PeerStreamer

/*

 * TwinVQ decoder

 * Copyright (c) 2009 Vitor Sessak

 *

 * 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 "get_bits.h"

#include "dsputil.h"

#include "fft.h"

#include "lsp.h"

#include <math.h>

#include <stdint.h>

#include "twinvq_data.h"

enum FrameType {

    FT_SHORT = 0,  ///< Short frame  (divided in n   sub-blocks)

    FT_MEDIUM,     ///< Medium frame (divided in m<n sub-blocks)

    FT_LONG,       ///< Long frame   (single sub-block + PPC)

    FT_PPC,        ///< Periodic Peak Component (part of the long frame)

};

/**

 * Parameters and tables that are different for each frame type

 */

struct FrameMode {

    uint8_t         sub;      ///< Number subblocks in each frame

    const uint16_t *bark_tab;

    /** number of distinct bark scale envelope values */

    uint8_t         bark_env_size;

    const int16_t  *bark_cb;    ///< codebook for the bark scale envelope (BSE)

    uint8_t         bark_n_coef;///< number of BSE CB coefficients to read

    uint8_t         bark_n_bit; ///< number of bits of the BSE coefs

    //@{

    /** main codebooks for spectrum data */

    const int16_t    *cb0;

    const int16_t    *cb1;

    //@}

    uint8_t         cb_len_read; ///< number of spectrum coefficients to read

};

/**

 * Parameters and tables that are different for every combination of

 * bitrate/sample rate

 */

typedef struct {

    struct FrameMode fmode[3]; ///< frame type-dependant parameters

    uint16_t     size;        ///< frame size in samples

    uint8_t      n_lsp;       ///< number of lsp coefficients

    const float *lspcodebook;

    /* number of bits of the different LSP CB coefficients */

    uint8_t      lsp_bit0;

    uint8_t      lsp_bit1;

    uint8_t      lsp_bit2;

    uint8_t      lsp_split;      ///< number of CB entries for the LSP decoding

    const int16_t *ppc_shape_cb; ///< PPC shape CB

    /** number of the bits for the PPC period value */

    uint8_t      ppc_period_bit;

    uint8_t      ppc_shape_bit;  ///< number of bits of the PPC shape CB coeffs

    uint8_t      ppc_shape_len;  ///< size of PPC shape CB

    uint8_t      pgain_bit;      ///< bits for PPC gain

    /** constant for peak period to peak width conversion */

    uint16_t     peak_per2wid;

} ModeTab;

static const ModeTab mode_08_08 = {

    {

        { 8, bark_tab_s08_64,  10, tab.fcb08s  , 1, 5, tab.cb0808s0, tab.cb0808s1, 18},

        { 2, bark_tab_m08_256, 20, tab.fcb08m  , 2, 5, tab.cb0808m0, tab.cb0808m1, 16},

        { 1, bark_tab_l08_512, 30, tab.fcb08l  , 3, 6, tab.cb0808l0, tab.cb0808l1, 17}

    },

    512 , 12, tab.lsp08,   1, 5, 3, 3, tab.shape08  , 8, 28, 20, 6, 40

};

static const ModeTab mode_11_08 = {

    {

        { 8, bark_tab_s11_64,  10, tab.fcb11s  , 1, 5, tab.cb1108s0, tab.cb1108s1, 29},

        { 2, bark_tab_m11_256, 20, tab.fcb11m  , 2, 5, tab.cb1108m0, tab.cb1108m1, 24},

        { 1, bark_tab_l11_512, 30, tab.fcb11l  , 3, 6, tab.cb1108l0, tab.cb1108l1, 27}

    },

    512 , 16, tab.lsp11,   1, 6, 4, 3, tab.shape11  , 9, 36, 30, 7, 90

};

static const ModeTab mode_11_10 = {

    {

        { 8, bark_tab_s11_64,  10, tab.fcb11s  , 1, 5, tab.cb1110s0, tab.cb1110s1, 21},

        { 2, bark_tab_m11_256, 20, tab.fcb11m  , 2, 5, tab.cb1110m0, tab.cb1110m1, 18},

        { 1, bark_tab_l11_512, 30, tab.fcb11l  , 3, 6, tab.cb1110l0, tab.cb1110l1, 20}

    },

    512 , 16, tab.lsp11,   1, 6, 4, 3, tab.shape11  , 9, 36, 30, 7, 90

};

static const ModeTab mode_16_16 = {

    {

        { 8, bark_tab_s16_128, 10, tab.fcb16s  , 1, 5, tab.cb1616s0, tab.cb1616s1, 16},

        { 2, bark_tab_m16_512, 20, tab.fcb16m  , 2, 5, tab.cb1616m0, tab.cb1616m1, 15},

        { 1, bark_tab_l16_1024,30, tab.fcb16l  , 3, 6, tab.cb1616l0, tab.cb1616l1, 16}

    },

    1024, 16, tab.lsp16,   1, 6, 4, 3, tab.shape16  , 9, 56, 60, 7, 180

};

static const ModeTab mode_22_20 = {

    {

        { 8, bark_tab_s22_128, 10, tab.fcb22s_1, 1, 6, tab.cb2220s0, tab.cb2220s1, 18},

        { 2, bark_tab_m22_512, 20, tab.fcb22m_1, 2, 6, tab.cb2220m0, tab.cb2220m1, 17},

        { 1, bark_tab_l22_1024,32, tab.fcb22l_1, 4, 6, tab.cb2220l0, tab.cb2220l1, 18}

    },

    1024, 16, tab.lsp22_1, 1, 6, 4, 3, tab.shape22_1, 9, 56, 36, 7, 144

};

