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3381d92671
Since TNS was fixed with the recent commits retweak the values so it's more frequently used. Still not enabled by default yet, though it's possible that it will be made enabled by default in the near future. Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
56 lines
1.8 KiB
C
56 lines
1.8 KiB
C
/*
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* AAC encoder TNS
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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 temporal noise shaping
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* @author Rostislav Pehlivanov ( atomnuker gmail com )
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*/
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#ifndef AVCODEC_AACENC_TNS_H
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#define AVCODEC_AACENC_TNS_H
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#include "aacenc.h"
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/* Could be set to 3 to save an additional bit at the cost of little quality */
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#define TNS_Q_BITS 4
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/* Coefficient resolution in short windows */
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#define TNS_Q_BITS_SHORT 3
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/* TNS will only be used if the LPC gain is within these margins */
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#define TNS_GAIN_THRESHOLD_LOW 1.437f
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#define TNS_GAIN_THRESHOLD_HIGH 21.19f
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/* If the energy ratio between the low SFBs vs the high SFBs is not between
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* those two values, use 2 filters instead */
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#define TNS_E_RATIO_LOW 0.77
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#define TNS_E_RATIO_HIGH 1.23
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/* Do not use TNS if the psy band spread is below this value */
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#define TNS_SPREAD_THRESHOLD 0.5f
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void ff_aac_encode_tns_info(AACEncContext *s, SingleChannelElement *sce);
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void ff_aac_apply_tns(AACEncContext *s, SingleChannelElement *sce);
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void ff_aac_search_for_tns(AACEncContext *s, SingleChannelElement *sce);
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#endif /* AVCODEC_AACENC_TNS_H */
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