| /* |
| * AAC encoder long term prediction extension |
| * Copyright (C) 2015 Rostislav Pehlivanov |
| * |
| * 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 |
| * AAC encoder long term prediction extension |
| * @author Rostislav Pehlivanov ( atomnuker gmail com ) |
| */ |
| |
| #include "aacenc_ltp.h" |
| #include "aacenc_quantization.h" |
| #include "aacenc_utils.h" |
| |
| /** |
| * Encode LTP data. |
| */ |
| void ff_aac_encode_ltp_info(AACEncContext *s, SingleChannelElement *sce, |
| int common_window) |
| { |
| int i; |
| IndividualChannelStream *ics = &sce->ics; |
| if (s->profile != FF_PROFILE_AAC_LTP || !ics->predictor_present) |
| return; |
| if (common_window) |
| put_bits(&s->pb, 1, 0); |
| put_bits(&s->pb, 1, ics->ltp.present); |
| if (!ics->ltp.present) |
| return; |
| put_bits(&s->pb, 11, ics->ltp.lag); |
| put_bits(&s->pb, 3, ics->ltp.coef_idx); |
| for (i = 0; i < FFMIN(ics->max_sfb, MAX_LTP_LONG_SFB); i++) |
| put_bits(&s->pb, 1, ics->ltp.used[i]); |
| } |
| |
| void ff_aac_ltp_insert_new_frame(AACEncContext *s) |
| { |
| int i, ch, tag, chans, cur_channel, start_ch = 0; |
| ChannelElement *cpe; |
| SingleChannelElement *sce; |
| for (i = 0; i < s->chan_map[0]; i++) { |
| cpe = &s->cpe[i]; |
| tag = s->chan_map[i+1]; |
| chans = tag == TYPE_CPE ? 2 : 1; |
| for (ch = 0; ch < chans; ch++) { |
| sce = &cpe->ch[ch]; |
| cur_channel = start_ch + ch; |
| /* New sample + overlap */ |
| memcpy(&sce->ltp_state[0], &sce->ltp_state[1024], 1024*sizeof(sce->ltp_state[0])); |
| memcpy(&sce->ltp_state[1024], &s->planar_samples[cur_channel][2048], 1024*sizeof(sce->ltp_state[0])); |
| memcpy(&sce->ltp_state[2048], &sce->ret_buf[0], 1024*sizeof(sce->ltp_state[0])); |
| sce->ics.ltp.lag = 0; |
| } |
| start_ch += chans; |
| } |
| } |
| |
| static void get_lag(float *buf, const float *new, LongTermPrediction *ltp) |
| { |
| int i, j, lag = 0, max_corr = 0; |
| float max_ratio = 0.0f; |
| for (i = 0; i < 2048; i++) { |
| float corr, s0 = 0.0f, s1 = 0.0f; |
| const int start = FFMAX(0, i - 1024); |
| for (j = start; j < 2048; j++) { |
| const int idx = j - i + 1024; |
| s0 += new[j]*buf[idx]; |
| s1 += buf[idx]*buf[idx]; |
| } |
| corr = s1 > 0.0f ? s0/sqrt(s1) : 0.0f; |
| if (corr > max_corr) { |
| max_corr = corr; |
| lag = i; |
| max_ratio = corr/(2048-start); |
| } |
| } |
| ltp->lag = FFMAX(av_clip_uintp2(lag, 11), 0); |
| ltp->coef_idx = quant_array_idx(max_ratio, ltp_coef, 8); |
| ltp->coef = ltp_coef[ltp->coef_idx]; |
| } |
| |
| static void generate_samples(float *buf, LongTermPrediction *ltp) |
| { |
| int i, samples_num = 2048; |
| if (!ltp->lag) { |
| ltp->present = 0; |
| return; |
| } else if (ltp->lag < 1024) { |
| samples_num = ltp->lag + 1024; |
| } |
| for (i = 0; i < samples_num; i++) |
| buf[i] = ltp->coef*buf[i + 2048 - ltp->lag]; |
| memset(&buf[i], 0, (2048 - i)*sizeof(float)); |
| } |
| |
| /** |
| * Process LTP parameters |
| * @see Patent WO2006070265A1 |
| */ |
| void ff_aac_update_ltp(AACEncContext *s, SingleChannelElement *sce) |
| { |
| float *pred_signal = &sce->ltp_state[0]; |
| const float *samples = &s->planar_samples[s->cur_channel][1024]; |
| |
| if (s->profile != FF_PROFILE_AAC_LTP) |
| return; |
| |
| /* Calculate lag */ |
| get_lag(pred_signal, samples, &sce->ics.ltp); |
| generate_samples(pred_signal, &sce->ics.ltp); |
| } |
| |
| void ff_aac_adjust_common_ltp(AACEncContext *s, ChannelElement *cpe) |
| { |
| int sfb, count = 0; |
| SingleChannelElement *sce0 = &cpe->ch[0]; |
