ref: 6c93b4fdda100e449e25d57102a44d9bb63318b0
dir: /libfaad/sbr_dec.c/
/*
** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
** Copyright (C) 2003 M. Bakker, Ahead Software AG, http://www.nero.com
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program 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 General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
** Any non-GPL usage of this software or parts of this software is strictly
** forbidden.
**
** Commercial non-GPL licensing of this software is possible.
** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
**
** $Id: sbr_dec.c,v 1.5 2003/07/29 08:20:13 menno Exp $
**/
/*
SBR Decoder overview:
To achieve a synchronized output signal, the following steps have to be
acknowledged in the decoder:
- The bitstream parser divides the bitstream into two parts; the AAC
core coder part and the SBR part.
- The SBR bitstream part is fed to the bitstream de-multiplexer followed
by de-quantization The raw data is Huffman decoded.
- The AAC bitstream part is fed to the AAC core decoder, where the
bitstream data of the current frame is decoded, yielding a time domain
audio signal block of 1024 samples. The block length could easily be
adapted to other sizes e.g. 960.
- The core coder audio block is fed to the analysis QMF bank using a
delay of 1312 samples.
- The analysis QMF bank performs the filtering of the delayed core coder
audio signal. The output from the filtering is stored in the matrix
Xlow. The output from the analysis QMF bank is delayed tHFGen subband
samples, before being fed to the synthesis QMF bank. To achieve
synchronization tHFGen = 32, i.e. the value must equal the number of
subband samples corresponding to one frame.
- The HF generator calculates XHigh given the matrix XLow. The process
is guided by the SBR data contained in the current frame.
- The envelope adjuster calculates the matrix Y given the matrix XHigh
and the SBR envelope data, extracted from the SBR bitstream. To
achieve synchronization, tHFAdj has to be set to tHFAdj = 0, i.e. the
envelope adjuster operates on data delayed tHFGen subband samples.
- The synthesis QMF bank operates on the delayed output from the analysis
QMF bank and the output from the envelope adjuster.
*/
#include "common.h"
#include "structs.h"
#ifdef SBR_DEC
#include <stdlib.h>
#include "syntax.h"
#include "bits.h"
#include "sbr_syntax.h"
#include "sbr_qmf.h"
#include "sbr_hfgen.h"
#include "sbr_hfadj.h"
sbr_info *sbrDecodeInit()
{
sbr_info *sbr = malloc(sizeof(sbr_info));
memset(sbr, 0, sizeof(sbr_info));
sbr->bs_freq_scale = 2;
sbr->bs_alter_scale = 1;
sbr->bs_noise_bands = 2;
sbr->bs_limiter_bands = 2;
sbr->bs_limiter_gains = 2;