static const ModeTab mode_22_24 = {

    {

        { 8, bark_tab_s22_128, 10, tab.fcb22s_1, 1, 6, tab.cb2224s0, tab.cb2224s1, 15},

        { 2, bark_tab_m22_512, 20, tab.fcb22m_1, 2, 6, tab.cb2224m0, tab.cb2224m1, 14},

        { 1, bark_tab_l22_1024,32, tab.fcb22l_1, 4, 6, tab.cb2224l0, tab.cb2224l1, 15}

    },

    1024, 16, tab.lsp22_1, 1, 6, 4, 3, tab.shape22_1, 9, 56, 36, 7, 144

};

static const ModeTab mode_22_32 = {

    {

        { 4, bark_tab_s22_128, 10, tab.fcb22s_2, 1, 6, tab.cb2232s0, tab.cb2232s1, 11},

        { 2, bark_tab_m22_256, 20, tab.fcb22m_2, 2, 6, tab.cb2232m0, tab.cb2232m1, 11},

        { 1, bark_tab_l22_512, 32, tab.fcb22l_2, 4, 6, tab.cb2232l0, tab.cb2232l1, 12}

    },

    512 , 16, tab.lsp22_2, 1, 6, 4, 4, tab.shape22_2, 9, 56, 36, 7, 72

};

static const ModeTab mode_44_40 = {

    {

        {16, bark_tab_s44_128, 10, tab.fcb44s  , 1, 6, tab.cb4440s0, tab.cb4440s1, 18},

        { 4, bark_tab_m44_512, 20, tab.fcb44m  , 2, 6, tab.cb4440m0, tab.cb4440m1, 17},

        { 1, bark_tab_l44_2048,40, tab.fcb44l  , 4, 6, tab.cb4440l0, tab.cb4440l1, 17}

    },

    2048, 20, tab.lsp44,   1, 6, 4, 4, tab.shape44  , 9, 84, 54, 7, 432

};

static const ModeTab mode_44_48 = {

    {

        {16, bark_tab_s44_128, 10, tab.fcb44s  , 1, 6, tab.cb4448s0, tab.cb4448s1, 15},

        { 4, bark_tab_m44_512, 20, tab.fcb44m  , 2, 6, tab.cb4448m0, tab.cb4448m1, 14},

        { 1, bark_tab_l44_2048,40, tab.fcb44l  , 4, 6, tab.cb4448l0, tab.cb4448l1, 14}

    },

    2048, 20, tab.lsp44,   1, 6, 4, 4, tab.shape44  , 9, 84, 54, 7, 432

};

typedef struct TwinContext {

    AVCodecContext *avctx;

    DSPContext      dsp;

    FFTContext mdct_ctx[3];

    const ModeTab *mtab;

    // history

    float lsp_hist[2][20];           ///< LSP coefficients of the last frame

    float bark_hist[3][2][40];       ///< BSE coefficients of last frame

    // bitstream parameters

    int16_t permut[4][4096];

    uint8_t length[4][2];            ///< main codebook stride

    uint8_t length_change[4];

    uint8_t bits_main_spec[2][4][2]; ///< bits for the main codebook

    int bits_main_spec_change[4];

    int n_div[4];

    float *spectrum;

    float *curr_frame;               ///< non-interleaved output

    float *prev_frame;               ///< non-interleaved previous frame

    int last_block_pos[2];

    float *cos_tabs[3];

    // scratch buffers

    float *tmp_buf;

} TwinContext;

#define PPC_SHAPE_CB_SIZE 64

#define PPC_SHAPE_LEN_MAX 60

#define SUB_AMP_MAX       4500.0

#define MULAW_MU          100.0

#define GAIN_BITS         8

#define AMP_MAX           13000.0

#define SUB_GAIN_BITS     5

#define WINDOW_TYPE_BITS  4

#define PGAIN_MU          200

#define LSP_COEFS_MAX     20

#define LSP_SPLIT_MAX     4

#define CHANNELS_MAX      2

#define SUBBLOCKS_MAX     16

#define BARK_N_COEF_MAX   4

/** @note not speed critical, hence not optimized */

static void memset_float(float *buf, float val, int size)

{

    while (size--)

        *buf++ = val;

}

/**

 * Evaluate a single LPC amplitude spectrum envelope coefficient from the line

 * spectrum pairs.

 *

 * @param lsp a vector of the cosinus of the LSP values

 * @param cos_val cos(PI*i/N) where i is the index of the LPC amplitude

 * @param order the order of the LSP (and the size of the *lsp buffer). Must

 *        be a multiple of four.

 * @return the LPC value

 *

 * @todo reuse code from vorbis_dec.c: vorbis_floor0_decode

 */

static float eval_lpc_spectrum(const float *lsp, float cos_val, int order)

{

    int j;

    float p = 0.5f;

    float q = 0.5f;

    float two_cos_w = 2.0f*cos_val;

    for (j = 0; j + 1 < order; j += 2*2) {

        // Unroll the loop once since order is a multiple of four

        q *= lsp[j  ] - two_cos_w;

        p *= lsp[j+1] - two_cos_w;

        q *= lsp[j+2] - two_cos_w;

        p *= lsp[j+3] - two_cos_w;

    }

    p *= p * (2.0f - two_cos_w);

    q *= q * (2.0f + two_cos_w);

    return 0.5 / (p + q);

}

/**

 * Evaluate the LPC amplitude spectrum envelope from the line spectrum pairs.