| SingleChannelElement *sce1 = &cpe->ch[1]; |
| |
| if (!cpe->common_window || |
| sce0->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE || |
| sce1->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE) { |
| sce0->ics.ltp.present = 0; |
| return; |
| } |
| |
| for (sfb = 0; sfb < FFMIN(sce0->ics.max_sfb, MAX_LTP_LONG_SFB); sfb++) { |
| int sum = sce0->ics.ltp.used[sfb] + sce1->ics.ltp.used[sfb]; |
| if (sum != 2) { |
| sce0->ics.ltp.used[sfb] = 0; |
| } else if (sum == 2) { |
| count++; |
| } |
| } |
| |
| sce0->ics.ltp.present = !!count; |
| sce0->ics.predictor_present = !!count; |
| } |
| |
| /** |
| * Mark LTP sfb's |
| */ |
| void ff_aac_search_for_ltp(AACEncContext *s, SingleChannelElement *sce, |
| int common_window) |
| { |
| int w, g, w2, i, start = 0, count = 0; |
| int saved_bits = -(15 + FFMIN(sce->ics.max_sfb, MAX_LTP_LONG_SFB)); |
| float *C34 = &s->scoefs[128*0], *PCD = &s->scoefs[128*1]; |
| float *PCD34 = &s->scoefs[128*2]; |
| const int max_ltp = FFMIN(sce->ics.max_sfb, MAX_LTP_LONG_SFB); |
| |
| if (sce->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE) { |
| if (sce->ics.ltp.lag) { |
| memset(&sce->ltp_state[0], 0, 3072*sizeof(sce->ltp_state[0])); |
| memset(&sce->ics.ltp, 0, sizeof(LongTermPrediction)); |
| } |
| return; |
| } |
| |
| if (!sce->ics.ltp.lag || s->lambda > 120.0f) |
| return; |
| |
| for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) { |
| start = 0; |
| for (g = 0; g < sce->ics.num_swb; g++) { |
| int bits1 = 0, bits2 = 0; |
| float dist1 = 0.0f, dist2 = 0.0f; |
| if (w*16+g > max_ltp) { |
| start += sce->ics.swb_sizes[g]; |
| continue; |
| } |
| for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) { |
| int bits_tmp1, bits_tmp2; |
| FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g]; |
| for (i = 0; i < sce->ics.swb_sizes[g]; i++) |
| PCD[i] = sce->coeffs[start+(w+w2)*128+i] - sce->lcoeffs[start+(w+w2)*128+i]; |
| s->abs_pow34(C34, &sce->coeffs[start+(w+w2)*128], sce->ics.swb_sizes[g]); |
| s->abs_pow34(PCD34, PCD, sce->ics.swb_sizes[g]); |
| dist1 += quantize_band_cost(s, &sce->coeffs[start+(w+w2)*128], C34, sce->ics.swb_sizes[g], |
| sce->sf_idx[(w+w2)*16+g], sce->band_type[(w+w2)*16+g], |
| s->lambda/band->threshold, INFINITY, &bits_tmp1, NULL, 0); |
| dist2 += quantize_band_cost(s, PCD, PCD34, sce->ics.swb_sizes[g], |
| sce->sf_idx[(w+w2)*16+g], |
| sce->band_type[(w+w2)*16+g], |
| s->lambda/band->threshold, INFINITY, &bits_tmp2, NULL, 0); |
| bits1 += bits_tmp1; |
| bits2 += bits_tmp2; |
| } |
| if (dist2 < dist1 && bits2 < bits1) { |
| for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) |
| for (i = 0; i < sce->ics.swb_sizes[g]; i++) |
| sce->coeffs[start+(w+w2)*128+i] -= sce->lcoeffs[start+(w+w2)*128+i]; |
| sce->ics.ltp.used[w*16+g] = 1; |
| saved_bits += bits1 - bits2; |
| count++; |
| } |
| start += sce->ics.swb_sizes[g]; |
| } |
| } |
| |
| sce->ics.ltp.present = !!count && (saved_bits >= 0); |
| sce->ics.predictor_present = !!sce->ics.ltp.present; |
| |
| /* Reset any marked sfbs */ |
| if (!sce->ics.ltp.present && !!count) { |
| for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) { |
| start = 0; |
| for (g = 0; g < sce->ics.num_swb; g++) { |
| if (sce->ics.ltp.used[w*16+g]) { |
| for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) { |
| for (i = 0; i < sce->ics.swb_sizes[g]; i++) { |
| sce->coeffs[start+(w+w2)*128+i] += sce->lcoeffs[start+(w+w2)*128+i]; |
| } |
| } |
| } |
| start += sce->ics.swb_sizes[g]; |
| } |
| } |
| } |
| } |
