mirror of
https://github.com/FFmpeg/FFmpeg.git
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1e5dbb3409
This commit attempts to mirror what the decoder does more closely in addition to fixing some shortcomings.
235 lines
8.2 KiB
C
235 lines
8.2 KiB
C
/*
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* AAC encoder long term prediction extension
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* Copyright (C) 2015 Rostislav Pehlivanov
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* AAC encoder long term prediction extension
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* @author Rostislav Pehlivanov ( atomnuker gmail com )
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*/
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#include "aacenc_ltp.h"
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#include "aacenc_quantization.h"
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#include "aacenc_utils.h"
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/**
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* Encode LTP data.
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*/
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void ff_aac_encode_ltp_info(AACEncContext *s, SingleChannelElement *sce,
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int common_window)
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{
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int i;
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IndividualChannelStream *ics = &sce->ics;
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if (s->profile != FF_PROFILE_AAC_LTP || !ics->predictor_present)
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return;
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if (common_window)
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put_bits(&s->pb, 1, 0);
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put_bits(&s->pb, 1, ics->ltp.present);
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if (!ics->ltp.present)
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return;
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put_bits(&s->pb, 11, ics->ltp.lag);
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put_bits(&s->pb, 3, ics->ltp.coef_idx);
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for (i = 0; i < FFMIN(ics->max_sfb, MAX_LTP_LONG_SFB); i++)
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put_bits(&s->pb, 1, ics->ltp.used[i]);
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}
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void ff_aac_ltp_insert_new_frame(AACEncContext *s)
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{
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int i, ch, tag, chans, cur_channel, start_ch = 0;
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ChannelElement *cpe;
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SingleChannelElement *sce;
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for (i = 0; i < s->chan_map[0]; i++) {
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cpe = &s->cpe[i];
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tag = s->chan_map[i+1];
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chans = tag == TYPE_CPE ? 2 : 1;
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for (ch = 0; ch < chans; ch++) {
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sce = &cpe->ch[ch];
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cur_channel = start_ch + ch;
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/* New sample + overlap */
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memcpy(&sce->ltp_state[0], &sce->ltp_state[1024], 1024*sizeof(sce->ltp_state[0]));
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memcpy(&sce->ltp_state[1024], &s->planar_samples[cur_channel][2048], 1024*sizeof(sce->ltp_state[0]));
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memcpy(&sce->ltp_state[2048], &sce->ret_buf[0], 1024*sizeof(sce->ltp_state[0]));
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sce->ics.ltp.lag = 0;
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}
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start_ch += chans;
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}
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}
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static void get_lag(float *buf, const float *new, LongTermPrediction *ltp)
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{
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int i, j, lag, max_corr = 0;
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float max_ratio;
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for (i = 0; i < 2048; i++) {
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float corr, s0 = 0.0f, s1 = 0.0f;
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const int start = FFMAX(0, i - 1024);
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for (j = start; j < 2048; j++) {
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const int idx = j - i + 1024;
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s0 += new[j]*buf[idx];
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s1 += buf[idx]*buf[idx];
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}
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corr = s1 > 0.0f ? s0/sqrt(s1) : 0.0f;
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if (corr > max_corr) {
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max_corr = corr;
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lag = i;
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max_ratio = corr/(2048-start);
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}
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}
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ltp->lag = FFMAX(av_clip_uintp2(lag, 11), 0);
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ltp->coef_idx = quant_array_idx(max_ratio, ltp_coef, 8);
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ltp->coef = ltp_coef[ltp->coef_idx];
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}
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static void generate_samples(float *buf, LongTermPrediction *ltp)
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{
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int i, samples_num = 2048;
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if (!ltp->lag) {
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ltp->present = 0;
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return;
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} else if (ltp->lag < 1024) {
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samples_num = ltp->lag + 1024;
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}
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for (i = 0; i < samples_num; i++)
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buf[i] = ltp->coef*buf[i + 2048 - ltp->lag];
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memset(&buf[i], 0, (2048 - i)*sizeof(float));
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}
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/**
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* Process LTP parameters
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* @see Patent WO2006070265A1
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*/
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void ff_aac_update_ltp(AACEncContext *s, SingleChannelElement *sce)
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{
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float *pred_signal = &sce->ltp_state[0];
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const float *samples = &s->planar_samples[s->cur_channel][1024];
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if (s->profile != FF_PROFILE_AAC_LTP)
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return;
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/* Calculate lag */
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get_lag(pred_signal, samples, &sce->ics.ltp);
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generate_samples(pred_signal, &sce->ics.ltp);
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}
