/*

 * Copyright (c) 2012 Laurent Aimar

 *

 * 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/channel_layout.h"

#include "libavutil/intreadwrite.h"

#include "avcodec.h"

#include "codec_internal.h"

#include "decode.h"

#include "dvaudio.h"

typedef struct DVAudioContext {

    int block_size;

    int is_12bit;

    int is_pal;

    int16_t shuffle[2000];

} DVAudioContext;

static av_cold int decode_init(AVCodecContext *avctx)

{

    DVAudioContext *s = avctx->priv_data;

    int i;

    if (avctx->codec_tag == 0x0215) {

        s->block_size = 7200;

    } else if (avctx->codec_tag == 0x0216) {

        s->block_size = 8640;

    } else if (avctx->block_align == 7200 ||

               avctx->block_align == 8640) {

        s->block_size = avctx->block_align;

    } else {

        return AVERROR(EINVAL);

    }

    s->is_pal = s->block_size == 8640;

    s->is_12bit = avctx->bits_per_coded_sample == 12;

    avctx->sample_fmt = AV_SAMPLE_FMT_S16;

    av_channel_layout_uninit(&avctx->ch_layout);

    avctx->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO;

    for (i = 0; i < FF_ARRAY_ELEMS(s->shuffle); i++) {

        const unsigned a = s->is_pal ? 18 : 15;

        const unsigned b = 3 * a;

        s->shuffle[i] = 80 * ((21 * (i % 3) + 9 * (i / 3) + ((i / a) % 3)) % b) +

                         (2 + s->is_12bit) * (i / b) + 8;

    }

    return 0;

}

static inline uint16_t dv_audio_12to16(uint16_t sample)

{

    uint16_t shift, result;

    sample = (sample < 0x800) ? sample : sample | 0xf000;

    shift  = (sample & 0xf00) >> 8;

    if (shift < 0x2 || shift > 0xd) {

        result = sample;

    } else if (shift < 0x8) {

        shift--;

        result = (sample - (256 * shift)) << shift;

    } else {

        shift  = 0xe - shift;

        result = ((sample + ((256 * shift) + 1)) << shift) - 1;

    }

    return result;

}

static int decode_frame(AVCodecContext *avctx, AVFrame *frame,

                        int *got_frame_ptr, AVPacket *pkt)

{

    DVAudioContext *s = avctx->priv_data;

    const uint8_t *src = pkt->data;

    int16_t *dst;

    int ret, i;

    if (pkt->size < s->block_size)

        return AVERROR_INVALIDDATA;

    frame->nb_samples = dv_get_audio_sample_count(pkt->data + 244, s->is_pal);

    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

        return ret;

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

    for (i = 0; i < frame->nb_samples; i++) {

       const uint8_t *v = &src[s->shuffle[i]];

       if (s->is_12bit) {

           *dst++ = dv_audio_12to16((v[0] << 4) | ((v[2] >> 4) & 0x0f));

           *dst++ = dv_audio_12to16((v[1] << 4) | ((v[2] >> 0) & 0x0f));

       } else {

           *dst++ = AV_RB16(&v[0]);

           *dst++ = AV_RB16(&v[s->is_pal ? 4320 : 3600]);

       }

    }

    *got_frame_ptr = 1;

    return s->block_size;

}

const FFCodec ff_dvaudio_decoder = {

    .p.name         = "dvaudio",

    CODEC_LONG_NAME("Ulead DV Audio"),

    .p.type         = AVMEDIA_TYPE_AUDIO,

    .p.id           = AV_CODEC_ID_DVAUDIO,

    .init           = decode_init,

    FF_CODEC_DECODE_CB(decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

    .priv_data_size = sizeof(DVAudioContext),

};