/*

 * DSP Group TrueSpeech compatible decoder

 * Copyright (c) 2005 Konstantin Shishkov

 *

 * 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/mem_internal.h"

#include "avcodec.h"

#include "bswapdsp.h"

#include "codec_internal.h"

#include "decode.h"

#include "get_bits.h"

#include "truespeech_data.h"

/**

 * @file

 * TrueSpeech decoder.

 */

/**

 * TrueSpeech decoder context

 */

typedef struct TSContext {

    BswapDSPContext bdsp;

    /* input data */

    DECLARE_ALIGNED(16, uint8_t, buffer)[32];

    int16_t vector[8];  ///< input vector: 5/5/4/4/4/3/3/3

    int offset1[2];     ///< 8-bit value, used in one copying offset

    int offset2[4];     ///< 7-bit value, encodes offsets for copying and for two-point filter

    int pulseoff[4];    ///< 4-bit offset of pulse values block

    int pulsepos[4];    ///< 27-bit variable, encodes 7 pulse positions

    int pulseval[4];    ///< 7x2-bit pulse values

    int flag;           ///< 1-bit flag, shows how to choose filters

    /* temporary data */

    int filtbuf[146];   // some big vector used for storing filters

    int prevfilt[8];    // filter from previous frame

    int16_t tmp1[8];    // coefficients for adding to out

    int16_t tmp2[8];    // coefficients for adding to out

    int16_t tmp3[8];    // coefficients for adding to out

    int16_t cvector[8]; // correlated input vector

    int filtval;        // gain value for one function

    int16_t newvec[60]; // tmp vector

    int16_t filters[32]; // filters for every subframe

} TSContext;

static av_cold int truespeech_decode_init(AVCodecContext * avctx)

{

    TSContext *c = avctx->priv_data;

    if (avctx->ch_layout.nb_channels != 1) {

        avpriv_request_sample(avctx, "Channel count %d", avctx->ch_layout.nb_channels);

        return AVERROR_PATCHWELCOME;

    }

    av_channel_layout_uninit(&avctx->ch_layout);

    avctx->ch_layout      = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;

    avctx->sample_fmt     = AV_SAMPLE_FMT_S16;

    ff_bswapdsp_init(&c->bdsp);

    return 0;

}

static void truespeech_read_frame(TSContext *dec, const uint8_t *input)

{

    GetBitContext gb;

    dec->bdsp.bswap_buf((uint32_t *) dec->buffer, (const uint32_t *) input, 8);

    init_get_bits(&gb, dec->buffer, 32 * 8);

    dec->vector[7] = ts_codebook[7][get_bits(&gb, 3)];

    dec->vector[6] = ts_codebook[6][get_bits(&gb, 3)];

    dec->vector[5] = ts_codebook[5][get_bits(&gb, 3)];

    dec->vector[4] = ts_codebook[4][get_bits(&gb, 4)];

    dec->vector[3] = ts_codebook[3][get_bits(&gb, 4)];

    dec->vector[2] = ts_codebook[2][get_bits(&gb, 4)];

    dec->vector[1] = ts_codebook[1][get_bits(&gb, 5)];

    dec->vector[0] = ts_codebook[0][get_bits(&gb, 5)];

    dec->flag      = get_bits1(&gb);

    dec->offset1[0] = get_bits(&gb, 4) << 4;

    dec->offset2[3] = get_bits(&gb, 7);

    dec->offset2[2] = get_bits(&gb, 7);

    dec->offset2[1] = get_bits(&gb, 7);

    dec->offset2[0] = get_bits(&gb, 7);

    dec->offset1[1]  = get_bits(&gb, 4);

    dec->pulseval[1] = get_bits(&gb, 14);

    dec->pulseval[0] = get_bits(&gb, 14);

    dec->offset1[1] |= get_bits(&gb, 4) << 4;

    dec->pulseval[3] = get_bits(&gb, 14);

    dec->pulseval[2] = get_bits(&gb, 14);

    dec->offset1[0] |= get_bits1(&gb);

    dec->pulsepos[0] = get_bits_long(&gb, 27);

    dec->pulseoff[0] = get_bits(&gb, 4);

    dec->offset1[0] |= get_bits1(&gb) << 1;

    dec->pulsepos[1] = get_bits_long(&gb, 27);

    dec->pulseoff[1] = get_bits(&gb, 4);

    dec->offset1[0] |= get_bits1(&gb) << 2;

    dec->pulsepos[2] = get_bits_long(&gb, 27);

    dec->pulseoff[2] = get_bits(&gb, 4);

    dec->offset1[0] |= get_bits1(&gb) << 3;

    dec->pulsepos[3] = get_bits_long(&gb, 27);

    dec->pulseoff[3] = get_bits(&gb, 4);

