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FFmpeg4/libavcodec/imc.c

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2023-07-02 12:20:28 +00:00
/*
* 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/ffmath.h"
#include "libavutil/float_dsp.h"
#include "libavutil/internal.h"
#include "avcodec.h"
#include "bswapdsp.h"
#include "get_bits.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 coefficients 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 IMCContext {
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;
BswapDSPContext bdsp;
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];
AVCodecContext *avctx;
} 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] = ff_exp10(-1.0 * tb);
q->weights2[i - 1] = ff_exp10(-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_IAC && avctx->sample_rate > 96000) {
av_log(avctx, AV_LOG_ERROR,
"Strange sample rate of %i, file likely corrupt or "
"needing a new table derivation method.\n",
avctx->sample_rate);
return AVERROR_PATCHWELCOME;
}
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_bswapdsp_init(&q->bdsp);
q->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
if (!q->fdsp) {
ff_fft_end(&q->fft);
return AVERROR(ENOMEM);
}
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[pos]);
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(q->avctx, 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 void imc_get_coeffs(AVCodecContext *avctx,
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 (cw_len && (!chctx->bandFlagsBuf[i] || !chctx->skipFlags[j])) {
if (get_bits_count(&q->gb) + cw_len > 512) {
av_log(avctx, AV_LOG_WARNING,
"Potential problem on band %i, coefficient %i"
": cw_len=%i\n", i, j, cw_len);
} else
cw = get_bits(&q->gb, cw_len);
}
chctx->codewords[j] = cw;
}
}
}
}
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 (((int)((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_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 & 0x1)
imc_decode_level_coefficients_raw(q, chctx->levlCoeffBuf,
chctx->flcoeffs1, chctx->flcoeffs2);
else 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));
imc_get_coeffs(avctx, q, chctx);
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 + AV_INPUT_BUFFER_PADDING_SIZE) / 2]);
q->avctx = avctx;
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->bdsp.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);
av_freep(&q->fdsp);
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 = AV_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 = AV_CODEC_CAP_DR1,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_NONE },
};
#endif