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FFmpeg/libavcodec/imc.c
Reinhard Tartler 737eb5976f Merge libavcore into libavutil 
It is pretty hopeless that other considerable projects will adopt
libavutil alone in other projects. Projects that need small footprint
are better off with more specialized libraries such as gnulib or rather
just copy the necessary parts that they need. With this in mind, nobody
is helped by having libavutil and libavcore split. In order to ease
maintenance inside and around FFmpeg and to reduce confusion where to
put common code, avcore's functionality is merged (back) to avutil.

Signed-off-by: Reinhard Tartler <siretart@tauware.de>
2011-02-15 16:18:21 +01:00

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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 - 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 "get_bits.h"
#include "dsputil.h"
#include "fft.h"
#include "libavutil/audioconvert.h"
#include "imcdata.h"
#define IMC_BLOCK_SIZE 64
#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;
int decoder_reset;
float one_div_log2;
DSPContext dsp;
FFTContext fft;
DECLARE_ALIGNED(16, FFTComplex, samples)[COEFFS/2];
float *out_samples;
} 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 av_cold 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) */
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);
}
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++) {
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);
}
}
q->one_div_log2 = 1/log(2);
ff_fft_init(&q->fft, 7, 1);
dsputil_init(&q->dsp, avctx);
avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
avctx->channel_layout = (avctx->channels==2) ? AV_CH_LAYOUT_STEREO : AV_CH_LAYOUT_MONO;
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] = &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_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_clipf(((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,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->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[IMC_BLOCK_SIZE / 2];
if (buf_size < IMC_BLOCK_SIZE) {
av_log(avctx, AV_LOG_ERROR, "imc frame too small!\n");
return -1;
}
for(i = 0; i < IMC_BLOCK_SIZE / 2; i++)
buf16[i] = av_bswap16(((const uint16_t*)buf)[i]);
q->out_samples = data;
init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
/* 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);
*data_size = COEFFS * sizeof(float);
return IMC_BLOCK_SIZE;
}
static av_cold int imc_decode_close(AVCodecContext * avctx)
{
IMCContext *q = avctx->priv_data;
ff_fft_end(&q->fft);
return 0;
}
AVCodec ff_imc_decoder = {
.name = "imc",
.type = AVMEDIA_TYPE_AUDIO,
.id = CODEC_ID_IMC,
.priv_data_size = sizeof(IMCContext),
.init = imc_decode_init,
.close = imc_decode_close,
.decode = imc_decode_frame,
.long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),
};
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