 */

static void eval_lpcenv(TwinContext *tctx, const float *cos_vals, float *lpc)

{

    int i;

    const ModeTab *mtab = tctx->mtab;

    int size_s = mtab->size / mtab->fmode[FT_SHORT].sub;

    for (i = 0; i < size_s/2; i++) {

        float cos_i = tctx->cos_tabs[0][i];

        lpc[i]          = eval_lpc_spectrum(cos_vals,  cos_i, mtab->n_lsp);

        lpc[size_s-i-1] = eval_lpc_spectrum(cos_vals, -cos_i, mtab->n_lsp);

    }

}

static void interpolate(float *out, float v1, float v2, int size)

{

    int i;

    float step = (v1 - v2)/(size + 1);

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

        v2 += step;

        out[i] = v2;

    }

}

static inline float get_cos(int idx, int part, const float *cos_tab, int size)

{

    return part ? -cos_tab[size - idx - 1] :

                   cos_tab[       idx    ];

}

/**

 * Evaluate the LPC amplitude spectrum envelope from the line spectrum pairs.

 * Probably for speed reasons, the coefficients are evaluated as

 * siiiibiiiisiiiibiiiisiiiibiiiisiiiibiiiis ...

 * where s is an evaluated value, i is a value interpolated from the others

 * and b might be either calculated or interpolated, depending on an

 * unexplained condition.

 *

 * @param step the size of a block "siiiibiiii"

 * @param in the cosinus of the LSP data

 * @param part is 0 for 0...PI (positive cossinus values) and 1 for PI...2PI

          (negative cossinus values)

 * @param size the size of the whole output

 */

static inline void eval_lpcenv_or_interp(TwinContext *tctx,

                                         enum FrameType ftype,

                                         float *out, const float *in,

                                         int size, int step, int part)

{

    int i;

    const ModeTab *mtab = tctx->mtab;

    const float *cos_tab = tctx->cos_tabs[ftype];

    // Fill the 's'

    for (i = 0; i < size; i += step)

        out[i] =

            eval_lpc_spectrum(in,

                              get_cos(i, part, cos_tab, size),

                              mtab->n_lsp);

    // Fill the 'iiiibiiii'

    for (i = step; i <= size - 2*step; i += step) {

        if (out[i + step] + out[i - step] >  1.95*out[i] ||

            out[i + step]                 >=  out[i - step]) {

            interpolate(out + i - step + 1, out[i], out[i-step], step - 1);

        } else {

            out[i - step/2] =

                eval_lpc_spectrum(in,

                                  get_cos(i-step/2, part, cos_tab, size),

                                  mtab->n_lsp);

            interpolate(out + i - step   + 1, out[i-step/2], out[i-step  ], step/2 - 1);

            interpolate(out + i - step/2 + 1, out[i       ], out[i-step/2], step/2 - 1);

        }

    }

    interpolate(out + size - 2*step + 1, out[size-step], out[size - 2*step], step - 1);

}

static void eval_lpcenv_2parts(TwinContext *tctx, enum FrameType ftype,

                               const float *buf, float *lpc,

                               int size, int step)

{

    eval_lpcenv_or_interp(tctx, ftype, lpc         , buf, size/2,   step, 0);

    eval_lpcenv_or_interp(tctx, ftype, lpc + size/2, buf, size/2, 2*step, 1);

    interpolate(lpc+size/2-step+1, lpc[size/2], lpc[size/2-step], step);

    memset_float(lpc + size - 2*step + 1, lpc[size - 2*step], 2*step - 1);

}

/**

 * Inverse quantization. Read CB coefficients for cb1 and cb2 from the

 * bitstream, sum the corresponding vectors and write the result to *out

 * after permutation.

 */

static void dequant(TwinContext *tctx, GetBitContext *gb, float *out,

                    enum FrameType ftype,

                    const int16_t *cb0, const int16_t *cb1, int cb_len)

{

    int pos = 0;

    int i, j;

    for (i = 0; i < tctx->n_div[ftype]; i++) {

        int tmp0, tmp1;

        int sign0 = 1;

        int sign1 = 1;

        const int16_t *tab0, *tab1;

        int length = tctx->length[ftype][i >= tctx->length_change[ftype]];

        int bitstream_second_part = (i >= tctx->bits_main_spec_change[ftype]);

        int bits = tctx->bits_main_spec[0][ftype][bitstream_second_part];

        if (bits == 7) {

            if (get_bits1(gb))

                sign0 = -1;

            bits = 6;

        }

        tmp0 = get_bits(gb, bits);

        bits = tctx->bits_main_spec[1][ftype][bitstream_second_part];

        if (bits == 7) {

            if (get_bits1(gb))

                sign1 = -1;

            bits = 6;

        }

        tmp1 = get_bits(gb, bits);

        tab0 = cb0 + tmp0*cb_len;

        tab1 = cb1 + tmp1*cb_len;

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

            out[tctx->permut[ftype][pos+j]] = sign0*tab0[j] + sign1*tab1[j];

        pos += length;

    }

}

static inline float mulawinv(float y, float clip, float mu)

{

    y = av_clipf(y/clip, -1, 1);

    return clip * FFSIGN(y) * (exp(log(1+mu) * fabs(y)) - 1) / mu;

}

/**

 * Evaluate a*b/400 rounded to the nearest integer. When, for example,

 * a*b == 200 and the nearest integer is ill-defined, use a table to emulate

 * the following broken float-based implementation used by the binary decoder:

 *

 * \code

 * static int very_broken_op(int a, int b)

 * {

 *    static float test; // Ugh, force gcc to do the division first...

