forked from KolibriOS/kolibrios
53 lines
1.8 KiB
C
53 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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/* TNS will only be used if the LPC gain is within these margins */
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#define TNS_GAIN_THRESHOLD_LOW 1.395f
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#define TNS_GAIN_THRESHOLD_HIGH 11.19f
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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 37.081512f
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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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