/*
  * 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 "libavutil/channel_layout.h"

 #include "libavutil/float_dsp.h"

 #include "avcodec.h"
 #include "get_bits.h"
 #include "dsputil.h"

 #include "fft.h"

 #include "internal.h"

 #include "lsp.h"

 #include "sinewin.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;

     AVFrame frame;

     DSPContext      dsp;

     AVFloatDSPContext fdsp;

     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];

     int discarded_packets;

 
     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 decoder: 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)
 {

     FFTContext *mdct = &tctx->mdct_ctx[ftype];

     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]];
 

         mdct->imdct_half(mdct, 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)],

                                      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;

     int size1, size2;

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

     int i;

     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 (!out)
         return;
 

     size2 = tctx->last_block_pos[0];
     size1 = mtab->size - size2;

     memcpy(&out[0][0    ], prev_buf,         size1 * sizeof(out[0][0]));
     memcpy(&out[0][size1], tctx->curr_frame, size2 * sizeof(out[0][0]));

     if (tctx->avctx->channels == 2) {
         memcpy(&out[1][0],     &prev_buf[2*mtab->size],         size1 * sizeof(out[1][0]));
         memcpy(&out[1][size1], &tctx->curr_frame[2*mtab->size], size2 * sizeof(out[1][0]));
         tctx->dsp.butterflies_float(out[0], out[1], mtab->size);

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

             chunk += block_size;
         }
     }
 }
 
 static int twin_decode_frame(AVCodecContext * avctx, void *data,

                              int *got_frame_ptr, 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 = NULL;

     enum FrameType ftype;

     int window_type, ret;

     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);

         return AVERROR(EINVAL);

     }
 

     /* get output buffer */
     if (tctx->discarded_packets >= 2) {
         tctx->frame.nb_samples = mtab->size;

         if ((ret = ff_get_buffer(avctx, &tctx->frame)) < 0) {

             av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
             return ret;
         }

         out = (float **)tctx->frame.extended_data;

     }
 
     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->discarded_packets < 2) {
         tctx->discarded_packets++;
         *got_frame_ptr = 0;

         return buf_size;
     }
 

     *got_frame_ptr   = 1;

     *(AVFrame *)data = tctx->frame;

 
     return buf_size;
 }
 
 /**
  * Init IMDCT and windowing tables
  */

 static av_cold int init_mdct_win(TwinContext *tctx)

 {

     int i, j, ret;

     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;

         if ((ret = ff_mdct_init(&tctx->mdct_ctx[i], av_log2(bsize) + 1, 1,
                                 -sqrt(norm/bsize) / (1<<15))))
             return ret;

     }
 

     FF_ALLOC_OR_GOTO(tctx->avctx, tctx->tmp_buf,
                      mtab->size * sizeof(*tctx->tmp_buf), alloc_fail);

     FF_ALLOC_OR_GOTO(tctx->avctx, tctx->spectrum,
                      2 * mtab->size * channels * sizeof(*tctx->spectrum),
                      alloc_fail);
     FF_ALLOC_OR_GOTO(tctx->avctx, tctx->curr_frame,
                      2 * mtab->size * channels * sizeof(*tctx->curr_frame),
                      alloc_fail);
     FF_ALLOC_OR_GOTO(tctx->avctx, tctx->prev_frame,
                      2 * mtab->size * channels * sizeof(*tctx->prev_frame),
                      alloc_fail);

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

         int m = 4*mtab->size/mtab->fmode[i].sub;
         double freq = 2*M_PI/m;

         FF_ALLOC_OR_GOTO(tctx->avctx, tctx->cos_tabs[i],
                          (m / 4) * sizeof(*tctx->cos_tabs[i]), alloc_fail);

         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));

 
     return 0;
 alloc_fail:
     return AVERROR(ENOMEM);

 }
 
 /**
  * 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;

     int16_t *tmp_perm = (int16_t *) tctx->tmp_buf;
 
     if (ftype == FT_PPC) {
         size  = tctx->avctx->channels;
         block_size = mtab->ppc_shape_len;

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

         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_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;
 }
 

 static av_cold int twin_decode_init(AVCodecContext *avctx)
 {

     int ret;

     TwinContext *tctx = avctx->priv_data;

     int isampf, ibps;

 
     tctx->avctx       = avctx;

     avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;

     if (!avctx->extradata || avctx->extradata_size < 12) {
         av_log(avctx, AV_LOG_ERROR, "Missing or incomplete extradata\n");
         return AVERROR_INVALIDDATA;
     }
     avctx->channels = AV_RB32(avctx->extradata    ) + 1;
     avctx->bit_rate = AV_RB32(avctx->extradata + 4) * 1000;
     isampf          = AV_RB32(avctx->extradata + 8);

 
     if (isampf < 8 || isampf > 44) {
         av_log(avctx, AV_LOG_ERROR, "Unsupported sample rate\n");
         return AVERROR_INVALIDDATA;
     }

     switch (isampf) {
     case 44: avctx->sample_rate = 44100;         break;
     case 22: avctx->sample_rate = 22050;         break;
     case 11: avctx->sample_rate = 11025;         break;
     default: avctx->sample_rate = isampf * 1000; break;
     }
 

     if (avctx->channels <= 0 || avctx->channels > CHANNELS_MAX) {

         av_log(avctx, AV_LOG_ERROR, "Unsupported number of channels: %i\n",
                avctx->channels);
         return -1;
     }

     avctx->channel_layout = avctx->channels == 1 ? AV_CH_LAYOUT_MONO :
                                                    AV_CH_LAYOUT_STEREO;
 

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

     if (ibps > 255U) {

         av_log(avctx, AV_LOG_ERROR, "unsupported per channel bitrate %dkbps\n", ibps);
         return AVERROR_INVALIDDATA;
     }
 

     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;
     }
 

     ff_dsputil_init(&tctx->dsp, avctx);

     avpriv_float_dsp_init(&tctx->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);

     if ((ret = init_mdct_win(tctx))) {
         av_log(avctx, AV_LOG_ERROR, "Error initializing MDCT\n");
         twin_decode_close(avctx);
         return ret;
     }

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

     avcodec_get_frame_defaults(&tctx->frame);
     avctx->coded_frame = &tctx->frame;
 

     return 0;
 }
 

 AVCodec ff_twinvq_decoder = {
     .name           = "twinvq",
     .type           = AVMEDIA_TYPE_AUDIO,

     .id             = AV_CODEC_ID_TWINVQ,

     .priv_data_size = sizeof(TwinContext),
     .init           = twin_decode_init,
     .close          = twin_decode_close,
     .decode         = twin_decode_frame,

     .capabilities   = CODEC_CAP_DR1,

     .long_name      = NULL_IF_CONFIG_SMALL("VQF TwinVQ"),

     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
                                                       AV_SAMPLE_FMT_NONE },

 };