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52 lines
1.8 KiB
52 lines
1.8 KiB
/* |
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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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