96 lines
2.4 KiB
C
96 lines
2.4 KiB
C
/*
|
|
* Interface to libgsm for gsm encoding/decoding
|
|
* Copyright (c) 2005 Alban Bedel <albeu@free.fr>
|
|
*
|
|
* This library 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 of the License, or (at your option) any later version.
|
|
*
|
|
* This library 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 this library; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
/**
|
|
* @file libgsm.c
|
|
* Interface to libgsm for gsm encoding/decoding
|
|
*/
|
|
|
|
#include "avcodec.h"
|
|
#include <gsm.h>
|
|
|
|
// gsm.h miss some essential constants
|
|
#define GSM_BLOCK_SIZE 33
|
|
#define GSM_FRAME_SIZE 160
|
|
|
|
static int libgsm_init(AVCodecContext *avctx) {
|
|
if (avctx->channels > 1 || avctx->sample_rate != 8000)
|
|
return -1;
|
|
|
|
avctx->frame_size = GSM_FRAME_SIZE;
|
|
avctx->block_align = GSM_BLOCK_SIZE;
|
|
|
|
avctx->priv_data = gsm_create();
|
|
|
|
avctx->coded_frame= avcodec_alloc_frame();
|
|
avctx->coded_frame->key_frame= 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int libgsm_close(AVCodecContext *avctx) {
|
|
gsm_destroy(avctx->priv_data);
|
|
avctx->priv_data = NULL;
|
|
return 0;
|
|
}
|
|
|
|
static int libgsm_encode_frame(AVCodecContext *avctx,
|
|
unsigned char *frame, int buf_size, void *data) {
|
|
// we need a full block
|
|
if(buf_size < GSM_BLOCK_SIZE) return 0;
|
|
|
|
gsm_encode(avctx->priv_data,data,frame);
|
|
|
|
return GSM_BLOCK_SIZE;
|
|
}
|
|
|
|
|
|
AVCodec libgsm_encoder = {
|
|
"gsm",
|
|
CODEC_TYPE_AUDIO,
|
|
CODEC_ID_GSM,
|
|
0,
|
|
libgsm_init,
|
|
libgsm_encode_frame,
|
|
libgsm_close,
|
|
};
|
|
|
|
static int libgsm_decode_frame(AVCodecContext *avctx,
|
|
void *data, int *data_size,
|
|
uint8_t *buf, int buf_size) {
|
|
|
|
if(buf_size < GSM_BLOCK_SIZE) return 0;
|
|
|
|
if(gsm_decode(avctx->priv_data,buf,data)) return -1;
|
|
|
|
*data_size = GSM_FRAME_SIZE*2;
|
|
return GSM_BLOCK_SIZE;
|
|
}
|
|
|
|
AVCodec libgsm_decoder = {
|
|
"gsm",
|
|
CODEC_TYPE_AUDIO,
|
|
CODEC_ID_GSM,
|
|
0,
|
|
libgsm_init,
|
|
NULL,
|
|
libgsm_close,
|
|
libgsm_decode_frame,
|
|
};
|