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![Diego Biurrun](/assets/img/avatar_default.png)
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
181 lines
4.6 KiB
C
181 lines
4.6 KiB
C
/*
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* ADX ADPCM codecs
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* Copyright (c) 2001,2003 BERO
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/intreadwrite.h"
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#include "avcodec.h"
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#include "adx.h"
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/**
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* @file
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* SEGA CRI adx codecs.
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*
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* Reference documents:
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* http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
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* adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
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*/
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static av_cold int adx_decode_init(AVCodecContext *avctx)
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{
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avctx->sample_fmt = SAMPLE_FMT_S16;
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return 0;
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}
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/* 18 bytes <-> 32 samples */
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static void adx_decode(short *out,const unsigned char *in,PREV *prev)
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{
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int scale = AV_RB16(in);
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int i;
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int s0,s1,s2,d;
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// printf("%x ",scale);
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in+=2;
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s1 = prev->s1;
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s2 = prev->s2;
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for(i=0;i<16;i++) {
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d = in[i];
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// d>>=4; if (d&8) d-=16;
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d = ((signed char)d >> 4);
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s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
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s2 = s1;
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s1 = av_clip_int16(s0);
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*out++=s1;
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d = in[i];
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//d&=15; if (d&8) d-=16;
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d = ((signed char)(d<<4) >> 4);
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s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
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s2 = s1;
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s1 = av_clip_int16(s0);
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*out++=s1;
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}
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prev->s1 = s1;
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prev->s2 = s2;
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}
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static void adx_decode_stereo(short *out,const unsigned char *in,PREV *prev)
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{
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short tmp[32*2];
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int i;
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adx_decode(tmp ,in ,prev);
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adx_decode(tmp+32,in+18,prev+1);
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for(i=0;i<32;i++) {
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out[i*2] = tmp[i];
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out[i*2+1] = tmp[i+32];
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}
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}
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/* return data offset or 0 */
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static int adx_decode_header(AVCodecContext *avctx,const unsigned char *buf,size_t bufsize)
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{
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int offset;
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if (buf[0]!=0x80) return 0;
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offset = (AV_RB32(buf)^0x80000000)+4;
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if (bufsize<offset || memcmp(buf+offset-6,"(c)CRI",6)) return 0;
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avctx->channels = buf[7];
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avctx->sample_rate = AV_RB32(buf+8);
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avctx->bit_rate = avctx->sample_rate*avctx->channels*18*8/32;
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return offset;
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}
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static int adx_decode_frame(AVCodecContext *avctx,
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void *data, int *data_size,
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AVPacket *avpkt)
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{
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const uint8_t *buf0 = avpkt->data;
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int buf_size = avpkt->size;
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ADXContext *c = avctx->priv_data;
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short *samples = data;
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const uint8_t *buf = buf0;
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int rest = buf_size;
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if (!c->header_parsed) {
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int hdrsize = adx_decode_header(avctx,buf,rest);
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if (hdrsize==0) return -1;
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c->header_parsed = 1;
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buf += hdrsize;
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rest -= hdrsize;
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}
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/* 18 bytes of data are expanded into 32*2 bytes of audio,
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so guard against buffer overflows */
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if(rest/18 > *data_size/64)
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rest = (*data_size/64) * 18;
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if (c->in_temp) {
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int copysize = 18*avctx->channels - c->in_temp;
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memcpy(c->dec_temp+c->in_temp,buf,copysize);
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rest -= copysize;
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buf += copysize;
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if (avctx->channels==1) {
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adx_decode(samples,c->dec_temp,c->prev);
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samples += 32;
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} else {
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adx_decode_stereo(samples,c->dec_temp,c->prev);
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samples += 32*2;
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}
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}
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//
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if (avctx->channels==1) {
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while(rest>=18) {
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adx_decode(samples,buf,c->prev);
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rest-=18;
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buf+=18;
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samples+=32;
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}
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} else {
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while(rest>=18*2) {
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adx_decode_stereo(samples,buf,c->prev);
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rest-=18*2;
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buf+=18*2;
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samples+=32*2;
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}
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}
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//
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c->in_temp = rest;
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if (rest) {
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memcpy(c->dec_temp,buf,rest);
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buf+=rest;
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}
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*data_size = (uint8_t*)samples - (uint8_t*)data;
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// printf("%d:%d ",buf-buf0,*data_size); fflush(stdout);
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return buf-buf0;
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}
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AVCodec adpcm_adx_decoder = {
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"adpcm_adx",
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AVMEDIA_TYPE_AUDIO,
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CODEC_ID_ADPCM_ADX,
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sizeof(ADXContext),
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adx_decode_init,
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NULL,
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NULL,
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adx_decode_frame,
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.long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
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};
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