IMC decoder

Originally committed as revision 6839 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 816 insertions, 0 deletions

diff --git a/libavcodec/imc.c b/libavcodec/imc.c
new file mode 100644
index 0000000000..a7045ef3e1
--- /dev/null
+++ b/libavcodec/imc.c
@@ -0,0 +1,816 @@
+/*
+ * 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.c IMC - Intel Music Coder
+ *  A mdct based codec using a 256 points large transform
+ *  divied into 32 bands with some mix of scale factors.
+ *  Only mono is supported.
+ *
+ */
+
+
+#include <math.h>
+#include <stddef.h>
+#include <stdio.h>
+
+#define ALT_BITSTREAM_READER
+#include "avcodec.h"
+#include "bitstream.h"
+#include "dsputil.h"
+
+#include "imcdata.h"
+
+#define IMC_FRAME_ID 0x21
+#define BANDS 32
+#define COEFFS 256
+
+typedef struct {
+    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];
+
+    /** MDCT tables */
+    //@{
+    float mdct_sine_window[COEFFS];
+    float post_cos[COEFFS];
+    float post_sin[COEFFS];
+    float pre_coef1[COEFFS];
+    float pre_coef2[COEFFS];
+    float last_fft_im[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 sqrt_tab[30];
+    GetBitContext gb;
+    VLC huffman_vlc[4][4];
+    float flcf1, flcf2;
+    int decoder_reset;
+    float one_div_log2;
+
+    DSPContext dsp;
+    FFTContext fft;
+    DECLARE_ALIGNED_16(FFTComplex, samples[COEFFS/2]);
+    DECLARE_ALIGNED_16(float, out_samples[COEFFS]);
+} IMCContext;
+
+
+static int imc_decode_init(AVCodecContext * avctx)
+{
+    int i, j;
+    IMCContext *q = avctx->priv_data;
+    double r1, r2;
+
+    q->decoder_reset = 1;
+
+    for(i = 0; i < BANDS; i++)
+        q->old_floor[i] = 1.0;
+
+    /* Build mdct window, a simple sine window normalized with sqrt(2) */
+    for(i = 0; i < COEFFS; i++)
+        q->mdct_sine_window[i] = sin((i + 0.5) / 512.0 * M_PI) * sqrt(2.0);
+    for(i = 0; i < COEFFS/2; i++){
+        q->post_cos[i] = cos(i / 256.0 * M_PI);
+        q->post_sin[i] = 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);
+        }
+
+        q->last_fft_im[i] = 0;
+    }
+    q->flcf1 = log2(10) * 0.05703125;
+    q->flcf2 = log2(10) * 0.25;
+
+    /* 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++) {
+            init_vlc (&q->huffman_vlc[i][j], 9, imc_huffman_sizes[i],
+                     imc_huffman_lens[i][j], 1, 1,
+                     imc_huffman_bits[i][j], 2, 2, 0);
+        }
+    }
+    q->one_div_log2 = 1/log(2);
+
+    ff_fft_init(&q->fft, 7, 1);
+    dsputil_init(&q->dsp, avctx);
+    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 < 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) * imc_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 > 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) * imc_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] = &q->huffman_vlc[s][0];
+    hufftab[1] = &q->huffman_vlc[s][1];
+    hufftab[2] = &q->huffman_vlc[s][2];
+    hufftab[3] = &q->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_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 / pow (2, levlCoeffBuf[0] * q->flcf1);
+    flcoeffs2[0] = log2(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 += q->flcf2 * level;
+            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) * q->flcf2 + flcoeffs2[i];
+        } else {
+            flcoeffs1[i] = old_floor[i];
+        }
+    }
+}
+
+/**
+ * Perform bit allocation depending on bits available
+ */
+static int bit_allocation (IMCContext* q, 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, q->flcoeffs1[i]);
+
+    for(i = 0; i < BANDS-1; i++) {
+        q->flcoeffs4[i] = q->flcoeffs3[i] - log2(q->flcoeffs5[i]);
+    }
+    q->flcoeffs4[BANDS - 1] = limit;
+
+    highest = highest * 0.25;
+
+    for(i = 0; i < BANDS; i++) {
+        indx = -1;
+        if ((band_tab[i+1] - band_tab[i]) == q->bandWidthT[i])
+            indx = 0;
+
+        if ((band_tab[i+1] - band_tab[i]) > q->bandWidthT[i])
+            indx = 1;
+
+        if (((band_tab[i+1] - band_tab[i])/2) >= q->bandWidthT[i])
+            indx = 2;
+
+        if (indx == -1)
+            return -1;
+
+        q->flcoeffs4[i] = q->flcoeffs4[i] + xTab[(indx*2 + (q->flcoeffs1[i] < highest)) * 2 + flag];
+    }
+
+    if (stream_format_code & 0x2) {