sbr->bs_interpol_freq = 1;
sbr->bs_smoothing_mode = 1;
sbr->bs_start_freq = 5;
sbr->bs_amp_res = 1;
sbr->bs_samplerate_mode = 1;
sbr->prevEnvIsShort[0] = -1;
sbr->prevEnvIsShort[1] = -1;
sbr->header_count = 0;
return sbr;
}
void sbrDecodeEnd(sbr_info *sbr)
{
uint8_t j;
if (sbr)
{
qmfa_end(sbr->qmfa[0]);
qmfs_end(sbr->qmfs[0]);
if (sbr->id_aac == ID_CPE)
{
qmfa_end(sbr->qmfa[1]);
qmfs_end(sbr->qmfs[1]);
}
if (sbr->Xcodec[0]) free(sbr->Xcodec[0]);
if (sbr->Xsbr[0]) free(sbr->Xsbr[0]);
if (sbr->Xcodec[1]) free(sbr->Xcodec[1]);
if (sbr->Xsbr[1]) free(sbr->Xsbr[1]);
for (j = 0; j < 5; j++)
{
if (sbr->G_temp_prev[0][j]) free(sbr->G_temp_prev[0][j]);
if (sbr->Q_temp_prev[0][j]) free(sbr->Q_temp_prev[0][j]);
if (sbr->G_temp_prev[1][j]) free(sbr->G_temp_prev[1][j]);
if (sbr->Q_temp_prev[1][j]) free(sbr->Q_temp_prev[1][j]);
}
free(sbr);
}
}
void sbr_save_prev_data(sbr_info *sbr, uint8_t ch)
{
uint8_t i;
/* save data for next frame */
sbr->kx_prev = sbr->kx;
sbr->L_E_prev[ch] = sbr->L_E[ch];
sbr->f_prev[ch] = sbr->f[ch][sbr->L_E[ch] - 1];
for (i = 0; i < 64; i++)
{
sbr->E_prev[ch][i] = sbr->E[ch][i][sbr->L_E[ch] - 1];
sbr->Q_prev[ch][i] = sbr->Q[ch][i][sbr->L_Q[ch] - 1];
}
for (i = 0; i < 64; i++)
{
sbr->bs_add_harmonic_prev[ch][i] = sbr->bs_add_harmonic[ch][i];
}
sbr->bs_add_harmonic_flag_prev[ch] = sbr->bs_add_harmonic_flag[ch];
if (sbr->l_A[ch] == sbr->L_E[ch])
sbr->prevEnvIsShort[ch] = 0;
else
sbr->prevEnvIsShort[ch] = -1;
}
void sbrDecodeFrame(sbr_info *sbr, real_t *left_channel,
real_t *right_channel, uint8_t id_aac,
uint8_t just_seeked)
{
int16_t i, k, l;
uint8_t dont_process = 0;
uint8_t ch, channels, ret;
real_t *ch_buf;
qmf_t X[32*64];
#ifdef SBR_LOW_POWER
real_t deg[64];
#endif
bitfile *ld = (bitfile*)malloc(sizeof(bitfile));
sbr->id_aac = id_aac;
channels = (id_aac == ID_SCE) ? 1 : 2;
/* initialise and read the bitstream */
faad_initbits(ld, sbr->data, sbr->data_size);
ret = sbr_extension_data(ld, sbr, id_aac);
if (sbr->data) free(sbr->data);
sbr->data = NULL;
ret = ld->error ? ld->error : ret;
faad_endbits(ld);
if (ld) free(ld);
ld = NULL;
if (ret || (sbr->header_count == 0))
{
/* don't process just upsample */
dont_process = 1;
}
if (just_seeked)
sbr->just_seeked = 1;
else
sbr->just_seeked = 0;
for (ch = 0; ch < channels; ch++)
{
if (sbr->frame == 0)
{
uint8_t j;
sbr->qmfa[ch] = qmfa_init(32);
sbr->qmfs[ch] = qmfs_init(64);
for (j = 0; j < 5; j++)
{
sbr->G_temp_prev[ch][j] = malloc(64*sizeof(real_t));
sbr->Q_temp_prev[ch][j] = malloc(64*sizeof(real_t));
}
sbr->Xsbr[ch] = malloc((32+tHFGen)*64 * sizeof(qmf_t));
sbr->Xcodec[ch] = malloc((32+tHFGen)*32 * sizeof(qmf_t));
memset(sbr->Xsbr[ch], 0, (32+tHFGen)*64 * sizeof(qmf_t));