}

static void truespeech_correlate_filter(TSContext *dec)

{

    int16_t tmp[8];

    int i, j;

    for(i = 0; i < 8; i++){

        if(i > 0){

            memcpy(tmp, dec->cvector, i * sizeof(*tmp));

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

                dec->cvector[j] += (tmp[i - j - 1] * dec->vector[i] + 0x4000) >> 15;

        }

        dec->cvector[i] = (8 - dec->vector[i]) >> 3;

    }

    for(i = 0; i < 8; i++)

        dec->cvector[i] = (dec->cvector[i] * ts_decay_994_1000[i]) >> 15;

    dec->filtval = dec->vector[0];

}

static void truespeech_filters_merge(TSContext *dec)

{

    int i;

    if(!dec->flag){

        for(i = 0; i < 8; i++){

            dec->filters[i + 0] = dec->prevfilt[i];

            dec->filters[i + 8] = dec->prevfilt[i];

        }

    }else{

        for(i = 0; i < 8; i++){

            dec->filters[i + 0]=(dec->cvector[i] * 21846 + dec->prevfilt[i] * 10923 + 16384) >> 15;

            dec->filters[i + 8]=(dec->cvector[i] * 10923 + dec->prevfilt[i] * 21846 + 16384) >> 15;

        }

    }

    for(i = 0; i < 8; i++){

        dec->filters[i + 16] = dec->cvector[i];

        dec->filters[i + 24] = dec->cvector[i];

    }

}

static void truespeech_apply_twopoint_filter(TSContext *dec, int quart)

{

    int16_t tmp[146 + 60], *ptr0, *ptr1;

    const int16_t *filter;

    int i, t, off;

    t = dec->offset2[quart];

    if(t == 127){

        memset(dec->newvec, 0, 60 * sizeof(*dec->newvec));

        return;

    }

    for(i = 0; i < 146; i++)

        tmp[i] = dec->filtbuf[i];

    off = (t / 25) + dec->offset1[quart >> 1] + 18;

    off = av_clip(off, 0, 145);

    ptr0 = tmp + 145 - off;

    ptr1 = tmp + 146;

    filter = ts_order2_coeffs + (t % 25) * 2;

    for(i = 0; i < 60; i++){

        t = (ptr0[0] * filter[0] + ptr0[1] * filter[1] + 0x2000) >> 14;

        ptr0++;

        dec->newvec[i] = t;

        ptr1[i] = t;

    }

}

static void truespeech_place_pulses(TSContext *dec, int16_t *out, int quart)

{

    int16_t tmp[7];

    int i, j, t;

    const int16_t *ptr1;

    int16_t *ptr2;

    int coef;

    memset(out, 0, 60 * sizeof(*out));

    for(i = 0; i < 7; i++) {

        t = dec->pulseval[quart] & 3;

        dec->pulseval[quart] >>= 2;

        tmp[6 - i] = ts_pulse_scales[dec->pulseoff[quart] * 4 + t];

    }

    coef = dec->pulsepos[quart] >> 15;

    ptr1 = ts_pulse_values + 30;

    ptr2 = tmp;

    for(i = 0, j = 3; (i < 30) && (j > 0); i++){

        t = *ptr1++;

        if(coef >= t)

            coef -= t;

        else{

            out[i] = *ptr2++;

            ptr1 += 30;

            j--;

        }

    }

    coef = dec->pulsepos[quart] & 0x7FFF;

    ptr1 = ts_pulse_values;

    for(i = 30, j = 4; (i < 60) && (j > 0); i++){

        t = *ptr1++;

        if(coef >= t)

            coef -= t;

        else{

            out[i] = *ptr2++;

            ptr1 += 30;

            j--;

