/*
  * IMC compatible decoder
  * Copyright (c) 2002-2004 Maxim Poliakovski
  * Copyright (c) 2006 Benjamin Larsson
  * Copyright (c) 2006 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
  */
 
 /**

  *  @file
  *  IMC - Intel Music Coder

  *  A mdct based codec using a 256 points large transform

  *  divided into 32 bands with some mix of scale factors.

  *  Only mono is supported.
  *
  */
 
 
 #include <math.h>
 #include <stddef.h>
 #include <stdio.h>
 

 #include "libavutil/channel_layout.h"

 #include "libavutil/float_dsp.h"

 #include "libavutil/internal.h"

 #include "libavutil/libm.h"

 #include "avcodec.h"

 #include "get_bits.h"

 #include "dsputil.h"

 #include "fft.h"

 #include "internal.h"

 #include "sinewin.h"

 
 #include "imcdata.h"
 

 #define IMC_BLOCK_SIZE 64

 #define IMC_FRAME_ID 0x21
 #define BANDS 32
 #define COEFFS 256
 

 typedef struct IMCChannel {

     float old_floor[BANDS];
     float flcoeffs1[BANDS];
     float flcoeffs2[BANDS];
     float flcoeffs3[BANDS];
     float flcoeffs4[BANDS];
     float flcoeffs5[BANDS];
     float flcoeffs6[BANDS];
     float CWdecoded[COEFFS];
 
     int bandWidthT[BANDS];     ///< codewords per band
     int bitsBandT[BANDS];      ///< how many bits per codeword in band
     int CWlengthT[COEFFS];     ///< how many bits in each codeword
     int levlCoeffBuf[BANDS];
     int bandFlagsBuf[BANDS];   ///< flags for each band
     int sumLenArr[BANDS];      ///< bits for all coeffs in band
     int skipFlagRaw[BANDS];    ///< skip flags are stored in raw form or not
     int skipFlagBits[BANDS];   ///< bits used to code skip flags
     int skipFlagCount[BANDS];  ///< skipped coeffients per band
     int skipFlags[COEFFS];     ///< skip coefficient decoding or not
     int codewords[COEFFS];     ///< raw codewords read from bitstream

 
     float last_fft_im[COEFFS];
 
     int decoder_reset;
 } IMCChannel;
 
 typedef struct {

     IMCChannel chctx[2];

 
     /** MDCT tables */
     //@{
     float mdct_sine_window[COEFFS];
     float post_cos[COEFFS];
     float post_sin[COEFFS];
     float pre_coef1[COEFFS];
     float pre_coef2[COEFFS];
     //@}
 

     float sqrt_tab[30];
     GetBitContext gb;
 
     DSPContext dsp;

     AVFloatDSPContext fdsp;

     FFTContext fft;

     DECLARE_ALIGNED(32, FFTComplex, samples)[COEFFS / 2];

     float *out_samples;

     int coef0_pos;
 

     int8_t cyclTab[32], cyclTab2[32];
     float  weights1[31], weights2[31];

 } IMCContext;
 

 static VLC huffman_vlc[4][4];
 
 #define VLC_TABLES_SIZE 9512
 
 static const int vlc_offsets[17] = {
     0,     640, 1156, 1732, 2308, 2852, 3396, 3924,

     4452, 5220, 5860, 6628, 7268, 7908, 8424, 8936, VLC_TABLES_SIZE
 };

 
 static VLC_TYPE vlc_tables[VLC_TABLES_SIZE][2];

 static inline double freq2bark(double freq)
 {
     return 3.5 * atan((freq / 7500.0) * (freq / 7500.0)) + 13.0 * atan(freq * 0.00076);
 }
 
 static av_cold void iac_generate_tabs(IMCContext *q, int sampling_rate)
 {
     double freqmin[32], freqmid[32], freqmax[32];
     double scale = sampling_rate / (256.0 * 2.0 * 2.0);
     double nyquist_freq = sampling_rate * 0.5;
     double freq, bark, prev_bark = 0, tf, tb;
     int i, j;
 
     for (i = 0; i < 32; i++) {
         freq = (band_tab[i] + band_tab[i + 1] - 1) * scale;
         bark = freq2bark(freq);
 
         if (i > 0) {
             tb = bark - prev_bark;
             q->weights1[i - 1] = pow(10.0, -1.0 * tb);
             q->weights2[i - 1] = pow(10.0, -2.7 * tb);
         }
         prev_bark = bark;
 
         freqmid[i] = freq;
 
