2 * Interface to libgsm for GSM decoding
3 * Copyright (c) 2005 Alban Bedel <albeu@free.fr>
4 * Copyright (c) 2006, 2007 Michel Bardiaux <mbardiaux@mediaxim.be>
6 * This file is part of FFmpeg.
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.
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.
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
25 * Interface to libgsm for GSM decoding
28 // The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html
37 #include "libavutil/channel_layout.h"
38 #include "libavutil/common.h"
44 typedef struct LibGSMDecodeContext
{
45 struct gsm_state
*state
;
46 } LibGSMDecodeContext
;
48 static av_cold
int libgsm_decode_init(AVCodecContext
*avctx
) {
49 LibGSMDecodeContext
*s
= avctx
->priv_data
;
52 avctx
->channel_layout
= AV_CH_LAYOUT_MONO
;
53 if (!avctx
->sample_rate
)
54 avctx
->sample_rate
= 8000;
55 avctx
->sample_fmt
= AV_SAMPLE_FMT_S16
;
57 s
->state
= gsm_create();
59 switch(avctx
->codec_id
) {
61 avctx
->frame_size
= GSM_FRAME_SIZE
;
62 avctx
->block_align
= GSM_BLOCK_SIZE
;
64 case AV_CODEC_ID_GSM_MS
: {
66 gsm_option(s
->state
, GSM_OPT_WAV49
, &one
);
67 avctx
->frame_size
= 2 * GSM_FRAME_SIZE
;
68 avctx
->block_align
= GSM_MS_BLOCK_SIZE
;
75 static av_cold
int libgsm_decode_close(AVCodecContext
*avctx
) {
76 LibGSMDecodeContext
*s
= avctx
->priv_data
;
78 gsm_destroy(s
->state
);
83 static int libgsm_decode_frame(AVCodecContext
*avctx
, void *data
,
84 int *got_frame_ptr
, AVPacket
*avpkt
)
87 LibGSMDecodeContext
*s
= avctx
->priv_data
;
88 AVFrame
*frame
= data
;
89 uint8_t *buf
= avpkt
->data
;
90 int buf_size
= avpkt
->size
;
93 if (buf_size
< avctx
->block_align
) {
94 av_log(avctx
, AV_LOG_ERROR
, "Packet is too small\n");
95 return AVERROR_INVALIDDATA
;
98 /* get output buffer */
99 frame
->nb_samples
= avctx
->frame_size
;
100 if ((ret
= ff_get_buffer(avctx
, frame
, 0)) < 0)
102 samples
= (int16_t *)frame
->data
[0];
104 for (i
= 0; i
< avctx
->frame_size
/ GSM_FRAME_SIZE
; i
++) {
105 if ((ret
= gsm_decode(s
->state
, buf
, samples
)) < 0)
107 buf
+= GSM_BLOCK_SIZE
;
108 samples
+= GSM_FRAME_SIZE
;
113 return avctx
->block_align
;
116 static void libgsm_flush(AVCodecContext
*avctx
) {
117 LibGSMDecodeContext
*s
= avctx
->priv_data
;
120 gsm_destroy(s
->state
);
121 s
->state
= gsm_create();
122 if (avctx
->codec_id
== AV_CODEC_ID_GSM_MS
)
123 gsm_option(s
->state
, GSM_OPT_WAV49
, &one
);
126 #if CONFIG_LIBGSM_DECODER
127 AVCodec ff_libgsm_decoder
= {
129 .long_name
= NULL_IF_CONFIG_SMALL("libgsm GSM"),
130 .type
= AVMEDIA_TYPE_AUDIO
,
131 .id
= AV_CODEC_ID_GSM
,
132 .priv_data_size
= sizeof(LibGSMDecodeContext
),
133 .init
= libgsm_decode_init
,
134 .close
= libgsm_decode_close
,
135 .decode
= libgsm_decode_frame
,
136 .flush
= libgsm_flush
,
137 .capabilities
= CODEC_CAP_DR1
,
140 #if CONFIG_LIBGSM_MS_DECODER
141 AVCodec ff_libgsm_ms_decoder
= {
143 .long_name
= NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
144 .type
= AVMEDIA_TYPE_AUDIO
,
145 .id
= AV_CODEC_ID_GSM_MS
,
146 .priv_data_size
= sizeof(LibGSMDecodeContext
),
147 .init
= libgsm_decode_init
,
148 .close
= libgsm_decode_close
,
149 .decode
= libgsm_decode_frame
,
150 .flush
= libgsm_flush
,
151 .capabilities
= CODEC_CAP_DR1
,