 *

 *    test = a/400.;

 *    return b * test +  0.5;

 * }

 * \endcode

 *

 * @note if this function is replaced by just ROUNDED_DIV(a*b,400.), the stddev

 * between the original file (before encoding with Yamaha encoder) and the

 * decoded output increases, which leads one to believe that the encoder expects

 * exactly this broken calculation.

 */

static int very_broken_op(int a, int b)

{

    int x = a*b + 200;

    int size;

    const uint8_t *rtab;

    if (x%400 || b%5)

        return x/400;

    x /= 400;

    size = tabs[b/5].size;

    rtab = tabs[b/5].tab;

    return x - rtab[size*av_log2(2*(x - 1)/size)+(x - 1)%size];

}

/**

 * Sum to data a periodic peak of a given period, width and shape.

 *

 * @param period the period of the peak divised by 400.0

 */

static void add_peak(int period, int width, const float *shape,

                     float ppc_gain, float *speech, int len)

{

    int i, j;

    const float *shape_end = shape + len;

    int center;

    // First peak centered around zero

    for (i = 0; i < width/2; i++)

        speech[i] += ppc_gain * *shape++;

    for (i = 1; i < ROUNDED_DIV(len,width) ; i++) {

        center = very_broken_op(period, i);

        for (j = -width/2; j < (width+1)/2; j++)

            speech[j+center] += ppc_gain * *shape++;

    }

    // For the last block, be careful not to go beyond the end of the buffer

    center = very_broken_op(period, i);

    for (j = -width/2; j < (width + 1)/2 && shape < shape_end; j++)

        speech[j+center] += ppc_gain * *shape++;

}

static void decode_ppc(TwinContext *tctx, int period_coef, const float *shape,

                       float ppc_gain, float *speech)

{

    const ModeTab *mtab = tctx->mtab;

    int isampf = tctx->avctx->sample_rate/1000;

    int ibps = tctx->avctx->bit_rate/(1000 * tctx->avctx->channels);

    int min_period = ROUNDED_DIV(  40*2*mtab->size, isampf);

    int max_period = ROUNDED_DIV(6*40*2*mtab->size, isampf);

    int period_range = max_period - min_period;

    // This is actually the period multiplied by 400. It is just linearly coded

    // between its maximum and minimum value.

    int period = min_period +

        ROUNDED_DIV(period_coef*period_range, (1 << mtab->ppc_period_bit) - 1);

    int width;

    if (isampf == 22 && ibps == 32) {

        // For some unknown reason, NTT decided to code this case differently...

        width = ROUNDED_DIV((period + 800)* mtab->peak_per2wid, 400*mtab->size);

    } else

        width =             (period      )* mtab->peak_per2wid/(400*mtab->size);

    add_peak(period, width, shape, ppc_gain, speech, mtab->ppc_shape_len);

}

static void dec_gain(TwinContext *tctx, GetBitContext *gb, enum FrameType ftype,

                     float *out)

{

    const ModeTab *mtab = tctx->mtab;

    int i, j;

    int sub = mtab->fmode[ftype].sub;

    float step     = AMP_MAX     / ((1 <<     GAIN_BITS) - 1);

    float sub_step = SUB_AMP_MAX / ((1 << SUB_GAIN_BITS) - 1);

    if (ftype == FT_LONG) {

        for (i = 0; i < tctx->avctx->channels; i++)

            out[i] = (1./(1<<13)) *

                mulawinv(step * 0.5 + step * get_bits(gb, GAIN_BITS),

                         AMP_MAX, MULAW_MU);

    } else {

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

            float val = (1./(1<<23)) *

                mulawinv(step * 0.5 + step * get_bits(gb, GAIN_BITS),

                         AMP_MAX, MULAW_MU);

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

                out[i*sub + j] =

                    val*mulawinv(sub_step* 0.5 +

                                 sub_step* get_bits(gb, SUB_GAIN_BITS),

                                 SUB_AMP_MAX, MULAW_MU);

            }

        }

    }

}

/**

 * Rearrange the LSP coefficients so that they have a minimum distance of

 * min_dist. This function does it exactly as described in section of 3.2.4

 * of the G.729 specification (but interestingly is different from what the

 * reference decoder actually does).

 */

static void rearrange_lsp(int order, float *lsp, float min_dist)

{

    int i;

    float min_dist2 = min_dist * 0.5;

    for (i = 1; i < order; i++)

        if (lsp[i] - lsp[i-1] < min_dist) {

            float avg = (lsp[i] + lsp[i-1]) * 0.5;

            lsp[i-1] = avg - min_dist2;

            lsp[i  ] = avg + min_dist2;

        }

}

static void decode_lsp(TwinContext *tctx, int lpc_idx1, uint8_t *lpc_idx2,

                       int lpc_hist_idx, float *lsp, float *hist)

{

    const ModeTab *mtab = tctx->mtab;

    int i, j;

    const float *cb  =  mtab->lspcodebook;

    const float *cb2 =  cb  + (1 << mtab->lsp_bit1)*mtab->n_lsp;

    const float *cb3 =  cb2 + (1 << mtab->lsp_bit2)*mtab->n_lsp;

    const int8_t funny_rounding[4] = {

        -2,

        mtab->lsp_split == 4 ? -2 : 1,

        mtab->lsp_split == 4 ? -2 : 1,

        0

    };

    j = 0;

    for (i = 0; i < mtab->lsp_split; i++) {

        int chunk_end = ((i + 1)*mtab->n_lsp + funny_rounding[i])/mtab->lsp_split;

        for (; j < chunk_end; j++)

            lsp[j] = cb [lpc_idx1    * mtab->n_lsp + j] +

                     cb2[lpc_idx2[i] * mtab->n_lsp + j];

