/*
  * AAC encoder TNS
  * 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 temporal noise shaping
  * @author Rostislav Pehlivanov ( atomnuker gmail com )
  */
 
 #ifndef AVCODEC_AACENC_TNS_H
 #define AVCODEC_AACENC_TNS_H
 

 #include "aacenc.h"

 /* Could be set to 3 to save an additional bit at the cost of little quality */
 #define TNS_Q_BITS 4
 
 /* TNS will only be used if the LPC gain is within these margins */
 #define TNS_GAIN_THRESHOLD_LOW  1.395f
 #define TNS_GAIN_THRESHOLD_HIGH 11.19f
 

 /* If the energy ratio between the low SFBs vs the high SFBs is not between
  * those two values, use 2 filters instead */
 #define TNS_E_RATIO_LOW  0.77
 #define TNS_E_RATIO_HIGH 1.23

 /* Do not use TNS if the psy band spread is below this value */
 #define TNS_SPREAD_THRESHOLD 37.081512f

 void ff_aac_encode_tns_info(AACEncContext *s, SingleChannelElement *sce);

 void ff_aac_apply_tns(AACEncContext *s, SingleChannelElement *sce);

 void ff_aac_search_for_tns(AACEncContext *s, SingleChannelElement *sce);

 
 #endif /* AVCODEC_AACENC_TNS_H */