Definition: gsm.h:29
Audio Video Frame.
Definition: avcodec.h:985
static short * samples
Definition: ffmpeg.c:233
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:237
AVFrame * coded_frame
the picture in the bitstream
Definition: avcodec.h:2000
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:117
int size
Definition: avcodec.h:909
signed 16 bits
Definition: samplefmt.h:30
AVCodec.
Definition: avcodec.h:3189
int block_align
number of bytes per packet if constant and known or 0 Used by some WAV based audio codecs...
Definition: avcodec.h:1751
static int decode(MimicContext *ctx, int quality, int num_coeffs, int is_iframe)
Definition: mimic.c:228
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:1464
#define av_cold
Definition: attributes.h:71
#define GSM_BLOCK_SIZE
Definition: gsmdec.c:27
#define GSM_MS_BLOCK_SIZE
Definition: gsm.h:26
const char data[16]
Definition: mxf.c:60
uint8_t * data
Definition: avcodec.h:908
bitstream reader API header.
static void gsm_flush(AVCodecContext *avctx)
Definition: gsmdec.c:103
static int init(AVCodecParserContext *s)
Definition: h264_parser.c:336
GSM decoder.
#define CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:719
AVCodec ff_gsm_decoder
Definition: gsmdec.c:109
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:191
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:140
const char * name
Name of the codec implementation.
Definition: avcodec.h:3196
AVCodec ff_gsm_ms_decoder
Definition: gsmdec.c:121
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame)
Definition: utils.c:1867
static av_cold int gsm_init(AVCodecContext *avctx)
Definition: gsmdec.c:34
as in Berlin toast format
Definition: avcodec.h:357
int frame_size
Samples per packet, initialized when calling 'init'.
Definition: avcodec.h:1470
external API header
int sample_rate
samples per second
Definition: avcodec.h:1456
main external API structure.
Definition: avcodec.h:1329
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:111
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:354
static int gsm_decode_block(AVCodecContext *avctx, int16_t *samples, GetBitContext *gb)
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: avcodec.h:997
AVFrame frame
Definition: gsmdec_data.h:29
common internal api header.
static av_cold void flush(AVCodecContext *avctx)
Flush (reset) the frame ID after seeking.
Definition: alsdec.c:1779
static int gsm_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
Definition: gsmdec.c:59
void * priv_data
Definition: avcodec.h:1531
int channels
number of audio channels
Definition: avcodec.h:1457
void avcodec_get_frame_defaults(AVFrame *pic)
Set the fields of the given AVFrame to default values.
Definition: utils.c:609
int ff_msgsm_decode_block(AVCodecContext *avctx, int16_t *samples, const uint8_t *buf)
Definition: msgsmdec.c:28
int nb_samples
number of audio samples (per channel) described by this frame
Definition: avcodec.h:1265
enum CodecID codec_id
Definition: avcodec.h:1575