    }

    rearrange_lsp(mtab->n_lsp, lsp, 0.0001);

    for (i = 0; i < mtab->n_lsp; i++) {

        float tmp1 = 1. -          cb3[lpc_hist_idx*mtab->n_lsp + i];

        float tmp2 =     hist[i] * cb3[lpc_hist_idx*mtab->n_lsp + i];

        hist[i] = lsp[i];

        lsp[i]  = lsp[i] * tmp1 + tmp2;

    }

    rearrange_lsp(mtab->n_lsp, lsp, 0.0001);

    rearrange_lsp(mtab->n_lsp, lsp, 0.000095);

    ff_sort_nearly_sorted_floats(lsp, mtab->n_lsp);

}

static void dec_lpc_spectrum_inv(TwinContext *tctx, float *lsp,

                                 enum FrameType ftype, float *lpc)

{

    int i;

    int size = tctx->mtab->size / tctx->mtab->fmode[ftype].sub;

    for (i = 0; i < tctx->mtab->n_lsp; i++)

        lsp[i] =  2*cos(lsp[i]);

    switch (ftype) {

    case FT_LONG:

        eval_lpcenv_2parts(tctx, ftype, lsp, lpc, size, 8);

        break;

    case FT_MEDIUM:

        eval_lpcenv_2parts(tctx, ftype, lsp, lpc, size, 2);

        break;

    case FT_SHORT:

        eval_lpcenv(tctx, lsp, lpc);

        break;

    }

}

static void imdct_and_window(TwinContext *tctx, enum FrameType ftype, int wtype,

                            float *in, float *prev, int ch)

{

    const ModeTab *mtab = tctx->mtab;

    int bsize = mtab->size / mtab->fmode[ftype].sub;

    int size  = mtab->size;

    float *buf1 = tctx->tmp_buf;

    int j;

    int wsize; // Window size

    float *out = tctx->curr_frame + 2*ch*mtab->size;

    float *out2 = out;

    float *prev_buf;

    int first_wsize;

    static const uint8_t wtype_to_wsize[]      = {0, 0, 2, 2, 2, 1, 0, 1, 1};

    int types_sizes[] = {

        mtab->size /    mtab->fmode[FT_LONG  ].sub,

        mtab->size /    mtab->fmode[FT_MEDIUM].sub,

        mtab->size / (2*mtab->fmode[FT_SHORT ].sub),

    };

    wsize = types_sizes[wtype_to_wsize[wtype]];

    first_wsize = wsize;

    prev_buf = prev + (size - bsize)/2;

    for (j = 0; j < mtab->fmode[ftype].sub; j++) {

        int sub_wtype = ftype == FT_MEDIUM ? 8 : wtype;

        if (!j && wtype == 4)

            sub_wtype = 4;

        else if (j == mtab->fmode[ftype].sub-1 && wtype == 7)

            sub_wtype = 7;

        wsize = types_sizes[wtype_to_wsize[sub_wtype]];

        ff_imdct_half(&tctx->mdct_ctx[ftype], buf1 + bsize*j, in + bsize*j);

        tctx->dsp.vector_fmul_window(out2,

                                     prev_buf + (bsize-wsize)/2,

                                     buf1 + bsize*j,

                                     ff_sine_windows[av_log2(wsize)],

                                     0.0,

                                     wsize/2);

        out2 += wsize;

        memcpy(out2, buf1 + bsize*j + wsize/2, (bsize - wsize/2)*sizeof(float));

        out2 += ftype == FT_MEDIUM ? (bsize-wsize)/2 : bsize - wsize;

        prev_buf = buf1 + bsize*j + bsize/2;

    }

    tctx->last_block_pos[ch] = (size + first_wsize)/2;

}

static void imdct_output(TwinContext *tctx, enum FrameType ftype, int wtype,

                         float *out)

{

    const ModeTab *mtab = tctx->mtab;

    float *prev_buf = tctx->prev_frame + tctx->last_block_pos[0];

    int i, j;

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

        imdct_and_window(tctx, ftype, wtype,

                         tctx->spectrum + i*mtab->size,

                         prev_buf + 2*i*mtab->size,

                         i);

    }

    if (tctx->avctx->channels == 2) {

        for (i = 0; i < mtab->size - tctx->last_block_pos[0]; i++) {

            float f1 = prev_buf[               i];

            float f2 = prev_buf[2*mtab->size + i];

            out[2*i    ] = f1 + f2;

            out[2*i + 1] = f1 - f2;

        }

        for (j = 0; i < mtab->size; j++,i++) {

            float f1 = tctx->curr_frame[               j];

            float f2 = tctx->curr_frame[2*mtab->size + j];

            out[2*i    ] = f1 + f2;

            out[2*i + 1] = f1 - f2;

        }

    } else {

        memcpy(out, prev_buf,

               (mtab->size - tctx->last_block_pos[0]) * sizeof(*out));

        out +=  mtab->size - tctx->last_block_pos[0];

        memcpy(out, tctx->curr_frame,

               (tctx->last_block_pos[0]) * sizeof(*out));

    }

}

static void dec_bark_env(TwinContext *tctx, const uint8_t *in, int use_hist,

                         int ch, float *out, float gain, enum FrameType ftype)

{

    const ModeTab *mtab = tctx->mtab;

    int i,j;

    float *hist = tctx->bark_hist[ftype][ch];

    float val = ((const float []) {0.4, 0.35, 0.28})[ftype];

    int bark_n_coef  = mtab->fmode[ftype].bark_n_coef;

    int fw_cb_len = mtab->fmode[ftype].bark_env_size / bark_n_coef;

    int idx = 0;

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

        for (j = 0; j < bark_n_coef; j++, idx++) {

            float tmp2 =

                mtab->fmode[ftype].bark_cb[fw_cb_len*in[j] + i] * (1./4096);

            float st = use_hist ?

