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ffmpeg / libavcodec / adxenc.c @ 72415b2a

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/*
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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 libavcodec/adxenc.c
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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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/* 18 bytes <-> 32 samples */
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static void adx_encode(unsigned char *adx,const short *wav,PREV *prev)
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{
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    int scale;
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    int i;
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    int s0,s1,s2,d;
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    int max=0;
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    int min=0;
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    int data[32];
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    s1 = prev->s1;
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    s2 = prev->s2;
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    for(i=0;i<32;i++) {
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        s0 = wav[i];
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        d = ((s0<<14) - SCALE1*s1 + SCALE2*s2)/BASEVOL;
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        data[i]=d;
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        if (max<d) max=d;
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        if (min>d) min=d;
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        s2 = s1;
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        s1 = s0;
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    }
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    prev->s1 = s1;
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    prev->s2 = s2;
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    /* -8..+7 */
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    if (max==0 && min==0) {
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        memset(adx,0,18);
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        return;
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    }
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    if (max/7>-min/8) scale = max/7;
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    else scale = -min/8;
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    if (scale==0) scale=1;
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    AV_WB16(adx, scale);
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    for(i=0;i<16;i++) {
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        adx[i+2] = ((data[i*2]/scale)<<4) | ((data[i*2+1]/scale)&0xf);
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    }
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}
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static int adx_encode_header(AVCodecContext *avctx,unsigned char *buf,size_t bufsize)
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{
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#if 0
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    struct {
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        uint32_t offset; /* 0x80000000 + sample start - 4 */
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        unsigned char unknown1[3]; /* 03 12 04 */
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        unsigned char channel; /* 1 or 2 */
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        uint32_t freq;
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        uint32_t size;
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        uint32_t unknown2; /* 01 f4 03 00 */
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        uint32_t unknown3; /* 00 00 00 00 */
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        uint32_t unknown4; /* 00 00 00 00 */
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    /* if loop
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        unknown3 00 15 00 01
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        unknown4 00 00 00 01
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        long loop_start_sample;
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        long loop_start_byte;
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        long loop_end_sample;
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        long loop_end_byte;
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        long
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    */
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    } adxhdr; /* big endian */
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    /* offset-6 "(c)CRI" */
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#endif
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    AV_WB32(buf+0x00,0x80000000|0x20);
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    AV_WB32(buf+0x04,0x03120400|avctx->channels);
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    AV_WB32(buf+0x08,avctx->sample_rate);
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    AV_WB32(buf+0x0c,0); /* FIXME: set after */
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    AV_WB32(buf+0x10,0x01040300);
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    AV_WB32(buf+0x14,0x00000000);
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    AV_WB32(buf+0x18,0x00000000);
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    memcpy(buf+0x1c,"\0\0(c)CRI",8);
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    return 0x20+4;
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}
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static av_cold int adx_encode_init(AVCodecContext *avctx)
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{
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    if (avctx->channels > 2)
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        return -1; /* only stereo or mono =) */
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    avctx->frame_size = 32;
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    avctx->coded_frame= avcodec_alloc_frame();
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    avctx->coded_frame->key_frame= 1;
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//    avctx->bit_rate = avctx->sample_rate*avctx->channels*18*8/32;
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    av_log(avctx, AV_LOG_DEBUG, "adx encode init\n");
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    return 0;
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}
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static av_cold int adx_encode_close(AVCodecContext *avctx)
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{
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    av_freep(&avctx->coded_frame);
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    return 0;
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}
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static int adx_encode_frame(AVCodecContext *avctx,
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                uint8_t *frame, int buf_size, void *data)
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{
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    ADXContext *c = avctx->priv_data;
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    const short *samples = data;
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    unsigned char *dst = frame;
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    int rest = avctx->frame_size;
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/*
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    input data size =
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    ffmpeg.c: do_audio_out()
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    frame_bytes = enc->frame_size * 2 * enc->channels;
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*/
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//    printf("sz=%d ",buf_size); fflush(stdout);
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    if (!c->header_parsed) {
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        int hdrsize = adx_encode_header(avctx,dst,buf_size);
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        dst+=hdrsize;
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        c->header_parsed = 1;
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    }
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    if (avctx->channels==1) {
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        while(rest>=32) {
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            adx_encode(dst,samples,c->prev);
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            dst+=18;
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            samples+=32;
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            rest-=32;
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        }
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    } else {
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        while(rest>=32*2) {
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            short tmpbuf[32*2];
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            int i;
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            for(i=0;i<32;i++) {
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                tmpbuf[i] = samples[i*2];
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                tmpbuf[i+32] = samples[i*2+1];
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            }
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            adx_encode(dst,tmpbuf,c->prev);
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            adx_encode(dst+18,tmpbuf+32,c->prev+1);
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            dst+=18*2;
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            samples+=32*2;
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            rest-=32*2;
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        }
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    }
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    return dst-frame;
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}
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AVCodec adpcm_adx_encoder = {
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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_encode_init,
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    adx_encode_frame,
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    adx_encode_close,
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    NULL,
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    .sample_fmts = (const enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
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    .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
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};