171 lines
6.0 KiB
C
171 lines
6.0 KiB
C
/*
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** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
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** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.com
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**
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** This program is free software; you can redistribute it and/or modify
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** it under the terms of the GNU General Public License as published by
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** the Free Software Foundation; either version 2 of the License, or
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** (at your option) any later version.
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**
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** This program is distributed in the hope that it will be useful,
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** but WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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** GNU General Public License for more details.
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**
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** You should have received a copy of the GNU General Public License
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** along with this program; if not, write to the Free Software
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** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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**
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** Any non-GPL usage of this software or parts of this software is strictly
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** forbidden.
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**
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** The "appropriate copyright message" mentioned in section 2c of the GPLv2
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** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com"
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**
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** Commercial non-GPL licensing of this software is possible.
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** For more info contact Nero AG through Mpeg4AAClicense@nero.com.
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**
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** $Id: ssr.c,v 1.19 2007/11/01 12:33:36 menno Exp $
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**/
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#include "common.h"
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#include "structs.h"
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#ifdef SSR_DEC
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#include "syntax.h"
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#include "filtbank.h"
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#include "ssr.h"
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#include "ssr_fb.h"
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void ssr_decode(ssr_info *ssr, fb_info *fb, uint8_t window_sequence,
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uint8_t window_shape, uint8_t window_shape_prev,
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real_t *freq_in, real_t *time_out, real_t *overlap,
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real_t ipqf_buffer[SSR_BANDS][96 / 4],
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real_t *prev_fmd, uint16_t frame_len)
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{
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uint8_t band;
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uint16_t ssr_frame_len = frame_len / SSR_BANDS;
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real_t time_tmp[2048] = {0};
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real_t output[1024] = {0};
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for (band = 0; band < SSR_BANDS; band++) {
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int16_t j;
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/* uneven bands have inverted frequency scale */
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if (band == 1 || band == 3) {
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for (j = 0; j < ssr_frame_len / 2; j++) {
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real_t tmp;
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tmp = freq_in[j + ssr_frame_len * band];
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freq_in[j + ssr_frame_len * band] =
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freq_in[ssr_frame_len - j - 1 + ssr_frame_len * band];
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freq_in[ssr_frame_len - j - 1 + ssr_frame_len * band] = tmp;
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}
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}
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/* non-overlapping inverse filterbank for SSR */
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ssr_ifilter_bank(fb, window_sequence, window_shape, window_shape_prev,
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freq_in + band * ssr_frame_len, time_tmp + band * ssr_frame_len,
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ssr_frame_len);
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/* gain control */
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ssr_gain_control(ssr, time_tmp, output, overlap, prev_fmd,
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band, window_sequence, ssr_frame_len);
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}
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/* inverse pqf to bring subbands together again */
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ssr_ipqf(ssr, output, time_out, ipqf_buffer, frame_len, SSR_BANDS);
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}
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static void ssr_gain_control(ssr_info *ssr, real_t *data, real_t *output,
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real_t *overlap, real_t *prev_fmd, uint8_t band,
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uint8_t window_sequence, uint16_t frame_len)
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{
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uint16_t i;
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real_t gc_function[2 * 1024 / SSR_BANDS];
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if (window_sequence != EIGHT_SHORT_SEQUENCE) {
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ssr_gc_function(ssr, &prev_fmd[band * frame_len * 2],
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gc_function, window_sequence, band, frame_len);
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for (i = 0; i < frame_len * 2; i++) {
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data[band * frame_len * 2 + i] *= gc_function[i];
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}
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for (i = 0; i < frame_len; i++) {
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output[band * frame_len + i] = overlap[band * frame_len + i] +
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data[band * frame_len * 2 + i];
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}
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for (i = 0; i < frame_len; i++) {
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overlap[band * frame_len + i] =
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data[band * frame_len * 2 + frame_len + i];
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}
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} else {
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uint8_t w;
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for (w = 0; w < 8; w++) {
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uint16_t frame_len8 = frame_len / 8;
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uint16_t frame_len16 = frame_len / 16;
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ssr_gc_function(ssr, &prev_fmd[band * frame_len * 2 + w * frame_len * 2 / 8],
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gc_function, window_sequence, frame_len);
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for (i = 0; i < frame_len8 * 2; i++) {
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data[band * frame_len * 2 + w * frame_len8 * 2 + i] *= gc_function[i];
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}
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for (i = 0; i < frame_len8; i++) {
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overlap[band * frame_len + i + 7 * frame_len16 + w * frame_len8] +=
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data[band * frame_len * 2 + 2 * w * frame_len8 + i];
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}
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for (i = 0; i < frame_len8; i++) {
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overlap[band * frame_len + i + 7 * frame_len16 + (w + 1)*frame_len8] =
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data[band * frame_len * 2 + 2 * w * frame_len8 + frame_len8 + i];
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}
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}
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for (i = 0; i < frame_len; i++) {
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output[band * frame_len + i] = overlap[band * frame_len + i];
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}
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for (i = 0; i < frame_len; i++) {
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overlap[band * frame_len + i] = overlap[band * frame_len + i + frame_len];
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}
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}
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}
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static void ssr_gc_function(ssr_info *ssr, real_t *prev_fmd,
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real_t *gc_function, uint8_t window_sequence,
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uint8_t band, uint16_t frame_len)
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{
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uint16_t i;
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uint16_t len_area1, len_area2;
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int32_t aloc[10];
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real_t alev[10];
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switch (window_sequence) {
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case ONLY_LONG_SEQUENCE:
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len_area1 = frame_len / SSR_BANDS;
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len_area2 = 0;
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break;
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case LONG_START_SEQUENCE:
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len_area1 = (frame_len / SSR_BANDS) * 7 / 32;
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len_area2 = (frame_len / SSR_BANDS) / 16;
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break;
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case EIGHT_SHORT_SEQUENCE:
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len_area1 = (frame_len / 8) / SSR_BANDS;
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len_area2 = 0;
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break;
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case LONG_STOP_SEQUENCE:
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len_area1 = (frame_len / SSR_BANDS);
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len_area2 = 0;
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break;
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}
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/* decode bitstream information */
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/* build array M */
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for (i = 0; i < frame_len * 2; i++) {
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gc_function[i] = 1;
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}
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}
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#endif
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