         tf = freq;
         while (tf < nyquist_freq) {
             tf += 0.5;
             tb =  freq2bark(tf);
             if (tb > bark + 0.5)
                 break;
         }
         freqmax[i] = tf;
 
         tf = freq;
         while (tf > 0.0) {
             tf -= 0.5;
             tb =  freq2bark(tf);
             if (tb <= bark - 0.5)
                 break;
         }
         freqmin[i] = tf;
     }
 
     for (i = 0; i < 32; i++) {
         freq = freqmax[i];
         for (j = 31; j > 0 && freq <= freqmid[j]; j--);
         q->cyclTab[i] = j + 1;
 
         freq = freqmin[i];
         for (j = 0; j < 32 && freq >= freqmid[j]; j++);
         q->cyclTab2[i] = j - 1;
     }
 }
 

 static av_cold int imc_decode_init(AVCodecContext *avctx)

 {

     int i, j, ret;

     IMCContext *q = avctx->priv_data;
     double r1, r2;
 

     if (avctx->codec_id == AV_CODEC_ID_IMC)
         avctx->channels = 1;
 
     if (avctx->channels > 2) {

         avpriv_request_sample(avctx, "Number of channels > 2");

         return AVERROR_PATCHWELCOME;
     }
 

     for (j = 0; j < avctx->channels; j++) {
         q->chctx[j].decoder_reset = 1;

         for (i = 0; i < BANDS; i++)
             q->chctx[j].old_floor[i] = 1.0;
 
         for (i = 0; i < COEFFS / 2; i++)
             q->chctx[j].last_fft_im[i] = 0;
     }

 
     /* Build mdct window, a simple sine window normalized with sqrt(2) */

     ff_sine_window_init(q->mdct_sine_window, COEFFS);

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

         q->mdct_sine_window[i] *= sqrt(2.0);

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

         q->post_cos[i] = (1.0f / 32768) * cos(i / 256.0 * M_PI);
         q->post_sin[i] = (1.0f / 32768) * sin(i / 256.0 * M_PI);

 
         r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI);
         r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI);
 

         if (i & 0x1) {

             q->pre_coef1[i] =  (r1 + r2) * sqrt(2.0);
             q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);

         } else {

             q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);
             q->pre_coef2[i] =  (r1 - r2) * sqrt(2.0);
         }
     }
 
     /* Generate a square root table */
 

     for (i = 0; i < 30; i++)

         q->sqrt_tab[i] = sqrt(i);
 
     /* initialize the VLC tables */

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

             huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]];

             huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];
             init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i],

                      imc_huffman_lens[i][j], 1, 1,

                      imc_huffman_bits[i][j], 2, 2, INIT_VLC_USE_NEW_STATIC);

         }
     }

     if (avctx->codec_id == AV_CODEC_ID_IAC) {

         iac_generate_tabs(q, avctx->sample_rate);

     } else {

         memcpy(q->cyclTab,  cyclTab,  sizeof(cyclTab));
         memcpy(q->cyclTab2, cyclTab2, sizeof(cyclTab2));

         memcpy(q->weights1, imc_weights1, sizeof(imc_weights1));
         memcpy(q->weights2, imc_weights2, sizeof(imc_weights2));
     }
 

     if ((ret = ff_fft_init(&q->fft, 7, 1))) {
         av_log(avctx, AV_LOG_INFO, "FFT init failed\n");
         return ret;
     }

     ff_dsputil_init(&q->dsp, avctx);

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

     avctx->sample_fmt     = AV_SAMPLE_FMT_FLTP;

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

     return 0;
 }
 

 static void imc_calculate_coeffs(IMCContext *q, float *flcoeffs1,
                                  float *flcoeffs2, int *bandWidthT,
                                  float *flcoeffs3, float *flcoeffs5)

 {
     float   workT1[BANDS];
     float   workT2[BANDS];
     float   workT3[BANDS];
     float   snr_limit = 1.e-30;
     float   accum = 0.0;
     int i, cnt2;
 

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

         flcoeffs5[i] = workT2[i] = 0.0;

         if (bandWidthT[i]) {

             workT1[i] = flcoeffs1[i] * flcoeffs1[i];
             flcoeffs3[i] = 2.0 * flcoeffs2[i];
         } else {

             workT1[i]    = 0.0;

             flcoeffs3[i] = -30000.0;
         }
         workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
         if (workT3[i] <= snr_limit)
             workT3[i] = 0.0;
     }
 

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

         for (cnt2 = i; cnt2 < q->cyclTab[i]; cnt2++)

             flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i];

         workT2[cnt2 - 1] = workT2[cnt2 - 1] + workT3[i];

