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/*
* Interface to libgsm for GSM decoding
* Copyright (c) 2005 Alban Bedel <albeu@free.fr>
* Copyright (c) 2006, 2007 Michel Bardiaux <mbardiaux@mediaxim.be>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Interface to libgsm for GSM decoding
*/
// The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html
#include "config.h"
#if HAVE_GSM_H
#include <gsm.h>
#else
#include <gsm/gsm.h>
#endif
#include "libavutil/channel_layout.h"
#include "libavutil/common.h"
#include "avcodec.h"
#include "internal.h"
#include "gsm.h"
typedef struct LibGSMDecodeContext {
struct gsm_state *state;
} LibGSMDecodeContext;
static av_cold int libgsm_decode_init(AVCodecContext *avctx) {
LibGSMDecodeContext *s = avctx->priv_data;
avctx->channels = 1;
avctx->channel_layout = AV_CH_LAYOUT_MONO;
if (!avctx->sample_rate)
avctx->sample_rate = 8000;
avctx->sample_fmt = AV_SAMPLE_FMT_S16;
s->state = gsm_create();
switch(avctx->codec_id) {
case AV_CODEC_ID_GSM:
avctx->frame_size = GSM_FRAME_SIZE;
avctx->block_align = GSM_BLOCK_SIZE;
break;
case AV_CODEC_ID_GSM_MS: {
int one = 1;
gsm_option(s->state, GSM_OPT_WAV49, &one);
avctx->frame_size = 2 * GSM_FRAME_SIZE;
avctx->block_align = GSM_MS_BLOCK_SIZE;
}
}
return 0;
}
static av_cold int libgsm_decode_close(AVCodecContext *avctx) {
LibGSMDecodeContext *s = avctx->priv_data;
gsm_destroy(s->state);
s->state = NULL;
return 0;
}
static int libgsm_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame_ptr, AVPacket *avpkt)
{
int i, ret;
LibGSMDecodeContext *s = avctx->priv_data;
AVFrame *frame = data;
uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
int16_t *samples;
if (buf_size < avctx->block_align) {
av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
return AVERROR_INVALIDDATA;
}
/* get output buffer */
frame->nb_samples = avctx->frame_size;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
samples = (int16_t *)frame->data[0];
for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) {
if ((ret = gsm_decode(s->state, buf, samples)) < 0)
return -1;
buf += GSM_BLOCK_SIZE;
samples += GSM_FRAME_SIZE;
}
*got_frame_ptr = 1;
return avctx->block_align;
}
static void libgsm_flush(AVCodecContext *avctx) {
LibGSMDecodeContext *s = avctx->priv_data;
int one = 1;
gsm_destroy(s->state);
s->state = gsm_create();
if (avctx->codec_id == AV_CODEC_ID_GSM_MS)
gsm_option(s->state, GSM_OPT_WAV49, &one);
}
#if CONFIG_LIBGSM_DECODER
AVCodec ff_libgsm_decoder = {
.name = "libgsm",
.long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_GSM,
.priv_data_size = sizeof(LibGSMDecodeContext),
.init = libgsm_decode_init,
.close = libgsm_decode_close,
.decode = libgsm_decode_frame,
.flush = libgsm_flush,
.capabilities = CODEC_CAP_DR1,
};
#endif
#if CONFIG_LIBGSM_MS_DECODER
AVCodec ff_libgsm_ms_decoder = {
.name = "libgsm_ms",
.long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_GSM_MS,
.priv_data_size = sizeof(LibGSMDecodeContext),
.init = libgsm_decode_init,
.close = libgsm_decode_close,
.decode = libgsm_decode_frame,
.flush = libgsm_flush,
.capabilities = CODEC_CAP_DR1,
};
#endif
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