                (1. - val) * tmp2 + val*hist[idx] + 1. : tmp2 + 1.;

            hist[idx] = tmp2;

            if (st < -1.) st = 1.;

            memset_float(out, st * gain, mtab->fmode[ftype].bark_tab[idx]);

            out += mtab->fmode[ftype].bark_tab[idx];

        }

}

static void read_and_decode_spectrum(TwinContext *tctx, GetBitContext *gb,

                                     float *out, enum FrameType ftype)

{

    const ModeTab *mtab = tctx->mtab;

    int channels = tctx->avctx->channels;

    int sub = mtab->fmode[ftype].sub;

    int block_size = mtab->size / sub;

    float gain[CHANNELS_MAX*SUBBLOCKS_MAX];

    float ppc_shape[PPC_SHAPE_LEN_MAX * CHANNELS_MAX * 4];

    uint8_t bark1[CHANNELS_MAX][SUBBLOCKS_MAX][BARK_N_COEF_MAX];

    uint8_t bark_use_hist[CHANNELS_MAX][SUBBLOCKS_MAX];

    uint8_t lpc_idx1[CHANNELS_MAX];

    uint8_t lpc_idx2[CHANNELS_MAX][LSP_SPLIT_MAX];

    uint8_t lpc_hist_idx[CHANNELS_MAX];

    int i, j, k;

    dequant(tctx, gb, out, ftype,

            mtab->fmode[ftype].cb0, mtab->fmode[ftype].cb1,

            mtab->fmode[ftype].cb_len_read);

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

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

            for (k = 0; k < mtab->fmode[ftype].bark_n_coef; k++)

                bark1[i][j][k] =

                    get_bits(gb, mtab->fmode[ftype].bark_n_bit);

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

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

            bark_use_hist[i][j] = get_bits1(gb);

    dec_gain(tctx, gb, ftype, gain);

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

        lpc_hist_idx[i] = get_bits(gb, tctx->mtab->lsp_bit0);

        lpc_idx1    [i] = get_bits(gb, tctx->mtab->lsp_bit1);

        for (j = 0; j < tctx->mtab->lsp_split; j++)

            lpc_idx2[i][j] = get_bits(gb, tctx->mtab->lsp_bit2);

    }

    if (ftype == FT_LONG) {

        int cb_len_p = (tctx->n_div[3] + mtab->ppc_shape_len*channels - 1)/

            tctx->n_div[3];

        dequant(tctx, gb, ppc_shape, FT_PPC, mtab->ppc_shape_cb,

                mtab->ppc_shape_cb + cb_len_p*PPC_SHAPE_CB_SIZE, cb_len_p);

    }

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

        float *chunk = out + mtab->size * i;

        float lsp[LSP_COEFS_MAX];

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

            dec_bark_env(tctx, bark1[i][j], bark_use_hist[i][j], i,

                         tctx->tmp_buf, gain[sub*i+j], ftype);

            tctx->dsp.vector_fmul(chunk + block_size*j, chunk + block_size*j, tctx->tmp_buf,

                                  block_size);

        }

        if (ftype == FT_LONG) {

            float pgain_step = 25000. / ((1 << mtab->pgain_bit) - 1);

            int p_coef = get_bits(gb, tctx->mtab->ppc_period_bit);

            int g_coef = get_bits(gb, tctx->mtab->pgain_bit);

            float v = 1./8192*

                mulawinv(pgain_step*g_coef+ pgain_step/2, 25000., PGAIN_MU);

            decode_ppc(tctx, p_coef, ppc_shape + i*mtab->ppc_shape_len, v,

                       chunk);

        }

        decode_lsp(tctx, lpc_idx1[i], lpc_idx2[i], lpc_hist_idx[i], lsp,

                   tctx->lsp_hist[i]);

        dec_lpc_spectrum_inv(tctx, lsp, ftype, tctx->tmp_buf);

        for (j = 0; j < mtab->fmode[ftype].sub; j++) {

            tctx->dsp.vector_fmul(chunk, chunk, tctx->tmp_buf, block_size);

            chunk += block_size;

        }

    }

}

static int twin_decode_frame(AVCodecContext * avctx, void *data,

                             int *data_size, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    TwinContext *tctx = avctx->priv_data;

    GetBitContext gb;

    const ModeTab *mtab = tctx->mtab;

    float *out = data;

    enum FrameType ftype;

    int window_type;

    static const enum FrameType wtype_to_ftype_table[] = {

        FT_LONG,   FT_LONG, FT_SHORT, FT_LONG,

        FT_MEDIUM, FT_LONG, FT_LONG,  FT_MEDIUM, FT_MEDIUM

    };

    if (buf_size*8 < avctx->bit_rate*mtab->size/avctx->sample_rate + 8) {

        av_log(avctx, AV_LOG_ERROR,

               "Frame too small (%d bytes). Truncated file?\n", buf_size);

        *data_size = 0;

        return buf_size;

    }

    init_get_bits(&gb, buf, buf_size * 8);

    skip_bits(&gb, get_bits(&gb, 8));

    window_type = get_bits(&gb, WINDOW_TYPE_BITS);

    if (window_type > 8) {

        av_log(avctx, AV_LOG_ERROR, "Invalid window type, broken sample?\n");

        return -1;