     }
 

     for (i = 1; i < BANDS; i++) {

         accum = (workT2[i - 1] + accum) * q->weights1[i - 1];

         flcoeffs5[i] += accum;
     }
 

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

         workT2[i] = 0.0;
 

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

         for (cnt2 = i - 1; cnt2 > q->cyclTab2[i]; cnt2--)

             flcoeffs5[cnt2] += workT3[i];
         workT2[cnt2+1] += workT3[i];
     }
 
     accum = 0.0;
 

     for (i = BANDS-2; i >= 0; i--) {

         accum = (workT2[i+1] + accum) * q->weights2[i];

         flcoeffs5[i] += accum;

         // there is missing code here, but it seems to never be triggered

     }
 }
 
 

 static void imc_read_level_coeffs(IMCContext *q, int stream_format_code,
                                   int *levlCoeffs)

 {
     int i;
     VLC *hufftab[4];
     int start = 0;
     const uint8_t *cb_sel;
     int s;
 
     s = stream_format_code >> 1;

     hufftab[0] = &huffman_vlc[s][0];
     hufftab[1] = &huffman_vlc[s][1];
     hufftab[2] = &huffman_vlc[s][2];
     hufftab[3] = &huffman_vlc[s][3];

     cb_sel = imc_cb_select[s];
 

     if (stream_format_code & 4)

         start = 1;

     if (start)

         levlCoeffs[0] = get_bits(&q->gb, 7);

     for (i = start; i < BANDS; i++) {
         levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table,
                                  hufftab[cb_sel[i]]->bits, 2);
         if (levlCoeffs[i] == 17)

             levlCoeffs[i] += get_bits(&q->gb, 4);
     }
 }
 

 static void imc_read_level_coeffs_raw(IMCContext *q, int stream_format_code,
                                       int *levlCoeffs)
 {
     int i;
 
     q->coef0_pos  = get_bits(&q->gb, 5);
     levlCoeffs[0] = get_bits(&q->gb, 7);
     for (i = 1; i < BANDS; i++)
         levlCoeffs[i] = get_bits(&q->gb, 4);
 }
 

 static void imc_decode_level_coefficients(IMCContext *q, int *levlCoeffBuf,
                                           float *flcoeffs1, float *flcoeffs2)

 {
     int i, level;
     float tmp, tmp2;

     // maybe some frequency division thingy

     flcoeffs1[0] = 20000.0 / exp2 (levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125

     flcoeffs2[0] = log2f(flcoeffs1[0]);

     tmp  = flcoeffs1[0];

     tmp2 = flcoeffs2[0];
 

     for (i = 1; i < BANDS; i++) {

         level = levlCoeffBuf[i];
         if (level == 16) {
             flcoeffs1[i] = 1.0;
             flcoeffs2[i] = 0.0;
         } else {
             if (level < 17)

                 level -= 7;

             else if (level <= 24)

                 level -= 32;

             else

                 level -= 16;

 
             tmp  *= imc_exp_tab[15 + level];

             tmp2 += 0.83048 * level;  // 0.83048 = log2(10) * 0.25

             flcoeffs1[i] = tmp;
             flcoeffs2[i] = tmp2;
         }
     }
 }
 
 

 static void imc_decode_level_coefficients2(IMCContext *q, int *levlCoeffBuf,
                                            float *old_floor, float *flcoeffs1,
                                            float *flcoeffs2)
 {

     int i;

     /* FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
      *       and flcoeffs2 old scale factors
      *       might be incomplete due to a missing table that is in the binary code
      */
     for (i = 0; i < BANDS; i++) {

         flcoeffs1[i] = 0;

         if (levlCoeffBuf[i] < 16) {

             flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];

             flcoeffs2[i] = (levlCoeffBuf[i] - 7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25

         } else {
             flcoeffs1[i] = old_floor[i];
         }
     }
 }
 

 static void imc_decode_level_coefficients_raw(IMCContext *q, int *levlCoeffBuf,
                                               float *flcoeffs1, float *flcoeffs2)
 {
     int i, level, pos;
     float tmp, tmp2;
 
     pos = q->coef0_pos;
     flcoeffs1[pos] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
     flcoeffs2[pos] = log2f(flcoeffs1[0]);
     tmp  = flcoeffs1[pos];
     tmp2 = flcoeffs2[pos];
 
     levlCoeffBuf++;
     for (i = 0; i < BANDS; i++) {
         if (i == pos)
             continue;
         level = *levlCoeffBuf++;
         flcoeffs1[i] = tmp  * powf(10.0, -level * 0.4375); //todo tab
         flcoeffs2[i] = tmp2 - 1.4533435415 * level; // 1.4533435415 = log2(10) * 0.4375
     }
 }
 

