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/*
* ADX ADPCM codecs
* Copyright (c) 2001,2003 BERO
*
* 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
*/
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "adx.h"
/**
* @file libavcodec/adxdec.c
* SEGA CRI adx codecs.
*
* Reference documents:
* http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
* adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
*/
static av_cold int adx_decode_init(AVCodecContext *avctx)
{
avctx->sample_fmt = SAMPLE_FMT_S16;
return 0;
}
/* 18 bytes <-> 32 samples */
static void adx_decode(short *out,const unsigned char *in,PREV *prev)
{
int scale = AV_RB16(in);
int i;
int s0,s1,s2,d;
// printf("%x ",scale);
in+=2;
s1 = prev->s1;
s2 = prev->s2;
for(i=0;i<16;i++) {
d = in[i];
// d>>=4; if (d&8) d-=16;
d = ((signed char)d >> 4);
s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
s2 = s1;
s1 = av_clip_int16(s0);
*out++=s1;
d = in[i];
//d&=15; if (d&8) d-=16;
d = ((signed char)(d<<4) >> 4);
s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
s2 = s1;
s1 = av_clip_int16(s0);
*out++=s1;
}
prev->s1 = s1;
prev->s2 = s2;
}
static void adx_decode_stereo(short *out,const unsigned char *in,PREV *prev)
{
short tmp[32*2];
int i;
adx_decode(tmp ,in ,prev);
adx_decode(tmp+32,in+18,prev+1);
for(i=0;i<32;i++) {
out[i*2] = tmp[i];
out[i*2+1] = tmp[i+32];
}
}
/* return data offset or 0 */
static int adx_decode_header(AVCodecContext *avctx,const unsigned char *buf,size_t bufsize)
{
int offset;
if (buf[0]!=0x80) return 0;
offset = (AV_RB32(buf)^0x80000000)+4;
if (bufsize<offset || memcmp(buf+offset-6,"(c)CRI",6)) return 0;
avctx->channels = buf[7];
avctx->sample_rate = AV_RB32(buf+8);
avctx->bit_rate = avctx->sample_rate*avctx->channels*18*8/32;
return offset;
}
static int adx_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf0 = avpkt->data;
int buf_size = avpkt->size;
ADXContext *c = avctx->priv_data;
short *samples = data;
const uint8_t *buf = buf0;
int rest = buf_size;
if (!c->header_parsed) {
int hdrsize = adx_decode_header(avctx,buf,rest);
if (hdrsize==0) return -1;
c->header_parsed = 1;
buf += hdrsize;
rest -= hdrsize;
}
/* 18 bytes of data are expanded into 32*2 bytes of audio,
so guard against buffer overflows */
if(rest/18 > *data_size/64)
rest = (*data_size/64) * 18;
if (c->in_temp) {
int copysize = 18*avctx->channels - c->in_temp;
memcpy(c->dec_temp+c->in_temp,buf,copysize);
rest -= copysize;
buf += copysize;
if (avctx->channels==1) {
adx_decode(samples,c->dec_temp,c->prev);
samples += 32;
} else {
adx_decode_stereo(samples,c->dec_temp,c->prev);
samples += 32*2;
}
}
//
if (avctx->channels==1) {
while(rest>=18) {
adx_decode(samples,buf,c->prev);
rest-=18;
buf+=18;
samples+=32;
}
} else {
while(rest>=18*2) {
adx_decode_stereo(samples,buf,c->prev);
rest-=18*2;
buf+=18*2;
samples+=32*2;
}
}
//
c->in_temp = rest;
if (rest) {
memcpy(c->dec_temp,buf,rest);
buf+=rest;
}
*data_size = (uint8_t*)samples - (uint8_t*)data;
// printf("%d:%d ",buf-buf0,*data_size); fflush(stdout);
return buf-buf0;
}
AVCodec adpcm_adx_decoder = {
"adpcm_adx",
AVMEDIA_TYPE_AUDIO,
CODEC_ID_ADPCM_ADX,
sizeof(ADXContext),
adx_decode_init,
NULL,
NULL,
adx_decode_frame,
.long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
};
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