        }

    }

}

static void truespeech_update_filters(TSContext *dec, int16_t *out, int quart)

{

    int i;

    memmove(dec->filtbuf, &dec->filtbuf[60], 86 * sizeof(*dec->filtbuf));

    for(i = 0; i < 60; i++){

        dec->filtbuf[i + 86] = out[i] + dec->newvec[i] - (dec->newvec[i] >> 3);

        out[i] += dec->newvec[i];

    }

}

static void truespeech_synth(TSContext *dec, int16_t *out, int quart)

{

    int i,k;

    int t[8];

    int16_t *ptr0, *ptr1;

    ptr0 = dec->tmp1;

    ptr1 = dec->filters + quart * 8;

    for(i = 0; i < 60; i++){

        int sum = 0;

        for(k = 0; k < 8; k++)

            sum += ptr0[k] * (unsigned)ptr1[k];

        sum = out[i] + ((int)(sum + 0x800U) >> 12);

        out[i] = av_clip(sum, -0x7FFE, 0x7FFE);

        for(k = 7; k > 0; k--)

            ptr0[k] = ptr0[k - 1];

        ptr0[0] = out[i];

    }

    for(i = 0; i < 8; i++)

        t[i] = (ts_decay_35_64[i] * ptr1[i]) >> 15;

    ptr0 = dec->tmp2;

    for(i = 0; i < 60; i++){

        int sum = 0;

        for(k = 0; k < 8; k++)

            sum += ptr0[k] * t[k];

        for(k = 7; k > 0; k--)

            ptr0[k] = ptr0[k - 1];

        ptr0[0] = out[i];

        out[i] += (- sum) >> 12;

    }

    for(i = 0; i < 8; i++)

        t[i] = (ts_decay_3_4[i] * ptr1[i]) >> 15;

    ptr0 = dec->tmp3;

    for(i = 0; i < 60; i++){

        int sum = out[i] * (1 << 12);

        for(k = 0; k < 8; k++)

            sum += ptr0[k] * t[k];

        for(k = 7; k > 0; k--)

            ptr0[k] = ptr0[k - 1];

        ptr0[0] = av_clip((sum + 0x800) >> 12, -0x7FFE, 0x7FFE);

        sum = ((ptr0[1] * (dec->filtval - (dec->filtval >> 2))) >> 4) + sum;

        sum = sum - (sum >> 3);

        out[i] = av_clip((sum + 0x800) >> 12, -0x7FFE, 0x7FFE);

    }

}

static void truespeech_save_prevvec(TSContext *c)

{

    int i;

    for(i = 0; i < 8; i++)

        c->prevfilt[i] = c->cvector[i];

}

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

                                   int *got_frame_ptr, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    TSContext *c = avctx->priv_data;

    int i, j;

    int16_t *samples;

    int iterations, ret;

    iterations = buf_size / 32;

    if (!iterations) {

        av_log(avctx, AV_LOG_ERROR,

               "Too small input buffer (%d bytes), need at least 32 bytes\n", buf_size);

        return -1;

    }

    /* get output buffer */

    frame->nb_samples = iterations * 240;

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

        return ret;

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

    memset(samples, 0, iterations * 240 * sizeof(*samples));

    for(j = 0; j < iterations; j++) {

        truespeech_read_frame(c, buf);

        buf += 32;

        truespeech_correlate_filter(c);

        truespeech_filters_merge(c);

        for(i = 0; i < 4; i++) {

            truespeech_apply_twopoint_filter(c, i);

            truespeech_place_pulses  (c, samples, i);

            truespeech_update_filters(c, samples, i);

            truespeech_synth         (c, samples, i);

            samples += 60;

        }

        truespeech_save_prevvec(c);

    }

    *got_frame_ptr = 1;

    return buf_size;

}

const FFCodec ff_truespeech_decoder = {

    .p.name         = "truespeech",

    CODEC_LONG_NAME("DSP Group TrueSpeech"),

    .p.type         = AVMEDIA_TYPE_AUDIO,

    .p.id           = AV_CODEC_ID_TRUESPEECH,

    .priv_data_size = sizeof(TSContext),

    .init           = truespeech_decode_init,

    FF_CODEC_DECODE_CB(truespeech_decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

};