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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 "avcodec.h"

#include "adx.h"

#include "bytestream.h"

#include "internal.h"

#include "put_bits.h"

/**

 * @file

 * 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 void adx_encode(ADXContext *c, uint8_t *adx, const int16_t *wav,

                       ADXChannelState *prev, int channels)

{

    PutBitContext pb;

    int scale;

    int i, j;

    int s0, s1, s2, d;

    int max = 0;

    int min = 0;

    int data[BLOCK_SAMPLES];

    s1 = prev->s1;

    s2 = prev->s2;

    for (i = 0, j = 0; j < 32; i += channels, j++) {

        s0 = wav[i];

        d = ((s0 << COEFF_BITS) - c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS;

        data[j] = d;

        if (max < d)

            max = d;

        if (min > d)

            min = d;

        s2 = s1;

        s1 = s0;

    }

    prev->s1 = s1;

    prev->s2 = s2;

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

        memset(adx, 0, BLOCK_SIZE);

        return;

    }

    if (max / 7 > -min / 8)

        scale = max / 7;

    else

        scale = -min / 8;

    if (scale == 0)

        scale = 1;

    AV_WB16(adx, scale);

    init_put_bits(&pb, adx + 2, 16);

    for (i = 0; i < BLOCK_SAMPLES; i++)

        put_sbits(&pb, 4, av_clip(data[i] / scale, -8, 7));

    flush_put_bits(&pb);

}

#define HEADER_SIZE 36

static int adx_encode_header(AVCodecContext *avctx, uint8_t *buf, int bufsize)

{

    ADXContext *c = avctx->priv_data;

    bytestream_put_be16(&buf, 0x8000);              /* header signature */

    bytestream_put_be16(&buf, HEADER_SIZE - 4);     /* copyright offset */

    bytestream_put_byte(&buf, 3);                   /* encoding */

    bytestream_put_byte(&buf, BLOCK_SIZE);          /* block size */

    bytestream_put_byte(&buf, 4);                   /* sample size */

    bytestream_put_byte(&buf, avctx->channels);     /* channels */

    bytestream_put_be32(&buf, avctx->sample_rate);  /* sample rate */

    bytestream_put_be32(&buf, 0);                   /* total sample count */

    bytestream_put_be16(&buf, c->cutoff);           /* cutoff frequency */

    bytestream_put_byte(&buf, 3);                   /* version */

    bytestream_put_byte(&buf, 0);                   /* flags */

    bytestream_put_be32(&buf, 0);                   /* unknown */

    bytestream_put_be32(&buf, 0);                   /* loop enabled */

    bytestream_put_be16(&buf, 0);                   /* padding */

    bytestream_put_buffer(&buf, "(c)CRI", 6);       /* copyright signature */

    return HEADER_SIZE;

}

static av_cold int adx_encode_init(AVCodecContext *avctx)

{

    ADXContext *c = avctx->priv_data;

    if (avctx->channels > 2) {

        av_log(avctx, AV_LOG_ERROR, "Invalid number of channels\n");

        return AVERROR(EINVAL);

    }

    avctx->frame_size = BLOCK_SAMPLES;

    /* the cutoff can be adjusted, but this seems to work pretty well */

    c->cutoff = 500;

    ff_adx_calculate_coeffs(c->cutoff, avctx->sample_rate, COEFF_BITS, c->coeff);

    return 0;

}

static int adx_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,

                            const AVFrame *frame, int *got_packet_ptr)

{

    ADXContext *c          = avctx->priv_data;

    const int16_t *samples = (const int16_t *)frame->data[0];

    uint8_t *dst;

    int ch, out_size, ret;

    out_size = BLOCK_SIZE * avctx->channels + !c->header_parsed * HEADER_SIZE;

    if ((ret = ff_alloc_packet2(avctx, avpkt, out_size)) < 0)

        return ret;

    dst = avpkt->data;

    if (!c->header_parsed) {

        int hdrsize;

        if ((hdrsize = adx_encode_header(avctx, dst, avpkt->size)) < 0) {

            av_log(avctx, AV_LOG_ERROR, "output buffer is too small\n");

            return AVERROR(EINVAL);

        }

        dst      += hdrsize;

        c->header_parsed = 1;

    }

    for (ch = 0; ch < avctx->channels; ch++) {

        adx_encode(c, dst, samples + ch, &c->prev[ch], avctx->channels);

        dst += BLOCK_SIZE;

    }

    *got_packet_ptr = 1;

    return 0;

}

AVCodec ff_adpcm_adx_encoder = {

    .name           = "adpcm_adx",

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

    .type           = AVMEDIA_TYPE_AUDIO,

    .id             = AV_CODEC_ID_ADPCM_ADX,

    .priv_data_size = sizeof(ADXContext),

    .init           = adx_encode_init,

    .encode2        = adx_encode_frame,

    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16,

                                                      AV_SAMPLE_FMT_NONE },

};