PeerStreamer

/*

 * 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 adx.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/

 */

/* 18 bytes <-> 32 samples */

static void adx_encode(unsigned char *adx,const short *wav,PREV *prev)

{

    int scale;

    int i;

    int s0,s1,s2,d;

    int max=0;

    int min=0;

    int data[32];

    s1 = prev->s1;

    s2 = prev->s2;

    for(i=0;i<32;i++) {

        s0 = wav[i];

        d = ((s0<<14) - SCALE1*s1 + SCALE2*s2)/BASEVOL;

        data[i]=d;

        if (max<d) max=d;

        if (min>d) min=d;

        s2 = s1;

        s1 = s0;

    }

    prev->s1 = s1;

    prev->s2 = s2;

    /* -8..+7 */

    if (max==0 && min==0) {

        memset(adx,0,18);

        return;

    }

    if (max/7>-min/8) scale = max/7;

    else scale = -min/8;

    if (scale==0) scale=1;

    AV_WB16(adx, scale);

    for(i=0;i<16;i++) {

        adx[i+2] = ((data[i*2]/scale)<<4) | ((data[i*2+1]/scale)&0xf);

    }

}

static int adx_encode_header(AVCodecContext *avctx,unsigned char *buf,size_t bufsize)

{

#if 0

    struct {

        uint32_t offset; /* 0x80000000 + sample start - 4 */

        unsigned char unknown1[3]; /* 03 12 04 */

        unsigned char channel; /* 1 or 2 */

        uint32_t freq;

        uint32_t size;

        uint32_t unknown2; /* 01 f4 03 00 */

        uint32_t unknown3; /* 00 00 00 00 */

        uint32_t unknown4; /* 00 00 00 00 */

    /* if loop

        unknown3 00 15 00 01

        unknown4 00 00 00 01

        long loop_start_sample;

        long loop_start_byte;

        long loop_end_sample;

        long loop_end_byte;

        long

    */

    } adxhdr; /* big endian */

    /* offset-6 "(c)CRI" */

#endif

    AV_WB32(buf+0x00,0x80000000|0x20);

    AV_WB32(buf+0x04,0x03120400|avctx->channels);

    AV_WB32(buf+0x08,avctx->sample_rate);

    AV_WB32(buf+0x0c,0); /* FIXME: set after */

    AV_WB32(buf+0x10,0x01040300);

    AV_WB32(buf+0x14,0x00000000);

    AV_WB32(buf+0x18,0x00000000);

    memcpy(buf+0x1c,"\0\0(c)CRI",8);

    return 0x20+4;

}

static av_cold int adx_encode_init(AVCodecContext *avctx)

{

    if (avctx->channels > 2)

        return -1; /* only stereo or mono =) */

    avctx->frame_size = 32;

    avctx->coded_frame= avcodec_alloc_frame();

    avctx->coded_frame->key_frame= 1;

//    avctx->bit_rate = avctx->sample_rate*avctx->channels*18*8/32;

    av_log(avctx, AV_LOG_DEBUG, "adx encode init\n");

    return 0;

}

static av_cold int adx_encode_close(AVCodecContext *avctx)

{

    av_freep(&avctx->coded_frame);

    return 0;

}

static int adx_encode_frame(AVCodecContext *avctx,

                uint8_t *frame, int buf_size, void *data)

{

    ADXContext *c = avctx->priv_data;

    const short *samples = data;

    unsigned char *dst = frame;

    int rest = avctx->frame_size;

/*

    input data size =

    ffmpeg.c: do_audio_out()

    frame_bytes = enc->frame_size * 2 * enc->channels;

*/

//    printf("sz=%d ",buf_size); fflush(stdout);

    if (!c->header_parsed) {

        int hdrsize = adx_encode_header(avctx,dst,buf_size);

        dst+=hdrsize;

        c->header_parsed = 1;

    }

    if (avctx->channels==1) {

        while(rest>=32) {

            adx_encode(dst,samples,c->prev);

            dst+=18;

            samples+=32;

            rest-=32;

        }

    } else {

        while(rest>=32*2) {

            short tmpbuf[32*2];

            int i;

            for(i=0;i<32;i++) {

                tmpbuf[i] = samples[i*2];

                tmpbuf[i+32] = samples[i*2+1];

            }

            adx_encode(dst,tmpbuf,c->prev);

            adx_encode(dst+18,tmpbuf+32,c->prev+1);

            dst+=18*2;

            samples+=32*2;

            rest-=32*2;

        }

    }

    return dst-frame;

}

AVCodec adpcm_adx_encoder = {

    "adpcm_adx",

    CODEC_TYPE_AUDIO,

    CODEC_ID_ADPCM_ADX,

    sizeof(ADXContext),

    adx_encode_init,

    adx_encode_frame,

    adx_encode_close,

    NULL,

    .sample_fmts = (enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},

    .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX"),

};