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authorKostya Shishkov <kostya.shishkov@gmail.com>2006-10-30 13:48:48 +0000
committerKostya Shishkov <kostya.shishkov@gmail.com>2006-10-30 13:48:48 +0000
commit84ed36da85b65b3b135f4dc06589454190fd4572 (patch)
tree9a2dff40ca468d150e4dcc115aa6733232183198 /libavcodec/imc.c
parent9c5d7c568b882f78f1b5c84a3b8e7c44a527054d (diff)
IMC decoder
Originally committed as revision 6839 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/imc.c')
-rw-r--r--libavcodec/imc.c816
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,
+};