 /**
  * Perform bit allocation depending on bits available
  */

 static int bit_allocation(IMCContext *q, IMCChannel *chctx,
                           int stream_format_code, int freebits, int flag)

 {

     int i, j;
     const float limit = -1.e20;
     float highest = 0.0;
     int indx;
     int t1 = 0;
     int t2 = 1;
     float summa = 0.0;
     int iacc = 0;
     int summer = 0;
     int rres, cwlen;
     float lowest = 1.e10;
     int low_indx = 0;
     float workT[32];
     int flg;
     int found_indx = 0;
 

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

         highest = FFMAX(highest, chctx->flcoeffs1[i]);

     for (i = 0; i < BANDS - 1; i++) {
         if (chctx->flcoeffs5[i] <= 0) {
             av_log(NULL, AV_LOG_ERROR, "flcoeffs5 %f invalid\n", chctx->flcoeffs5[i]);
             return AVERROR_INVALIDDATA;
         }

         chctx->flcoeffs4[i] = chctx->flcoeffs3[i] - log2f(chctx->flcoeffs5[i]);

     }

     chctx->flcoeffs4[BANDS - 1] = limit;

 
     highest = highest * 0.25;
 

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

         indx = -1;

         if ((band_tab[i + 1] - band_tab[i]) == chctx->bandWidthT[i])

             indx = 0;
 

         if ((band_tab[i + 1] - band_tab[i]) > chctx->bandWidthT[i])

             indx = 1;
 

         if (((band_tab[i + 1] - band_tab[i]) / 2) >= chctx->bandWidthT[i])

             indx = 2;
 
         if (indx == -1)

             return AVERROR_INVALIDDATA;

         chctx->flcoeffs4[i] += xTab[(indx * 2 + (chctx->flcoeffs1[i] < highest)) * 2 + flag];

     }
 
     if (stream_format_code & 0x2) {

         chctx->flcoeffs4[0] = limit;
         chctx->flcoeffs4[1] = limit;
         chctx->flcoeffs4[2] = limit;
         chctx->flcoeffs4[3] = limit;

     }
 

     for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS - 1; i++) {

         iacc  += chctx->bandWidthT[i];
         summa += chctx->bandWidthT[i] * chctx->flcoeffs4[i];

     }

 
     if (!iacc)
         return AVERROR_INVALIDDATA;
 

     chctx->bandWidthT[BANDS - 1] = 0;

     summa = (summa * 0.5 - freebits) / iacc;
 
 

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

         rres = summer - freebits;

         if ((rres >= -8) && (rres <= 8))
             break;

 
         summer = 0;

         iacc   = 0;

         for (j = (stream_format_code & 0x2) ? 4 : 0; j < BANDS; j++) {

             cwlen = av_clipf(((chctx->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);

             chctx->bitsBandT[j] = cwlen;
             summer += chctx->bandWidthT[j] * cwlen;

 
             if (cwlen > 0)

                 iacc += chctx->bandWidthT[j];

         }
 
         flg = t2;
         t2 = 1;
         if (freebits < summer)
             t2 = -1;
         if (i == 0)
             flg = t2;

         if (flg != t2)

             t1++;
 
         summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
     }
 

     for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS; i++) {
         for (j = band_tab[i]; j < band_tab[i + 1]; j++)

             chctx->CWlengthT[j] = chctx->bitsBandT[i];

     }
 
     if (freebits > summer) {

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

             workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20
                                               : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);

         }
 
         highest = 0.0;
 

         do {

             if (highest <= -1.e20)
                 break;
 
             found_indx = 0;
             highest = -1.e20;
 

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

                 if (workT[i] > highest) {
                     highest = workT[i];
                     found_indx = i;
                 }
             }
 
             if (highest > -1.e20) {
                 workT[found_indx] -= 2.0;

                 if (++chctx->bitsBandT[found_indx] == 6)

                     workT[found_indx] = -1.e20;
 

                 for (j = band_tab[found_indx]; j < band_tab[found_indx + 1] && (freebits > summer); j++) {

                     chctx->CWlengthT[j]++;

                     summer++;
                 }
             }

         } while (freebits > summer);

     }
     if (freebits < summer) {

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

             workT[i] = chctx->bitsBandT[i] ? (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] + 1.585)

                                        : 1.e20;

         }
         if (stream_format_code & 0x2) {
             workT[0] = 1.e20;
             workT[1] = 1.e20;
             workT[2] = 1.e20;
             workT[3] = 1.e20;
         }

         while (freebits < summer) {
             lowest   = 1.e10;

             low_indx = 0;

