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FFmpeg/libavcodec/imc.c

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/*
* 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];
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;
}
/* 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, 1);
}
}
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] * 0.18945); // 0.18945 = log2(10) * 0.05703125
flcoeffs2[0] = log(flcoeffs1[0])/log(2);
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];
}
}
}
/**
* 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] - log(q->flcoeffs5[i])/log(2);
}
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 = av_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_bits1(&q->gb)))
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_bits1(&q->gb)))
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++;
}
}
}
}
}
static 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,
const 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,
};