+        q->flcoeffs4[0] = limit;
+        q->flcoeffs4[1] = limit;
+        q->flcoeffs4[2] = limit;
+        q->flcoeffs4[3] = limit;
+    }
+
+    for(i = (stream_format_code & 0x2)?4:0; i < BANDS-1; i++) {
+        iacc += q->bandWidthT[i];
+        summa += q->bandWidthT[i] * q->flcoeffs4[i];
+    }
+    q->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 = clip((int)((q->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
+
+            q->bitsBandT[j] = cwlen;
+            summer += q->bandWidthT[j] * cwlen;
+
+            if (cwlen > 0)
+                iacc += q->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++)
+            q->CWlengthT[j] = q->bitsBandT[i];
+    }
+
+    if (freebits > summer) {
+        for(i = 0; i < BANDS; i++) {
+            workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->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 (++(q->bitsBandT[found_indx]) == 6)
+                    workT[found_indx] = -1.e20;
+
+                for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (freebits > summer); j++){
+                    q->CWlengthT[j]++;
+                    summer++;
+                }
+            }
+        }while (freebits > summer);
+    }
+    if (freebits < summer) {
+        for(i = 0; i < BANDS; i++) {
+            workT[i] = q->bitsBandT[i] ? (q->bitsBandT[i] * -2 + q->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 (!(--q->bitsBandT[low_indx]))
+                workT[low_indx] = 1.e20;
+
+            for(j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++){
+                if(q->CWlengthT[j] > 0){
+                    q->CWlengthT[j]--;
+                    summer--;
+                }
+            }
+        }
+    }
+    return 0;
+}
+
+static void imc_get_skip_coeff(IMCContext* q) {
+    int i, j;
+
+    memset(q->skipFlagBits, 0, sizeof(q->skipFlagBits));
+    memset(q->skipFlagCount, 0, sizeof(q->skipFlagCount));
+    for(i = 0; i < BANDS; i++) {
+        if (!q->bandFlagsBuf[i] || !q->bandWidthT[i])
+            continue;
+
+        if (!q->skipFlagRaw[i]) {
+            q->skipFlagBits[i] = band_tab[i+1] - band_tab[i];
+
+            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
+                if ((q->skipFlags[j] = get_bits(&q->gb,1)))
+                    q->skipFlagCount[i]++;
+            }
+        } else {
+            for(j = band_tab[i]; j < (band_tab[i+1]-1); j += 2) {
+                if(!get_bits1(&q->gb)){//0
+                    q->skipFlagBits[i]++;
+                    q->skipFlags[j]=1;
+                    q->skipFlags[j+1]=1;
+                    q->skipFlagCount[i] += 2;
+                }else{
+                    if(get_bits1(&q->gb)){//11
+                        q->skipFlagBits[i] +=2;
+                        q->skipFlags[j]=0;
+                        q->skipFlags[j+1]=1;
+                        q->skipFlagCount[i]++;
+                    }else{
+                        q->skipFlagBits[i] +=3;
+                        q->skipFlags[j+1]=0;
+                        if(!get_bits1(&q->gb)){//100
+                            q->skipFlags[j]=1;
+                            q->skipFlagCount[i]++;
+                        }else{//101
+                            q->skipFlags[j]=0;
+                        }
+                    }
+                }
+            }
+
+            if (j < band_tab[i+1]) {
+                q->skipFlagBits[i]++;
+                if ((q->skipFlags[j] = get_bits(&q->gb,1)))
+                    q->skipFlagCount[i]++;
+            }
+        }
+    }
+}
+
+/**
+ * Increase highest' band coefficient sizes as some bits won't be used
+ */
+static void imc_adjust_bit_allocation (IMCContext* q, 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] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->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 (++(q->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 (!q->skipFlags[j] && (q->CWlengthT[j] < 6)) {
+                    q->CWlengthT[j]++;
+                    corrected++;
+                }
+            }
+        }
+    }
+}
+
+void imc_imdct256(IMCContext *q) {
+    int i;
+    float re, im;
+
+    /* prerotation */
+    for(i=0; i < COEFFS/2; i++){