    }

    ftype = wtype_to_ftype_table[window_type];

    read_and_decode_spectrum(tctx, &gb, tctx->spectrum, ftype);

    imdct_output(tctx, ftype, window_type, out);

    FFSWAP(float*, tctx->curr_frame, tctx->prev_frame);

    if (tctx->avctx->frame_number < 2) {

        *data_size=0;

        return buf_size;

    }

    *data_size = mtab->size*avctx->channels*4;

    return buf_size;

}

/**

 * Init IMDCT and windowing tables

 */

static av_cold void init_mdct_win(TwinContext *tctx)

{

    int i,j;

    const ModeTab *mtab = tctx->mtab;

    int size_s = mtab->size / mtab->fmode[FT_SHORT].sub;

    int size_m = mtab->size / mtab->fmode[FT_MEDIUM].sub;

    int channels = tctx->avctx->channels;

    float norm = channels == 1 ? 2. : 1.;

    for (i = 0; i < 3; i++) {

        int bsize = tctx->mtab->size/tctx->mtab->fmode[i].sub;

        ff_mdct_init(&tctx->mdct_ctx[i], av_log2(bsize) + 1, 1,

                     -sqrt(norm/bsize) / (1<<15));

    }

    tctx->tmp_buf  = av_malloc(mtab->size            * sizeof(*tctx->tmp_buf));

    tctx->spectrum  = av_malloc(2*mtab->size*channels*sizeof(float));

    tctx->curr_frame = av_malloc(2*mtab->size*channels*sizeof(float));

    tctx->prev_frame  = av_malloc(2*mtab->size*channels*sizeof(float));

    for (i = 0; i < 3; i++) {

        int m = 4*mtab->size/mtab->fmode[i].sub;

        double freq = 2*M_PI/m;

        tctx->cos_tabs[i] = av_malloc((m/4)*sizeof(*tctx->cos_tabs));

        for (j = 0; j <= m/8; j++)

            tctx->cos_tabs[i][j] = cos((2*j + 1)*freq);

        for (j = 1; j <  m/8; j++)

            tctx->cos_tabs[i][m/4-j] = tctx->cos_tabs[i][j];

    }

    ff_init_ff_sine_windows(av_log2(size_m));

    ff_init_ff_sine_windows(av_log2(size_s/2));

    ff_init_ff_sine_windows(av_log2(mtab->size));

}

/**

 * Interpret the data as if it were a num_blocks x line_len[0] matrix and for

 * each line do a cyclic permutation, i.e.

 * abcdefghijklm -> defghijklmabc

 * where the amount to be shifted is evaluated depending on the column.

 */

static void permutate_in_line(int16_t *tab, int num_vect, int num_blocks,

                              int block_size,

                              const uint8_t line_len[2], int length_div,

                              enum FrameType ftype)

{

    int i,j;

    for (i = 0; i < line_len[0]; i++) {

        int shift;

        if (num_blocks == 1 ||

            (ftype == FT_LONG && num_vect % num_blocks) ||

            (ftype != FT_LONG && num_vect & 1         ) ||

            i == line_len[1]) {

            shift = 0;

        } else if (ftype == FT_LONG) {

            shift = i;

        } else

            shift = i*i;

        for (j = 0; j < num_vect && (j+num_vect*i < block_size*num_blocks); j++)

            tab[i*num_vect+j] = i*num_vect + (j + shift) % num_vect;

    }

}

/**

 * Interpret the input data as in the following table:

 *

 * \verbatim

 *

 * abcdefgh

 * ijklmnop

 * qrstuvw

 * x123456

 *

 * \endverbatim

 *

 * and transpose it, giving the output

 * aiqxbjr1cks2dlt3emu4fvn5gow6hp

 */

static void transpose_perm(int16_t *out, int16_t *in, int num_vect,

                           const uint8_t line_len[2], int length_div)

{

    int i,j;

    int cont= 0;

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

        for (j = 0; j < line_len[i >= length_div]; j++)

            out[cont++] = in[j*num_vect + i];

}

static void linear_perm(int16_t *out, int16_t *in, int n_blocks, int size)

{

    int block_size = size/n_blocks;

    int i;

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

        out[i] = block_size * (in[i] % n_blocks) + in[i] / n_blocks;

}

static av_cold void construct_perm_table(TwinContext *tctx,enum FrameType ftype)

{

    int block_size;

    const ModeTab *mtab = tctx->mtab;

    int size = tctx->avctx->channels*mtab->fmode[ftype].sub;

    int16_t *tmp_perm = (int16_t *) tctx->tmp_buf;

    if (ftype == FT_PPC) {

        size  = tctx->avctx->channels;

        block_size = mtab->ppc_shape_len;

    } else

        block_size = mtab->size / mtab->fmode[ftype].sub;

    permutate_in_line(tmp_perm, tctx->n_div[ftype], size,

                      block_size, tctx->length[ftype],

                      tctx->length_change[ftype], ftype);

    transpose_perm(tctx->permut[ftype], tmp_perm, tctx->n_div[ftype],

                   tctx->length[ftype], tctx->length_change[ftype]);

    linear_perm(tctx->permut[ftype], tctx->permut[ftype], size,

                size*block_size);

}

static av_cold void init_bitstream_params(TwinContext *tctx)