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

                 if (workT[i] < lowest) {

                     lowest   = workT[i];

                     low_indx = i;
                 }
             }

             // if (lowest >= 1.e10)
             //     break;

             workT[low_indx] = lowest + 2.0;
 

             if (!--chctx->bitsBandT[low_indx])

                 workT[low_indx] = 1.e20;
 

             for (j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++) {

                 if (chctx->CWlengthT[j] > 0) {
                     chctx->CWlengthT[j]--;

                     summer--;
                 }
             }
         }
     }
     return 0;
 }
 

 static void imc_get_skip_coeff(IMCContext *q, IMCChannel *chctx)

 {

     int i, j;
 

     memset(chctx->skipFlagBits,  0, sizeof(chctx->skipFlagBits));
     memset(chctx->skipFlagCount, 0, sizeof(chctx->skipFlagCount));

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

         if (!chctx->bandFlagsBuf[i] || !chctx->bandWidthT[i])

             continue;
 

         if (!chctx->skipFlagRaw[i]) {
             chctx->skipFlagBits[i] = band_tab[i + 1] - band_tab[i];

             for (j = band_tab[i]; j < band_tab[i + 1]; j++) {

                 chctx->skipFlags[j] = get_bits1(&q->gb);
                 if (chctx->skipFlags[j])
                     chctx->skipFlagCount[i]++;

             }
         } else {

             for (j = band_tab[i]; j < band_tab[i + 1] - 1; j += 2) {
                 if (!get_bits1(&q->gb)) { // 0

                     chctx->skipFlagBits[i]++;
                     chctx->skipFlags[j]      = 1;
                     chctx->skipFlags[j + 1]  = 1;
                     chctx->skipFlagCount[i] += 2;

                 } else {
                     if (get_bits1(&q->gb)) { // 11

                         chctx->skipFlagBits[i] += 2;
                         chctx->skipFlags[j]     = 0;
                         chctx->skipFlags[j + 1] = 1;
                         chctx->skipFlagCount[i]++;

                     } else {

                         chctx->skipFlagBits[i] += 3;
                         chctx->skipFlags[j + 1] = 0;

                         if (!get_bits1(&q->gb)) { // 100

                             chctx->skipFlags[j] = 1;
                             chctx->skipFlagCount[i]++;

                         } else { // 101

                             chctx->skipFlags[j] = 0;

                         }
                     }
                 }
             }
 

             if (j < band_tab[i + 1]) {

                 chctx->skipFlagBits[i]++;
                 if ((chctx->skipFlags[j] = get_bits1(&q->gb)))
                     chctx->skipFlagCount[i]++;

             }
         }
     }
 }
 
 /**
  * Increase highest' band coefficient sizes as some bits won't be used
  */

 static void imc_adjust_bit_allocation(IMCContext *q, IMCChannel *chctx,
                                       int summer)

 {

     float workT[32];
     int corrected = 0;
     int i, j;

     float highest  = 0;
     int found_indx = 0;

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

         workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20
                                           : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);

     }
 
     while (corrected < summer) {

         if (highest <= -1.e20)

             break;
 
         highest = -1.e20;
 

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

             if (workT[i] > highest) {
                 highest = workT[i];
                 found_indx = i;
             }
         }
 
         if (highest > -1.e20) {
             workT[found_indx] -= 2.0;

             if (++(chctx->bitsBandT[found_indx]) == 6)

                 workT[found_indx] = -1.e20;
 

             for (j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {

                 if (!chctx->skipFlags[j] && (chctx->CWlengthT[j] < 6)) {
                     chctx->CWlengthT[j]++;

                     corrected++;
                 }
             }
         }
     }
 }
 

 static void imc_imdct256(IMCContext *q, IMCChannel *chctx, int channels)

 {

     int i;
     float re, im;

     float *dst1 = q->out_samples;

     float *dst2 = q->out_samples + (COEFFS - 1);

 
     /* prerotation */

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

         q->samples[i].re = -(q->pre_coef1[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -
                             (q->pre_coef2[i] * chctx->CWdecoded[i * 2]);
         q->samples[i].im =  (q->pre_coef2[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -
                             (q->pre_coef1[i] * chctx->CWdecoded[i * 2]);

     }
 
     /* FFT */

     q->fft.fft_permute(&q->fft, q->samples);

     q->fft.fft_calc(&q->fft, q->samples);