+        q->samples[i].re = -(q->pre_coef1[i] * q->CWdecoded[COEFFS-1-i*2]) -
+                           (q->pre_coef2[i] * q->CWdecoded[i*2]);
+        q->samples[i].im = (q->pre_coef2[i] * q->CWdecoded[COEFFS-1-i*2]) -
+                           (q->pre_coef1[i] * q->CWdecoded[i*2]);
+    }
+
+    /* FFT */
+    ff_fft_permute(&q->fft, q->samples);
+    ff_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]);
+        q->out_samples[i*2] = (q->mdct_sine_window[COEFFS-1-i*2] * q->last_fft_im[i]) + (q->mdct_sine_window[i*2] * re);
+        q->out_samples[COEFFS-1-i*2] = (q->mdct_sine_window[i*2] * q->last_fft_im[i]) - (q->mdct_sine_window[COEFFS-1-i*2] * re);
+        q->last_fft_im[i] = im;
+    }
+}
+
+static int inverse_quant_coeff (IMCContext* q, 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++) {
+            q->CWdecoded[j] = 0;
+            cw_len = q->CWlengthT[j];
+
+            if (cw_len <= 0 || q->skipFlags[j])
+                continue;
+
+            max_size = 1 << cw_len;
+            middle_value = max_size >> 1;
+
+            if (q->codewords[j] >= max_size || q->codewords[j] < 0)
+                return -1;
+
+            if (cw_len >= 4){
+                quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
+                if (q->codewords[j] >= middle_value)
+                    q->CWdecoded[j] = quantizer[q->codewords[j] - 8] * q->flcoeffs6[i];
+                else
+                    q->CWdecoded[j] = -quantizer[max_size - q->codewords[j] - 8 - 1] * q->flcoeffs6[i];
+            }else{
+                quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (q->bandFlagsBuf[i] << 1)];
+                if (q->codewords[j] >= middle_value)
+                    q->CWdecoded[j] = quantizer[q->codewords[j] - 1] * q->flcoeffs6[i];
+                else
+                    q->CWdecoded[j] = -quantizer[max_size - 2 - q->codewords[j]] * q->flcoeffs6[i];
+            }
+        }
+    }
+    return 0;
+}
+
+
+static int imc_get_coeffs (IMCContext* q) {
+    int i, j, cw_len, cw;
+
+    for(i = 0; i < BANDS; i++) {
+        if(!q->sumLenArr[i]) continue;
+        if (q->bandFlagsBuf[i] || q->bandWidthT[i]) {
+            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
+                cw_len = q->CWlengthT[j];
+                cw = 0;
+
+                if (get_bits_count(&q->gb) + cw_len > 512){
+//av_log(NULL,0,"Band %i coeff %i cw_len %i\n",i,j,cw_len);
+                    return -1;
+                }
+
+                if(cw_len && (!q->bandFlagsBuf[i] || !q->skipFlags[j]))
+                    cw = get_bits(&q->gb, cw_len);
+
+                q->codewords[j] = cw;
+            }
+        }
+    }
+    return 0;
+}
+
+static int imc_decode_frame(AVCodecContext * avctx,
+                            void *data, int *data_size,
+                            uint8_t * buf, int buf_size)
+{
+
+    IMCContext *q = avctx->priv_data;
+
+    int stream_format_code;
+    int imc_hdr, i, j;
+    int flag;
+    int bits, summer;
+    int counter, bitscount;
+    uint16_t *buf16 = (uint16_t *) buf;
+
+    /* FIXME: input should not be modified */
+    for(i = 0; i < FFMIN(buf_size, avctx->block_align) / 2; i++)
+        buf16[i] = bswap_16(buf16[i]);
+
+    init_get_bits(&q->gb, buf, 512);
+
+    /* Check the frame header */
+    imc_hdr = get_bits(&q->gb, 9);
+    if (imc_hdr != IMC_FRAME_ID) {
+        av_log(avctx, AV_LOG_ERROR, "imc frame header check failed!\n");
+        av_log(avctx, AV_LOG_ERROR, "got %x instead of 0x21.\n", imc_hdr);
+        return -1;
+    }
+    stream_format_code = get_bits(&q->gb, 3);
+
+    if(stream_format_code & 1){
+        av_log(avctx, AV_LOG_ERROR, "Stream code format %X is not supported\n", stream_format_code);
+        return -1;
+    }
+
+//    av_log(avctx, AV_LOG_DEBUG, "stream_format_code = %d\n", stream_format_code);
+
+    if (stream_format_code & 0x04)
+        q->decoder_reset = 1;
+
+    if(q->decoder_reset) {
+        memset(q->out_samples, 0, sizeof(q->out_samples));
+        for(i = 0; i < BANDS; i++)q->old_floor[i] = 1.0;
+        for(i = 0; i < COEFFS; i++)q->CWdecoded[i] = 0;
+        q->decoder_reset = 0;
+    }
+
+    flag = get_bits1(&q->gb);