{

    const ModeTab *mtab = tctx->mtab;

    int n_ch = tctx->avctx->channels;

    int total_fr_bits = tctx->avctx->bit_rate*mtab->size/

                             tctx->avctx->sample_rate;

    int lsp_bits_per_block = n_ch*(mtab->lsp_bit0 + mtab->lsp_bit1 +

                                   mtab->lsp_split*mtab->lsp_bit2);

    int ppc_bits = n_ch*(mtab->pgain_bit + mtab->ppc_shape_bit +

                         mtab->ppc_period_bit);

    int bsize_no_main_cb[3];

    int bse_bits[3];

    int i;

    enum FrameType frametype;

    for (i = 0; i < 3; i++)

        // +1 for history usage switch

        bse_bits[i] = n_ch *

            (mtab->fmode[i].bark_n_coef * mtab->fmode[i].bark_n_bit + 1);

    bsize_no_main_cb[2] = bse_bits[2] + lsp_bits_per_block + ppc_bits +

                          WINDOW_TYPE_BITS + n_ch*GAIN_BITS;

    for (i = 0; i < 2; i++)

        bsize_no_main_cb[i] =

            lsp_bits_per_block + n_ch*GAIN_BITS + WINDOW_TYPE_BITS +

            mtab->fmode[i].sub*(bse_bits[i] + n_ch*SUB_GAIN_BITS);

    // The remaining bits are all used for the main spectrum coefficients

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

        int bit_size;

        int vect_size;

        int rounded_up, rounded_down, num_rounded_down, num_rounded_up;

        if (i == 3) {

            bit_size  = n_ch * mtab->ppc_shape_bit;

            vect_size = n_ch * mtab->ppc_shape_len;

        } else {

            bit_size = total_fr_bits - bsize_no_main_cb[i];

            vect_size = n_ch * mtab->size;

        }

        tctx->n_div[i] = (bit_size + 13) / 14;

        rounded_up   = (bit_size + tctx->n_div[i] - 1)/tctx->n_div[i];

        rounded_down = (bit_size           )/tctx->n_div[i];

        num_rounded_down = rounded_up * tctx->n_div[i] - bit_size;

        num_rounded_up = tctx->n_div[i] - num_rounded_down;

        tctx->bits_main_spec[0][i][0] = (rounded_up   + 1)/2;

        tctx->bits_main_spec[1][i][0] = (rounded_up      )/2;

        tctx->bits_main_spec[0][i][1] = (rounded_down + 1)/2;

        tctx->bits_main_spec[1][i][1] = (rounded_down    )/2;

        tctx->bits_main_spec_change[i] = num_rounded_up;

        rounded_up   = (vect_size + tctx->n_div[i] - 1)/tctx->n_div[i];

        rounded_down = (vect_size                     )/tctx->n_div[i];

        num_rounded_down = rounded_up * tctx->n_div[i] - vect_size;

        num_rounded_up = tctx->n_div[i] - num_rounded_down;

        tctx->length[i][0] = rounded_up;

        tctx->length[i][1] = rounded_down;

        tctx->length_change[i] = num_rounded_up;

    }

    for (frametype = FT_SHORT; frametype <= FT_PPC; frametype++)

        construct_perm_table(tctx, frametype);

}

static av_cold int twin_decode_init(AVCodecContext *avctx)

{

    TwinContext *tctx = avctx->priv_data;

    int isampf = avctx->sample_rate/1000;

    int ibps = avctx->bit_rate/(1000 * avctx->channels);

    tctx->avctx       = avctx;

    avctx->sample_fmt = AV_SAMPLE_FMT_FLT;

    if (avctx->channels > CHANNELS_MAX) {

        av_log(avctx, AV_LOG_ERROR, "Unsupported number of channels: %i\n",

               avctx->channels);

        return -1;

    }

    switch ((isampf << 8) +  ibps) {

    case (8 <<8) +  8: tctx->mtab = &mode_08_08; break;

    case (11<<8) +  8: tctx->mtab = &mode_11_08; break;

    case (11<<8) + 10: tctx->mtab = &mode_11_10; break;

    case (16<<8) + 16: tctx->mtab = &mode_16_16; break;

    case (22<<8) + 20: tctx->mtab = &mode_22_20; break;

    case (22<<8) + 24: tctx->mtab = &mode_22_24; break;

    case (22<<8) + 32: tctx->mtab = &mode_22_32; break;

    case (44<<8) + 40: tctx->mtab = &mode_44_40; break;

    case (44<<8) + 48: tctx->mtab = &mode_44_48; break;

    default:

        av_log(avctx, AV_LOG_ERROR, "This version does not support %d kHz - %d kbit/s/ch mode.\n", isampf, isampf);

        return -1;

    }

    dsputil_init(&tctx->dsp, avctx);

    init_mdct_win(tctx);

    init_bitstream_params(tctx);

    memset_float(tctx->bark_hist[0][0], 0.1, FF_ARRAY_ELEMS(tctx->bark_hist));

    return 0;

}

static av_cold int twin_decode_close(AVCodecContext *avctx)

{

    TwinContext *tctx = avctx->priv_data;

    int i;

    for (i = 0; i < 3; i++) {

        ff_mdct_end(&tctx->mdct_ctx[i]);

        av_free(tctx->cos_tabs[i]);

    }

    av_free(tctx->curr_frame);

    av_free(tctx->spectrum);

    av_free(tctx->prev_frame);

    av_free(tctx->tmp_buf);

    return 0;

}

AVCodec ff_twinvq_decoder =

{

    "twinvq",

    AVMEDIA_TYPE_AUDIO,

    CODEC_ID_TWINVQ,

    sizeof(TwinContext),

    twin_decode_init,

    NULL,

    twin_decode_close,

    twin_decode_frame,

    .long_name = NULL_IF_CONFIG_SMALL("VQF TwinVQ"),

};