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/*
* ATRAC3+ compatible decoder
*
* Copyright (c) 2010-2013 Maxim Poliakovski
*
* 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
* DSP functions for ATRAC3+ decoder.
*/
#define _USE_MATH_DEFINES
#include <math.h>
#include <string.h>
#include "atrac3plus.h"
#define TWOPI (2 * M_PI)
#define DEQUANT_PHASE(ph) (((ph) & 0x1F) << 6)
static float sine_table[2048]; ///< wave table
static float hann_window[256]; ///< Hann windowing function
static float amp_sf_tab[64]; ///< scalefactors for quantized amplitudes
static void vector_fmul(float *dst, const float *src0, const float *src1,
int len)
{
int i;
for (i = 0; i < len; i++)
dst[i] = src0[i] * src1[i];
}
void ff_atrac3p_init_dsp_static(void)
{
int i;
/* generate sine wave table */
for (i = 0; i < 2048; i++)
sine_table[i] = sin(TWOPI * i / 2048);
/* generate Hann window */
for (i = 0; i < 256; i++)
hann_window[i] = (1.0f - cos(TWOPI * i / 256.0f)) * 0.5f;
/* generate amplitude scalefactors table */
for (i = 0; i < 64; i++)
amp_sf_tab[i] = exp2f((i - 3) / 4.0f);
}
/**
* Synthesize sine waves according to given parameters.
*
* @param[in] synth_param ptr to common synthesis parameters
* @param[in] waves_info parameters for each sine wave
* @param[in] envelope envelope data for all waves in a group
* @param[in] invert_phase flag indicating 180° phase shift
* @param[in] reg_offset region offset for trimming envelope data
* @param[out] out receives sythesized data
*/
static void waves_synth(Atrac3pWaveSynthParams *synth_param,
Atrac3pWavesData *waves_info,
Atrac3pWaveEnvelope *envelope,
int invert_phase, int reg_offset, float *out)
{
int i, wn, inc, pos;
double amp;
Atrac3pWaveParam *wave_param = &synth_param->waves[waves_info->start_index];
for (wn = 0; wn < waves_info->num_wavs; wn++, wave_param++) {
/* amplitude dequantization */
amp = amp_sf_tab[wave_param->amp_sf] *
(!synth_param->amplitude_mode
? (wave_param->amp_index + 1) / 15.13f
: 1.0f);
inc = wave_param->freq_index;
pos = DEQUANT_PHASE(wave_param->phase_index) - (reg_offset ^ 128) * inc & 2047;
/* waveform generation */
for (i = 0; i < 128; i++) {
out[i] += sine_table[pos] * amp;
pos = (pos + inc) & 2047;
}
}
/* invert phase if requested */
if (invert_phase)
for (i = 0; i < 128; i++)
out[i] *= -1.0f;
/* fade in with steep Hann window if requested */
if (envelope->has_start_point) {
pos = (envelope->start_pos << 2) - reg_offset;
if (pos > 0 && pos <= 128) {
memset(out, 0, pos * sizeof(*out));
if (!envelope->has_stop_point ||
envelope->start_pos != envelope->stop_pos) {
out[pos + 0] *= hann_window[0];
out[pos + 1] *= hann_window[32];
out[pos + 2] *= hann_window[64];
out[pos + 3] *= hann_window[96];
}
}
}
/* fade out with steep Hann window if requested */
if (envelope->has_stop_point) {
pos = ((envelope->stop_pos + 1) << 2) - reg_offset;
if (pos > 0 && pos <= 128) {
out[pos - 4] *= hann_window[96];
out[pos - 3] *= hann_window[64];
out[pos - 2] *= hann_window[32];
out[pos - 1] *= hann_window[0];
memset(&out[pos], 0, (128 - pos) * sizeof(out[pos]));
}
}
}
void ff_atrac3p_generate_tones(Atrac3pChanUnitCtx *ch_unit,
int ch_num, int sb, float *out)
{
float wavreg1[128] = { 0 };
float wavreg2[128] = { 0 };
int i, reg1_env_nonzero, reg2_env_nonzero;
Atrac3pWavesData *tones_now = &ch_unit->channels[ch_num].tones_info_prev[sb];
Atrac3pWavesData *tones_next = &ch_unit->channels[ch_num].tones_info[sb];
/* reconstruct full envelopes for both overlapping regions
* from truncated bitstream data */
if (tones_next->pend_env.has_start_point &&
tones_next->pend_env.start_pos < tones_next->pend_env.stop_pos) {
tones_next->curr_env.has_start_point = 1;
tones_next->curr_env.start_pos = tones_next->pend_env.start_pos + 32;
} else if (tones_now->pend_env.has_start_point) {
tones_next->curr_env.has_start_point = 1;
tones_next->curr_env.start_pos = tones_now->pend_env.start_pos;
} else {
tones_next->curr_env.has_start_point = 0;
tones_next->curr_env.start_pos = 0;
}
if (tones_now->pend_env.has_stop_point &&
tones_now->pend_env.stop_pos >= tones_next->curr_env.start_pos) {
tones_next->curr_env.has_stop_point = 1;
tones_next->curr_env.stop_pos = tones_now->pend_env.stop_pos;
} else if (tones_next->pend_env.has_stop_point) {
tones_next->curr_env.has_stop_point = 1;
tones_next->curr_env.stop_pos = tones_next->pend_env.stop_pos + 32;
} else {
tones_next->curr_env.has_stop_point = 0;
tones_next->curr_env.stop_pos = 64;
}
/* is the visible part of the envelope non-zero? */
reg1_env_nonzero = (tones_now->curr_env.stop_pos < 32) ? 0 : 1;
reg2_env_nonzero = (tones_next->curr_env.start_pos >= 32) ? 0 : 1;
/* synthesize waves for both overlapping regions */
if (tones_now->num_wavs && reg1_env_nonzero) {
waves_synth(ch_unit->waves_info_prev, tones_now, &tones_now->curr_env,
ch_unit->waves_info_prev->invert_phase[sb] & ch_num,
128, wavreg1);
}
if (tones_next->num_wavs && reg2_env_nonzero) {
waves_synth(ch_unit->waves_info, tones_next, &tones_next->curr_env,
ch_unit->waves_info->invert_phase[sb] & ch_num, 0, wavreg2);
}
/* Hann windowing for non-faded wave signals */
if (tones_now->num_wavs && tones_next->num_wavs &&
reg1_env_nonzero && reg2_env_nonzero) {
vector_fmul(wavreg1, wavreg1, &hann_window[128], 128);
vector_fmul(wavreg2, wavreg2, hann_window, 128);
} else {
if (tones_now->num_wavs && !tones_now->curr_env.has_stop_point)
vector_fmul(wavreg1, wavreg1, &hann_window[128], 128);
if (tones_next->num_wavs && !tones_next->curr_env.has_start_point)
vector_fmul(wavreg2, wavreg2, hann_window, 128);
}
/* Overlap and subtract to get residual */
for (i = 0; i < 128; i++) {
out[i] -= wavreg1[i] + wavreg2[i];
}
}
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