 
     /* postrotation, window and reorder */

     for (i = 0; i < COEFFS / 2; i++) {
         re = ( q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
         im = (-q->samples[i].im * q->post_cos[i]) - ( q->samples[i].re * q->post_sin[i]);

         *dst1 =  (q->mdct_sine_window[COEFFS - 1 - i * 2] * chctx->last_fft_im[i])
                + (q->mdct_sine_window[i * 2] * re);
         *dst2 =  (q->mdct_sine_window[i * 2] * chctx->last_fft_im[i])
                - (q->mdct_sine_window[COEFFS - 1 - i * 2] * re);

         dst1 += 2;
         dst2 -= 2;

         chctx->last_fft_im[i] = im;

     }
 }
 

 static int inverse_quant_coeff(IMCContext *q, IMCChannel *chctx,
                                int stream_format_code)

 {

     int i, j;
     int middle_value, cw_len, max_size;

     const float *quantizer;

     for (i = 0; i < BANDS; i++) {
         for (j = band_tab[i]; j < band_tab[i + 1]; j++) {

             chctx->CWdecoded[j] = 0;
             cw_len = chctx->CWlengthT[j];

             if (cw_len <= 0 || chctx->skipFlags[j])

                 continue;
 

             max_size     = 1 << cw_len;

             middle_value = max_size >> 1;
 

             if (chctx->codewords[j] >= max_size || chctx->codewords[j] < 0)

                 return AVERROR_INVALIDDATA;

             if (cw_len >= 4) {

                 quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];

                 if (chctx->codewords[j] >= middle_value)
                     chctx->CWdecoded[j] =  quantizer[chctx->codewords[j] - 8]                * chctx->flcoeffs6[i];

                 else

                     chctx->CWdecoded[j] = -quantizer[max_size - chctx->codewords[j] - 8 - 1] * chctx->flcoeffs6[i];

             }else{

                 quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (chctx->bandFlagsBuf[i] << 1)];
                 if (chctx->codewords[j] >= middle_value)
                     chctx->CWdecoded[j] =  quantizer[chctx->codewords[j] - 1]            * chctx->flcoeffs6[i];

                 else

                     chctx->CWdecoded[j] = -quantizer[max_size - 2 - chctx->codewords[j]] * chctx->flcoeffs6[i];

             }
         }
     }
     return 0;
 }
 
 

 static int imc_get_coeffs(IMCContext *q, IMCChannel *chctx)

 {

     int i, j, cw_len, cw;
 

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

         if (!chctx->sumLenArr[i])

             continue;

         if (chctx->bandFlagsBuf[i] || chctx->bandWidthT[i]) {

             for (j = band_tab[i]; j < band_tab[i + 1]; j++) {

                 cw_len = chctx->CWlengthT[j];

                 cw = 0;
 

                 if (get_bits_count(&q->gb) + cw_len > 512) {

                     av_dlog(NULL, "Band %i coeff %i cw_len %i\n", i, j, cw_len);

                     return AVERROR_INVALIDDATA;

                 }
 

                 if (cw_len && (!chctx->bandFlagsBuf[i] || !chctx->skipFlags[j]))

                     cw = get_bits(&q->gb, cw_len);
 

                 chctx->codewords[j] = cw;

             }
         }
     }
     return 0;
 }
 

 static void imc_refine_bit_allocation(IMCContext *q, IMCChannel *chctx)
 {
     int i, j;
     int bits, summer;
 
     for (i = 0; i < BANDS; i++) {
         chctx->sumLenArr[i]   = 0;
         chctx->skipFlagRaw[i] = 0;
         for (j = band_tab[i]; j < band_tab[i + 1]; j++)
             chctx->sumLenArr[i] += chctx->CWlengthT[j];
         if (chctx->bandFlagsBuf[i])
             if ((((band_tab[i + 1] - band_tab[i]) * 1.5) > chctx->sumLenArr[i]) && (chctx->sumLenArr[i] > 0))
                 chctx->skipFlagRaw[i] = 1;
     }
 
     imc_get_skip_coeff(q, chctx);
 
     for (i = 0; i < BANDS; i++) {
         chctx->flcoeffs6[i] = chctx->flcoeffs1[i];
         /* band has flag set and at least one coded coefficient */
         if (chctx->bandFlagsBuf[i] && (band_tab[i + 1] - band_tab[i]) != chctx->skipFlagCount[i]) {
             chctx->flcoeffs6[i] *= q->sqrt_tab[ band_tab[i + 1] - band_tab[i]] /
                                    q->sqrt_tab[(band_tab[i + 1] - band_tab[i] - chctx->skipFlagCount[i])];
         }
     }
 
