PeerStreamer

/*

 * 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 "avcodec.h"

#include "truespeech_data.h"

/**

 * @file truespeech.c

 * TrueSpeech decoder.

 */

/**

 * TrueSpeech decoder context

 */

typedef struct {

    /* input data */

    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 int truespeech_decode_init(AVCodecContext * avctx)

{

//    TSContext *c = avctx->priv_data;

    return 0;

}

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

{

    uint32_t t;

    /* first dword */

    t = AV_RL32(input);

    input += 4;

    dec->flag = t & 1;

    dec->vector[0] = ts_codebook[0][(t >>  1) & 0x1F];

    dec->vector[1] = ts_codebook[1][(t >>  6) & 0x1F];

    dec->vector[2] = ts_codebook[2][(t >> 11) &  0xF];

    dec->vector[3] = ts_codebook[3][(t >> 15) &  0xF];

    dec->vector[4] = ts_codebook[4][(t >> 19) &  0xF];

    dec->vector[5] = ts_codebook[5][(t >> 23) &  0x7];

    dec->vector[6] = ts_codebook[6][(t >> 26) &  0x7];

    dec->vector[7] = ts_codebook[7][(t >> 29) &  0x7];

    /* second dword */

    t = AV_RL32(input);

    input += 4;

    dec->offset2[0] = (t >>  0) & 0x7F;

    dec->offset2[1] = (t >>  7) & 0x7F;

    dec->offset2[2] = (t >> 14) & 0x7F;

    dec->offset2[3] = (t >> 21) & 0x7F;

    dec->offset1[0] = ((t >> 28) & 0xF) << 4;

    /* third dword */

    t = AV_RL32(input);

    input += 4;

    dec->pulseval[0] = (t >>  0) & 0x3FFF;

    dec->pulseval[1] = (t >> 14) & 0x3FFF;

    dec->offset1[1] = (t >> 28) & 0x0F;

    /* fourth dword */

    t = AV_RL32(input);

    input += 4;

    dec->pulseval[2] = (t >>  0) & 0x3FFF;

    dec->pulseval[3] = (t >> 14) & 0x3FFF;

    dec->offset1[1] |= ((t >> 28) & 0x0F) << 4;

    /* fifth dword */

    t = AV_RL32(input);

    input += 4;

    dec->pulsepos[0] = (t >> 4) & 0x7FFFFFF;

    dec->pulseoff[0] = (t >> 0) & 0xF;

    dec->offset1[0] |= (t >> 31) & 1;

    /* sixth dword */

    t = AV_RL32(input);

    input += 4;

    dec->pulsepos[1] = (t >> 4) & 0x7FFFFFF;

    dec->pulseoff[1] = (t >> 0) & 0xF;

    dec->offset1[0] |= ((t >> 31) & 1) << 1;

    /* seventh dword */

    t = AV_RL32(input);

    input += 4;

    dec->pulsepos[2] = (t >> 4) & 0x7FFFFFF;

    dec->pulseoff[2] = (t >> 0) & 0xF;

    dec->offset1[0] |= ((t >> 31) & 1) << 2;

    /* eighth dword */

    t = AV_RL32(input);

    input += 4;

    dec->pulsepos[3] = (t >> 4) & 0x7FFFFFF;

    dec->pulseoff[3] = (t >> 0) & 0xF;

    dec->offset1[0] |= ((t >> 31) & 1) << 3;

}

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 * 2);

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

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

                                   (dec->cvector[j] << 15) + 0x4000) >> 15;

        }

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

    }

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

        dec->cvector[i] = (dec->cvector[i] * ts_230[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 * 2);

        return;

    }

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

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

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

    ptr0 = tmp + 145 - off;

    ptr1 = tmp + 146;

    filter = (const int16_t*)ts_240 + (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 * 2);

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

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

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

        tmp[6 - i] = ts_562[dec->pulseoff[quart] * 4 + t];

    }

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

    ptr1 = (const int16_t*)ts_140 + 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 = (const int16_t*)ts_140;

    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;

    for(i = 0; i < 86; i++)

        dec->filtbuf[i] = dec->filtbuf[i + 60];

    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] * ptr1[k];

        sum = (sum + (out[i] << 12) + 0x800) >> 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_5E2[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] = ((out[i] << 12) - sum) >> 12;

    }

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

        t[i] = (ts_5F2[i] * ptr1[i]) >> 15;

    ptr0 = dec->tmp3;

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

        int sum = out[i] << 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,

                void *data, int *data_size,

                uint8_t *buf, int buf_size)

{

    TSContext *c = avctx->priv_data;

    int i;

    short *samples = data;

    int consumed = 0;

    int16_t out_buf[240];

    if (!buf_size)

        return 0;

    while (consumed < buf_size) {

        truespeech_read_frame(c, buf + consumed);

        consumed += 32;

        truespeech_correlate_filter(c);

        truespeech_filters_merge(c);

        memset(out_buf, 0, 240 * 2);

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

            truespeech_apply_twopoint_filter(c, i);

            truespeech_place_pulses(c, out_buf + i * 60, i);

            truespeech_update_filters(c, out_buf + i * 60, i);

            truespeech_synth(c, out_buf + i * 60, i);

        }

        truespeech_save_prevvec(c);

        /* finally output decoded frame */

        for(i = 0; i < 240; i++)

            *samples++ = out_buf[i];

    }

    *data_size = consumed * 15;

    return buf_size;

}

AVCodec truespeech_decoder = {

    "truespeech",

    CODEC_TYPE_AUDIO,

    CODEC_ID_TRUESPEECH,

    sizeof(TSContext),

    truespeech_decode_init,

    NULL,

    NULL,

    truespeech_decode_frame,

};