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void ff_aac_adjust_common_ltp(AACEncContext *s, ChannelElement *cpe)
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{
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int sfb, count = 0;
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SingleChannelElement *sce0 = &cpe->ch[0];
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SingleChannelElement *sce1 = &cpe->ch[1];
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if (!cpe->common_window ||
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sce0->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE ||
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sce1->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE)
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return;
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for (sfb = 0; sfb < FFMIN(sce0->ics.max_sfb, MAX_LTP_LONG_SFB); sfb++) {
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int sum = sce0->ics.ltp.used[sfb] + sce1->ics.ltp.used[sfb];
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if (sum != 2) {
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sce0->ics.ltp.used[sfb] = 0;
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} else if (sum == 2) {
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count++;
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}
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}
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sce0->ics.ltp.present = !!count;
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sce0->ics.predictor_present = !!count;
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}
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/**
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* Mark LTP sfb's
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*/
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void ff_aac_search_for_ltp(AACEncContext *s, SingleChannelElement *sce,
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int common_window)
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{
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int w, g, w2, i, start = 0, count = 0;
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int saved_bits = -(15 + FFMIN(sce->ics.max_sfb, MAX_LTP_LONG_SFB));
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float *C34 = &s->scoefs[128*0], *PCD = &s->scoefs[128*1];
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float *PCD34 = &s->scoefs[128*2];
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const int max_ltp = FFMIN(sce->ics.max_sfb, MAX_LTP_LONG_SFB);
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if (sce->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE) {
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if (sce->ics.ltp.lag) {
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memset(&sce->lcoeffs[0], 0.0f, 3072*sizeof(sce->lcoeffs[0]));
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memset(&sce->ics.ltp, 0, sizeof(LongTermPrediction));
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}
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return;
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}
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if (!sce->ics.ltp.lag)
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return;
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for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
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start = 0;
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for (g = 0; g < sce->ics.num_swb; g++) {
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int bits1 = 0, bits2 = 0;
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float dist1 = 0.0f, dist2 = 0.0f;
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if (w*16+g > max_ltp) {
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start += sce->ics.swb_sizes[g];
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continue;
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}
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for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
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int bits_tmp1, bits_tmp2;
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FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
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for (i = 0; i < sce->ics.swb_sizes[g]; i++)
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PCD[i] = sce->coeffs[start+(w+w2)*128+i] - sce->lcoeffs[start+(w+w2)*128+i];
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abs_pow34_v(C34, &sce->coeffs[start+(w+w2)*128], sce->ics.swb_sizes[g]);
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abs_pow34_v(PCD34, PCD, sce->ics.swb_sizes[g]);
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dist1 += quantize_band_cost(s, &sce->coeffs[start+(w+w2)*128], C34, sce->ics.swb_sizes[g],
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sce->sf_idx[(w+w2)*16+g], sce->band_type[(w+w2)*16+g],
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s->lambda/band->threshold, INFINITY, &bits_tmp1, NULL, 0);
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dist2 += quantize_band_cost(s, PCD, PCD34, sce->ics.swb_sizes[g],
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sce->sf_idx[(w+w2)*16+g],
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sce->band_type[(w+w2)*16+g],
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s->lambda/band->threshold, INFINITY, &bits_tmp2, NULL, 0);
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bits1 += bits_tmp1;
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bits2 += bits_tmp2;
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}
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if (dist2 < dist1 && bits2 < bits1) {
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for (w2 = 0; w2 < sce->ics.group_len[w]; w2++)
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for (i = 0; i < sce->ics.swb_sizes[g]; i++)
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sce->coeffs[start+(w+w2)*128+i] -= sce->lcoeffs[start+(w+w2)*128+i];
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sce->ics.ltp.used[w*16+g] = 1;
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saved_bits += bits1 - bits2;
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count++;
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}
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start += sce->ics.swb_sizes[g];
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}
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}
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sce->ics.ltp.present = !!count && (saved_bits >= 0);
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sce->ics.predictor_present = !!sce->ics.ltp.present;
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/* Reset any marked sfbs */
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if (!sce->ics.ltp.present && !!count) {
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for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
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start = 0;
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for (g = 0; g < sce->ics.num_swb; g++) {
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if (sce->ics.ltp.used[w*16+g]) {
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for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
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for (i = 0; i < sce->ics.swb_sizes[g]; i++) {
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sce->coeffs[start+(w+w2)*128+i] += sce->lcoeffs[start+(w+w2)*128+i];
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}
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}
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}
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start += sce->ics.swb_sizes[g];
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}
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}
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}
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}
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