     /* calculate bits left, bits needed and adjust bit allocation */
     bits = summer = 0;
 
     for (i = 0; i < BANDS; i++) {
         if (chctx->bandFlagsBuf[i]) {
             for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
                 if (chctx->skipFlags[j]) {
                     summer += chctx->CWlengthT[j];
                     chctx->CWlengthT[j] = 0;
                 }
             }
             bits   += chctx->skipFlagBits[i];
             summer -= chctx->skipFlagBits[i];
         }
     }
     imc_adjust_bit_allocation(q, chctx, summer);
 }
 

 static int imc_decode_block(AVCodecContext *avctx, IMCContext *q, int ch)

 {
     int stream_format_code;

     int imc_hdr, i, j, ret;

     int flag;

     int bits;

     int counter, bitscount;

     IMCChannel *chctx = q->chctx + ch;

 
 
     /* Check the frame header */
     imc_hdr = get_bits(&q->gb, 9);

     if (imc_hdr & 0x18) {
         av_log(avctx, AV_LOG_ERROR, "frame header check failed!\n");
         av_log(avctx, AV_LOG_ERROR, "got %X.\n", imc_hdr);

         return AVERROR_INVALIDDATA;

     }
     stream_format_code = get_bits(&q->gb, 3);
 
     if (stream_format_code & 0x04)

         chctx->decoder_reset = 1;

     if (chctx->decoder_reset) {

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

             chctx->old_floor[i] = 1.0;

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

             chctx->CWdecoded[i] = 0;
         chctx->decoder_reset = 0;

     }
 
     flag = get_bits1(&q->gb);

     if (stream_format_code & 0x1)
         imc_decode_level_coefficients_raw(q, chctx->levlCoeffBuf,
                                           chctx->flcoeffs1, chctx->flcoeffs2);
     else if (stream_format_code & 0x1)
         imc_read_level_coeffs_raw(q, stream_format_code, chctx->levlCoeffBuf);
     else
         imc_read_level_coeffs(q, stream_format_code, chctx->levlCoeffBuf);

 
     if (stream_format_code & 0x4)

         imc_decode_level_coefficients(q, chctx->levlCoeffBuf,
                                       chctx->flcoeffs1, chctx->flcoeffs2);

     else

         imc_decode_level_coefficients2(q, chctx->levlCoeffBuf, chctx->old_floor,
                                        chctx->flcoeffs1, chctx->flcoeffs2);

     for(i=0; i<BANDS; i++) {
         if(chctx->flcoeffs1[i] > INT_MAX) {
             av_log(avctx, AV_LOG_ERROR, "scalefactor out of range\n");
             return AVERROR_INVALIDDATA;
         }
     }
 

     memcpy(chctx->old_floor, chctx->flcoeffs1, 32 * sizeof(float));

 
     counter = 0;

     if (stream_format_code & 0x1) {
         for (i = 0; i < BANDS; i++) {
             chctx->bandWidthT[i]   = band_tab[i + 1] - band_tab[i];
             chctx->bandFlagsBuf[i] = 0;
             chctx->flcoeffs3[i]    = chctx->flcoeffs2[i] * 2;
             chctx->flcoeffs5[i]    = 1.0;
         }
     } else {
         for (i = 0; i < BANDS; i++) {
             if (chctx->levlCoeffBuf[i] == 16) {
                 chctx->bandWidthT[i] = 0;
                 counter++;
             } else
                 chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];
         }
 
         memset(chctx->bandFlagsBuf, 0, BANDS * sizeof(int));
         for (i = 0; i < BANDS - 1; i++)
             if (chctx->bandWidthT[i])
                 chctx->bandFlagsBuf[i] = get_bits1(&q->gb);

         imc_calculate_coeffs(q, chctx->flcoeffs1, chctx->flcoeffs2,
                              chctx->bandWidthT, chctx->flcoeffs3,
                              chctx->flcoeffs5);
     }

 
     bitscount = 0;
     /* first 4 bands will be assigned 5 bits per coefficient */
     if (stream_format_code & 0x2) {
         bitscount += 15;
 

         chctx->bitsBandT[0] = 5;
         chctx->CWlengthT[0] = 5;
         chctx->CWlengthT[1] = 5;
         chctx->CWlengthT[2] = 5;

         for (i = 1; i < 4; i++) {

             if (stream_format_code & 0x1)
                 bits = 5;
             else
                 bits = (chctx->levlCoeffBuf[i] == 16) ? 0 : 5;

             chctx->bitsBandT[i] = bits;

             for (j = band_tab[i]; j < band_tab[i + 1]; j++) {

                 chctx->CWlengthT[j] = bits;

                 bitscount      += bits;