+    imc_read_level_coeffs(q, stream_format_code, q->levlCoeffBuf);
+
+    if (stream_format_code & 0x4)
+        imc_decode_level_coefficients(q, q->levlCoeffBuf, q->flcoeffs1, q->flcoeffs2);
+    else
+        imc_decode_level_coefficients2(q, q->levlCoeffBuf, q->old_floor, q->flcoeffs1, q->flcoeffs2);
+
+    memcpy(q->old_floor, q->flcoeffs1, 32 * sizeof(float));
+
+    counter = 0;
+    for (i=0 ; i<BANDS ; i++) {
+        if (q->levlCoeffBuf[i] == 16) {
+            q->bandWidthT[i] = 0;
+            counter++;
+        } else
+            q->bandWidthT[i] = band_tab[i+1] - band_tab[i];
+    }
+    memset(q->bandFlagsBuf, 0, BANDS * sizeof(int));
+    for(i = 0; i < BANDS-1; i++) {
+        if (q->bandWidthT[i])
+            q->bandFlagsBuf[i] = get_bits1(&q->gb);
+    }
+
+    imc_calculate_coeffs(q, q->flcoeffs1, q->flcoeffs2, q->bandWidthT, q->flcoeffs3, q->flcoeffs5);
+
+    bitscount = 0;
+    /* first 4 bands will be assigned 5 bits per coefficient */
+    if (stream_format_code & 0x2) {
+        bitscount += 15;
+
+        q->bitsBandT[0] = 5;
+        q->CWlengthT[0] = 5;
+        q->CWlengthT[1] = 5;
+        q->CWlengthT[2] = 5;
+        for(i = 1; i < 4; i++){
+            bits = (q->levlCoeffBuf[i] == 16) ? 0 : 5;
+            q->bitsBandT[i] = bits;
+            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
+                q->CWlengthT[j] = bits;
+                bitscount += bits;
+            }
+        }
+    }
+
+    if(bit_allocation (q, stream_format_code, 512 - bitscount - get_bits_count(&q->gb), flag) < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
+        q->decoder_reset = 1;
+        return -1;
+    }
+
+    for(i = 0; i < BANDS; i++) {
+        q->sumLenArr[i] = 0;
+        q->skipFlagRaw[i] = 0;
+        for(j = band_tab[i]; j < band_tab[i+1]; j++)
+            q->sumLenArr[i] += q->CWlengthT[j];
+        if (q->bandFlagsBuf[i])
+            if( (((band_tab[i+1] - band_tab[i]) * 1.5) > q->sumLenArr[i]) && (q->sumLenArr[i] > 0))
+                q->skipFlagRaw[i] = 1;
+    }
+
+    imc_get_skip_coeff(q);
+
+    for(i = 0; i < BANDS; i++) {
+        q->flcoeffs6[i] = q->flcoeffs1[i];
+        /* band has flag set and at least one coded coefficient */
+        if (q->bandFlagsBuf[i] && (band_tab[i+1] - band_tab[i]) != q->skipFlagCount[i]){
+                q->flcoeffs6[i] *= q->sqrt_tab[band_tab[i+1] - band_tab[i]] /
+                                   q->sqrt_tab[(band_tab[i+1] - band_tab[i] - q->skipFlagCount[i])];
+        }
+    }
+
+    /* calculate bits left, bits needed and adjust bit allocation */
+    bits = summer = 0;
+
+    for(i = 0; i < BANDS; i++) {
+        if (q->bandFlagsBuf[i]) {
+            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
+                if(q->skipFlags[j]) {
+                    summer += q->CWlengthT[j];
+                    q->CWlengthT[j] = 0;
+                }
+            }
+            bits += q->skipFlagBits[i];
+            summer -= q->skipFlagBits[i];
+        }
+    }
+    imc_adjust_bit_allocation(q, summer);
+
+    for(i = 0; i < BANDS; i++) {
+        q->sumLenArr[i] = 0;
+
+        for(j = band_tab[i]; j < band_tab[i+1]; j++)
+            if (!q->skipFlags[j])
+                q->sumLenArr[i] += q->CWlengthT[j];
+    }
+
+    memset(q->codewords, 0, sizeof(q->codewords));
+
+    if(imc_get_coeffs(q) < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");
+        q->decoder_reset = 1;
+        return 0;
+    }
+
+    if(inverse_quant_coeff(q, stream_format_code) < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
+        q->decoder_reset = 1;
+        return 0;
+    }
+
+    memset(q->skipFlags, 0, sizeof(q->skipFlags));
+
+    imc_imdct256(q);
+
+    q->dsp.float_to_int16(data, q->out_samples, COEFFS);
+
+    *data_size = COEFFS * sizeof(int16_t);
+
+    return avctx->block_align;
+}
+
+
+static int imc_decode_close(AVCodecContext * avctx)
+{
+    IMCContext *q = avctx->priv_data;
+
+    ff_fft_end(&q->fft);
+    return 0;
+}
+
+
+AVCodec imc_decoder = {
+    .name = "imc",
+    .type = CODEC_TYPE_AUDIO,
+    .id = CODEC_ID_IMC,
+    .priv_data_size = sizeof(IMCContext),
+    .init = imc_decode_init,
+    .close = imc_decode_close,
+    .decode = imc_decode_frame,
+};