memset(sbr->Xcodec[ch], 0, (32+tHFGen)*32 * sizeof(qmf_t));
}
if (ch == 0)
ch_buf = left_channel;
else
ch_buf = right_channel;
for (i = 0; i < tHFAdj; i++)
{
int8_t j;
for (j = sbr->kx_prev; j < sbr->kx; j++)
{
QMF_RE(sbr->Xcodec[ch][i*32 + j]) = 0;
#ifndef SBR_LOW_POWER
QMF_IM(sbr->Xcodec[ch][i*32 + j]) = 0;
#endif
}
}
/* subband analysis */
sbr_qmf_analysis_32(sbr->qmfa[ch], ch_buf, sbr->Xcodec[ch], tHFGen);
if (!dont_process)
{
/* insert high frequencies here */
/* hf generation using patching */
hf_generation(sbr, sbr->Xcodec[ch], sbr->Xsbr[ch]
#ifdef SBR_LOW_POWER
,deg
#endif
,ch);
#ifdef SBR_LOW_POWER
for (l = sbr->t_E[ch][0]; l < sbr->t_E[ch][sbr->L_E[ch]]; l++)
{
for (k = 0; k < sbr->kx; k++)
{
QMF_RE(sbr->Xsbr[ch][(tHFAdj + l)*64 + k]) = 0;
}
}
#endif
/* hf adjustment */
hf_adjustment(sbr, sbr->Xsbr[ch]
#ifdef SBR_LOW_POWER
,deg
#endif
,ch);
}
if ((sbr->just_seeked != 0) || dont_process)
{
for (l = 0; l < 32; l++)
{
for (k = 0; k < 32; k++)
{
QMF_RE(X[l * 64 + k]) = QMF_RE(sbr->Xcodec[ch][(l + tHFAdj)*32 + k]);
#ifndef SBR_LOW_POWER
QMF_IM(X[l * 64 + k]) = QMF_IM(sbr->Xcodec[ch][(l + tHFAdj)*32 + k]);
#endif
}
for (k = 32; k < 64; k++)
{
QMF_RE(X[l * 64 + k]) = 0;
#ifndef SBR_LOW_POWER
QMF_IM(X[l * 64 + k]) = 0;
#endif
}
}
} else {
for (l = 0; l < 32; l++)
{
uint8_t xover_band;
if (l < sbr->t_E[ch][0])
xover_band = sbr->kx_prev;
else
xover_band = sbr->kx;
for (k = 0; k < xover_band; k++)
{
QMF_RE(X[l * 64 + k]) = QMF_RE(sbr->Xcodec[ch][(l + tHFAdj)*32 + k]);
#ifndef SBR_LOW_POWER
QMF_IM(X[l * 64 + k]) = QMF_IM(sbr->Xcodec[ch][(l + tHFAdj)*32 + k]);
#endif
}
for (k = xover_band; k < 64; k++)
{
QMF_RE(X[l * 64 + k]) = QMF_RE(sbr->Xsbr[ch][(l + tHFAdj)*64 + k]);
#ifndef SBR_LOW_POWER
QMF_IM(X[l * 64 + k]) = QMF_IM(sbr->Xsbr[ch][(l + tHFAdj)*64 + k]);
#endif
}
#ifdef SBR_LOW_POWER
QMF_RE(X[l * 64 + xover_band - 1]) += QMF_RE(sbr->Xsbr[ch][(l + tHFAdj)*64 + xover_band - 1]);
#endif
}
}
/* subband synthesis */
sbr_qmf_synthesis_64(sbr->qmfs[ch], (const complex_t*)X, ch_buf);
for (i = 0; i < 32; i++)
{
int8_t j;
for (j = 0; j < tHFGen; j++)
{
QMF_RE(sbr->Xcodec[ch][j*32 + i]) = QMF_RE(sbr->Xcodec[ch][(j+32)*32 + i]);
#ifndef SBR_LOW_POWER
QMF_IM(sbr->Xcodec[ch][j*32 + i]) = QMF_IM(sbr->Xcodec[ch][(j+32)*32 + i]);
#endif
}
}
for (i = 0; i < 64; i++)
{
int8_t j;
for (j = 0; j < tHFGen; j++)
{
QMF_RE(sbr->Xsbr[ch][j*64 + i]) = QMF_RE(sbr->Xsbr[ch][(j+32)*64 + i]);
#ifndef SBR_LOW_POWER
QMF_IM(sbr->Xsbr[ch][j*64 + i]) = QMF_IM(sbr->Xsbr[ch][(j+32)*64 + i]);
#endif
}
}
}
if (sbr->bs_header_flag)
sbr->just_seeked = 0;
if (sbr->header_count != 0)
{
for (ch = 0; ch < channels; ch++)
sbr_save_prev_data(sbr, ch);
}
sbr->frame++;
}
#endif