/*
* Interface to libgsm for gsm encoding/decoding
* Copyright (c) 2005 Alban Bedel <albeu@free.fr>
+ * Copyright (c) 2006, 2007 Michel Bardiaux <mbardiaux@mediaxim.be>
*
- * This library is free software; you can redistribute it and/or
+ * 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 of the License, or (at your option) any later version.
+ * version 2.1 of the License, or (at your option) any later version.
*
- * This library is distributed in the hope that it will be useful,
+ * 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 this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* Interface to libgsm for gsm encoding/decoding
*/
+// The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html
+
#include "avcodec.h"
#include <gsm.h>
-// gsm.h miss some essential constants
+// gsm.h misses some essential constants
#define GSM_BLOCK_SIZE 33
+#define GSM_MS_BLOCK_SIZE 65
#define GSM_FRAME_SIZE 160
static int libgsm_init(AVCodecContext *avctx) {
- if (avctx->channels > 1 || avctx->sample_rate != 8000)
+ if (avctx->channels > 1 || avctx->sample_rate != 8000 || avctx->bit_rate != 13000)
return -1;
- avctx->frame_size = GSM_FRAME_SIZE;
- avctx->block_align = GSM_BLOCK_SIZE;
-
avctx->priv_data = gsm_create();
+ switch(avctx->codec_id) {
+ case CODEC_ID_GSM:
+ avctx->frame_size = GSM_FRAME_SIZE;
+ avctx->block_align = GSM_BLOCK_SIZE;
+ break;
+ case CODEC_ID_GSM_MS: {
+ int one = 1;
+ gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one);
+ avctx->frame_size = 2*GSM_FRAME_SIZE;
+ avctx->block_align = GSM_MS_BLOCK_SIZE;
+ }
+ }
+
avctx->coded_frame= avcodec_alloc_frame();
avctx->coded_frame->key_frame= 1;
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;
+ if(buf_size < avctx->block_align) return 0;
+
+ switch(avctx->codec_id) {
+ case CODEC_ID_GSM:
+ gsm_encode(avctx->priv_data,data,frame);
+ break;
+ case CODEC_ID_GSM_MS:
+ gsm_encode(avctx->priv_data,data,frame);
+ gsm_encode(avctx->priv_data,((short*)data)+GSM_FRAME_SIZE,frame+32);
+ }
+ return avctx->block_align;
}
AVCodec libgsm_encoder = {
- "gsm",
+ "libgsm",
CODEC_TYPE_AUDIO,
CODEC_ID_GSM,
0,
libgsm_close,
};
+AVCodec libgsm_ms_encoder = {
+ "libgsm_ms",
+ CODEC_TYPE_AUDIO,
+ CODEC_ID_GSM_MS,
+ 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;
+ if(buf_size < avctx->block_align) return 0;
+
+ switch(avctx->codec_id) {
+ case CODEC_ID_GSM:
+ if(gsm_decode(avctx->priv_data,buf,data)) return -1;
+ *data_size = GSM_FRAME_SIZE*sizeof(int16_t);
+ break;
+ case CODEC_ID_GSM_MS:
+ if(gsm_decode(avctx->priv_data,buf,data) ||
+ gsm_decode(avctx->priv_data,buf+33,((int16_t*)data)+GSM_FRAME_SIZE)) return -1;
+ *data_size = GSM_FRAME_SIZE*sizeof(int16_t)*2;
+ }
+ return avctx->block_align;
}
AVCodec libgsm_decoder = {
- "gsm",
+ "libgsm",
CODEC_TYPE_AUDIO,
CODEC_ID_GSM,
0,
libgsm_close,
libgsm_decode_frame,
};
+
+AVCodec libgsm_ms_decoder = {
+ "libgsm_ms",
+ CODEC_TYPE_AUDIO,
+ CODEC_ID_GSM_MS,
+ 0,
+ libgsm_init,
+ NULL,
+ libgsm_close,
+ libgsm_decode_frame,
+};