FFmpeg
libgsmenc.c
Go to the documentation of this file.
1 /*
2  * Interface to libgsm for GSM encoding
3  * Copyright (c) 2005 Alban Bedel <albeu@free.fr>
4  * Copyright (c) 2006, 2007 Michel Bardiaux <mbardiaux@mediaxim.be>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 /**
24  * @file
25  * Interface to libgsm for GSM encoding
26  */
27 
28 // The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html
29 
30 #include "config.h"
31 #if HAVE_GSM_H
32 #include <gsm.h>
33 #else
34 #include <gsm/gsm.h>
35 #endif
36 
37 #include "libavutil/common.h"
38 
39 #include "avcodec.h"
40 #include "internal.h"
41 #include "gsm.h"
42 
44  gsm_destroy(avctx->priv_data);
45  avctx->priv_data = NULL;
46  return 0;
47 }
48 
50  if (avctx->channels > 1) {
51  av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
52  avctx->channels);
53  return -1;
54  }
55 
56  if (avctx->sample_rate != 8000) {
57  av_log(avctx, AV_LOG_ERROR, "Sample rate 8000Hz required for GSM, got %dHz\n",
58  avctx->sample_rate);
60  return -1;
61  }
62  if (avctx->bit_rate != 13000 /* Official */ &&
63  avctx->bit_rate != 13200 /* Very common */ &&
64  avctx->bit_rate != 0 /* Unknown; a.o. mov does not set bitrate when decoding */ ) {
65  av_log(avctx, AV_LOG_ERROR, "Bitrate 13000bps required for GSM, got %"PRId64"bps\n",
66  avctx->bit_rate);
68  return -1;
69  }
70 
71  avctx->priv_data = gsm_create();
72  if (!avctx->priv_data)
73  goto error;
74 
75  switch(avctx->codec_id) {
76  case AV_CODEC_ID_GSM:
77  avctx->frame_size = GSM_FRAME_SIZE;
78  avctx->block_align = GSM_BLOCK_SIZE;
79  break;
80  case AV_CODEC_ID_GSM_MS: {
81  int one = 1;
82  gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one);
83  avctx->frame_size = 2*GSM_FRAME_SIZE;
85  }
86  }
87 
88  return 0;
89 error:
90  libgsm_encode_close(avctx);
91  return -1;
92 }
93 
94 static int libgsm_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
95  const AVFrame *frame, int *got_packet_ptr)
96 {
97  int ret;
98  gsm_signal *samples = (gsm_signal *)frame->data[0];
99  struct gsm_state *state = avctx->priv_data;
100 
101  if ((ret = ff_alloc_packet2(avctx, avpkt, avctx->block_align, 0)) < 0)
102  return ret;
103 
104  switch(avctx->codec_id) {
105  case AV_CODEC_ID_GSM:
106  gsm_encode(state, samples, avpkt->data);
107  break;
108  case AV_CODEC_ID_GSM_MS:
109  gsm_encode(state, samples, avpkt->data);
110  gsm_encode(state, samples + GSM_FRAME_SIZE, avpkt->data + 32);
111  }
112 
113  *got_packet_ptr = 1;
114  return 0;
115 }
116 
117 static const AVCodecDefault libgsm_defaults[] = {
118  { "b", "13000" },
119  { NULL },
120 };
121 
122 #if CONFIG_LIBGSM_ENCODER
124  .name = "libgsm",
125  .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
126  .type = AVMEDIA_TYPE_AUDIO,
127  .id = AV_CODEC_ID_GSM,
128  .init = libgsm_encode_init,
129  .encode2 = libgsm_encode_frame,
130  .close = libgsm_encode_close,
131  .defaults = libgsm_defaults,
132  .channel_layouts= (const uint64_t[]) { AV_CH_LAYOUT_MONO, 0 },
133  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
135  .wrapper_name = "libgsm",
136 };
137 #endif
138 #if CONFIG_LIBGSM_MS_ENCODER
140  .name = "libgsm_ms",
141  .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
142  .type = AVMEDIA_TYPE_AUDIO,
143  .id = AV_CODEC_ID_GSM_MS,
144  .init = libgsm_encode_init,
145  .encode2 = libgsm_encode_frame,
146  .close = libgsm_encode_close,
147  .defaults = libgsm_defaults,
148  .channel_layouts= (const uint64_t[]) { AV_CH_LAYOUT_MONO, 0 },
149  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
151  .wrapper_name = "libgsm",
152 };
153 #endif
#define NULL
Definition: coverity.c:32
#define GSM_FRAME_SIZE
Definition: gsm.h:30
This structure describes decoded (raw) audio or video data.
Definition: frame.h:268
int64_t bit_rate
the average bitrate
Definition: avcodec.h:1615
AVCodec.
Definition: avcodec.h:3477
int block_align
number of bytes per packet if constant and known or 0 Used by some WAV based audio codecs...
Definition: avcodec.h:2258
int ff_alloc_packet2(AVCodecContext *avctx, AVPacket *avpkt, int64_t size, int64_t min_size)
Check AVPacket size and/or allocate data.
Definition: encode.c:32
#define av_cold
Definition: attributes.h:82
#define GSM_MS_BLOCK_SIZE
Definition: gsm.h:26
#define GSM_BLOCK_SIZE
Definition: gsm.h:25
uint8_t * data
Definition: avcodec.h:1477
static av_cold int libgsm_encode_init(AVCodecContext *avctx)
Definition: libgsmenc.c:49
#define av_log(a,...)
#define FF_COMPLIANCE_UNOFFICIAL
Allow unofficial extensions.
Definition: avcodec.h:2628
#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:3484
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
static void error(const char *err)
if(ret)
int frame_size
Number of samples per channel in an audio frame.
Definition: avcodec.h:2241
AVCodec ff_libgsm_encoder
Libavcodec external API header.
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
enum AVCodecID codec_id
Definition: avcodec.h:1575
int sample_rate
samples per second
Definition: avcodec.h:2221
main external API structure.
Definition: avcodec.h:1565
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:282
static int libgsm_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
Definition: libgsmenc.c:94
common internal api header.
common internal and external API header
signed 16 bits
Definition: samplefmt.h:61
void * priv_data
Definition: avcodec.h:1592
static const AVCodecDefault libgsm_defaults[]
Definition: libgsmenc.c:117
as in Berlin toast format
Definition: avcodec.h:582
AVCodec ff_libgsm_ms_encoder
int channels
number of audio channels
Definition: avcodec.h:2222
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:1454
int strict_std_compliance
strictly follow the standard (MPEG-4, ...).
Definition: avcodec.h:2624
static av_cold int libgsm_encode_close(AVCodecContext *avctx)
Definition: libgsmenc.c:43
static struct @308 state