             }
         }
     }

     if (avctx->codec_id == AV_CODEC_ID_IAC) {

         bitscount += !!chctx->bandWidthT[BANDS - 1];
         if (!(stream_format_code & 0x2))
             bitscount += 16;
     }

     if ((ret = bit_allocation(q, chctx, stream_format_code,

                               512 - bitscount - get_bits_count(&q->gb),
                               flag)) < 0) {

         av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");

         chctx->decoder_reset = 1;

         return ret;

     }
 

     if (stream_format_code & 0x1) {
         for (i = 0; i < BANDS; i++)
             chctx->skipFlags[i] = 0;
     } else {
         imc_refine_bit_allocation(q, chctx);

     }
 

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

         chctx->sumLenArr[i] = 0;

         for (j = band_tab[i]; j < band_tab[i + 1]; j++)

             if (!chctx->skipFlags[j])
                 chctx->sumLenArr[i] += chctx->CWlengthT[j];

     }
 

     memset(chctx->codewords, 0, sizeof(chctx->codewords));

     if (imc_get_coeffs(q, chctx) < 0) {

         av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");

         chctx->decoder_reset = 1;

         return AVERROR_INVALIDDATA;

     }
 

     if (inverse_quant_coeff(q, chctx, stream_format_code) < 0) {

         av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");

         chctx->decoder_reset = 1;

         return AVERROR_INVALIDDATA;

     }
 

     memset(chctx->skipFlags, 0, sizeof(chctx->skipFlags));
 

     imc_imdct256(q, chctx, avctx->channels);

 
     return 0;
 }
 
 static int imc_decode_frame(AVCodecContext *avctx, void *data,
                             int *got_frame_ptr, AVPacket *avpkt)
 {

     AVFrame *frame     = data;

     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;
     int ret, i;

     IMCContext *q = avctx->priv_data;
 
     LOCAL_ALIGNED_16(uint16_t, buf16, [IMC_BLOCK_SIZE / 2]);
 

     if (buf_size < IMC_BLOCK_SIZE * avctx->channels) {
         av_log(avctx, AV_LOG_ERROR, "frame too small!\n");

         return AVERROR_INVALIDDATA;

     }
 

     /* get output buffer */

     frame->nb_samples = COEFFS;

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

         return ret;

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

         q->out_samples = (float *)frame->extended_data[i];

 
         q->dsp.bswap16_buf(buf16, (const uint16_t*)buf, IMC_BLOCK_SIZE / 2);
 
         init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
 
         buf += IMC_BLOCK_SIZE;
 
         if ((ret = imc_decode_block(avctx, q, i)) < 0)
             return ret;
     }

     if (avctx->channels == 2) {

         q->fdsp.butterflies_float((float *)frame->extended_data[0],
                                   (float *)frame->extended_data[1], COEFFS);

     }

     *got_frame_ptr = 1;

     return IMC_BLOCK_SIZE * avctx->channels;

 }
 
 

 static av_cold int imc_decode_close(AVCodecContext * avctx)

 {
     IMCContext *q = avctx->priv_data;
 
     ff_fft_end(&q->fft);

     return 0;
 }
 

 static av_cold void flush(AVCodecContext *avctx)
 {
     IMCContext *q = avctx->priv_data;
 
     q->chctx[0].decoder_reset =
     q->chctx[1].decoder_reset = 1;
 }
 

 #if CONFIG_IMC_DECODER

 AVCodec ff_imc_decoder = {

     .name           = "imc",

     .long_name      = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),

     .type           = AVMEDIA_TYPE_AUDIO,

     .id             = AV_CODEC_ID_IMC,

     .priv_data_size = sizeof(IMCContext),

     .init           = imc_decode_init,
     .close          = imc_decode_close,
     .decode         = imc_decode_frame,

     .flush          = flush,

     .capabilities   = CODEC_CAP_DR1,

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

 };

 #endif
 #if CONFIG_IAC_DECODER

 AVCodec ff_iac_decoder = {
     .name           = "iac",

     .long_name      = NULL_IF_CONFIG_SMALL("IAC (Indeo Audio Coder)"),

     .type           = AVMEDIA_TYPE_AUDIO,

     .id             = AV_CODEC_ID_IAC,

     .priv_data_size = sizeof(IMCContext),
     .init           = imc_decode_init,
     .close          = imc_decode_close,
     .decode         = imc_decode_frame,

     .flush          = flush,

     .capabilities   = CODEC_CAP_DR1,

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

 };

 #endif