mirror of
https://github.com/xenia-project/FFmpeg.git
synced 2024-11-25 12:40:01 +00:00
ba87f0801d
Passing an explicit filename to this command is only necessary if the documentation in the @file block refers to a file different from the one the block resides in. Originally committed as revision 22921 to svn://svn.ffmpeg.org/ffmpeg/trunk
114 lines
3.4 KiB
C
114 lines
3.4 KiB
C
/*
|
|
* 8SVX audio decoder
|
|
* Copyright (C) 2008 Jaikrishnan Menon
|
|
*
|
|
* 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
|
|
* 8svx audio decoder
|
|
* @author Jaikrishnan Menon
|
|
* supports: fibonacci delta encoding
|
|
* : exponential encoding
|
|
*/
|
|
|
|
#include "avcodec.h"
|
|
|
|
/** decoder context */
|
|
typedef struct EightSvxContext {
|
|
int16_t fib_acc;
|
|
const int16_t *table;
|
|
} EightSvxContext;
|
|
|
|
static const int16_t fibonacci[16] = { -34<<8, -21<<8, -13<<8, -8<<8, -5<<8, -3<<8, -2<<8, -1<<8,
|
|
0, 1<<8, 2<<8, 3<<8, 5<<8, 8<<8, 13<<8, 21<<8 };
|
|
static const int16_t exponential[16] = { -128<<8, -64<<8, -32<<8, -16<<8, -8<<8, -4<<8, -2<<8, -1<<8,
|
|
0, 1<<8, 2<<8, 4<<8, 8<<8, 16<<8, 32<<8, 64<<8 };
|
|
|
|
/** decode a frame */
|
|
static int eightsvx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
|
|
AVPacket *avpkt)
|
|
{
|
|
const uint8_t *buf = avpkt->data;
|
|
int buf_size = avpkt->size;
|
|
EightSvxContext *esc = avctx->priv_data;
|
|
int16_t *out_data = data;
|
|
int consumed = buf_size;
|
|
const uint8_t *buf_end = buf + buf_size;
|
|
|
|
if((*data_size >> 2) < buf_size)
|
|
return -1;
|
|
|
|
if(avctx->frame_number == 0) {
|
|
esc->fib_acc = buf[1] << 8;
|
|
buf_size -= 2;
|
|
buf += 2;
|
|
}
|
|
|
|
*data_size = buf_size << 2;
|
|
|
|
while(buf < buf_end) {
|
|
uint8_t d = *buf++;
|
|
esc->fib_acc += esc->table[d & 0x0f];
|
|
*out_data++ = esc->fib_acc;
|
|
esc->fib_acc += esc->table[d >> 4];
|
|
*out_data++ = esc->fib_acc;
|
|
}
|
|
|
|
return consumed;
|
|
}
|
|
|
|
/** initialize 8svx decoder */
|
|
static av_cold int eightsvx_decode_init(AVCodecContext *avctx)
|
|
{
|
|
EightSvxContext *esc = avctx->priv_data;
|
|
|
|
switch(avctx->codec->id) {
|
|
case CODEC_ID_8SVX_FIB:
|
|
esc->table = fibonacci;
|
|
break;
|
|
case CODEC_ID_8SVX_EXP:
|
|
esc->table = exponential;
|
|
break;
|
|
default:
|
|
return -1;
|
|
}
|
|
avctx->sample_fmt = SAMPLE_FMT_S16;
|
|
return 0;
|
|
}
|
|
|
|
AVCodec eightsvx_fib_decoder = {
|
|
.name = "8svx_fib",
|
|
.type = AVMEDIA_TYPE_AUDIO,
|
|
.id = CODEC_ID_8SVX_FIB,
|
|
.priv_data_size = sizeof (EightSvxContext),
|
|
.init = eightsvx_decode_init,
|
|
.decode = eightsvx_decode_frame,
|
|
.long_name = NULL_IF_CONFIG_SMALL("8SVX fibonacci"),
|
|
};
|
|
|
|
AVCodec eightsvx_exp_decoder = {
|
|
.name = "8svx_exp",
|
|
.type = AVMEDIA_TYPE_AUDIO,
|
|
.id = CODEC_ID_8SVX_EXP,
|
|
.priv_data_size = sizeof (EightSvxContext),
|
|
.init = eightsvx_decode_init,
|
|
.decode = eightsvx_decode_frame,
|
|
.long_name = NULL_IF_CONFIG_SMALL("8SVX exponential"),
|
|
};
|