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af_hdcd: Code comments update
Signed-off-by: Burt P <pburt0@gmail.com>
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Burt P
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@ -1,40 +1,46 @@
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/*
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Copyright (C) 2010, Chris Moeller,
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All rights reserved.
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Optimizations by Gumboot
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Redistribution and use in source and binary forms, with or without modification,
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are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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3. The names of its contributors may not be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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* Copyright (C) 2010, Chris Moeller,
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* All rights reserved.
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* Optimizations by Gumboot
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* Additional work by Burt P.
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* Original code reverse engineered from HDCD decoder library by Christopher Key,
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* which was likely reverse engineered from Windows Media Player.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The names of its contributors may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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Original code reverse engineered from HDCD decoder library by Christopher Key,
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which was likely reverse engineered from Windows Media Player.
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* HDCD is High Definition Compatible Digital
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* http://wiki.hydrogenaud.io/index.php?title=High_Definition_Compatible_Digital
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*
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* More information about HDCD-encoded audio CDs:
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* http://www.audiomisc.co.uk/HFN/HDCD/Enigma.html
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* http://www.audiomisc.co.uk/HFN/HDCD/Examined.html
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*/
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/*
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HDCD is High Definition Compatible Digital
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More information about HDCD-encoded audio CDs:
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http://www.audiomisc.co.uk/HFN/HDCD/Enigma.html
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http://www.audiomisc.co.uk/HFN/HDCD/Examined.html
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/**
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* @file
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* HDCD decoding filter
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*/
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#include "libavutil/opt.h"
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@ -820,33 +826,33 @@ typedef struct {
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uint64_t window;
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unsigned char readahead;
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/* arg is set when a packet prefix is found.
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/** arg is set when a packet prefix is found.
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* control is the active control code, where
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* bit 0-3: target_gain, 4-bit (3.1) fixed-point value
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* bit 4 : peak_extend
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* bit 5 : transient_filter
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* bit 6,7: always zero */
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unsigned char arg, control;
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unsigned sustain, sustain_reset; /* code detect timer */
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uint8_t arg, control;
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unsigned int sustain, sustain_reset; /**< code detect timer */
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int running_gain; /* 11-bit (3.8) fixed point, extended from target_gain */
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int running_gain; /**< 11-bit (3.8) fixed point, extended from target_gain */
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/* counters */
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int code_counterA; /* 8-bit format packet */
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int code_counterA_almost; /* looks like an A code, but a bit expected to be 0 is 1 */
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int code_counterB; /* 16-bit format packet, 8-bit code, 8-bit XOR of code */
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int code_counterB_checkfails; /* looks like a B code, but doesn't pass the XOR check */
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int code_counterC; /* packet prefix was found, expect a code */
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int code_counterC_unmatched; /* told to look for a code, but didn't find one */
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int count_peak_extend; /* valid packets where peak_extend was enabled */
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int count_transient_filter; /* valid packets where filter was detected */
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/* target_gain is a 4-bit (3.1) fixed-point value, always
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int code_counterA; /**< 8-bit format packet */
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int code_counterA_almost; /**< looks like an A code, but a bit expected to be 0 is 1 */
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int code_counterB; /**< 16-bit format packet, 8-bit code, 8-bit XOR of code */
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int code_counterB_checkfails; /**< looks like a B code, but doesn't pass the XOR check */
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int code_counterC; /**< packet prefix was found, expect a code */
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int code_counterC_unmatched; /**< told to look for a code, but didn't find one */
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int count_peak_extend; /**< valid packets where peak_extend was enabled */
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int count_transient_filter; /**< valid packets where filter was detected */
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/** target_gain is a 4-bit (3.1) fixed-point value, always
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* negative, but stored positive.
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* The 16 possible values range from -7.5 to 0.0 dB in
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* steps of 0.5, but no value below -6.0 dB should appear. */
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int gain_counts[16]; /* for cursiosity, mostly */
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int gain_counts[16];
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int max_gain;
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/* occurences of code detect timer expiring without detecting
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/** occurences of code detect timer expiring without detecting
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* a code. -1 for timer never set. */
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int count_sustain_expired;
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} hdcd_state_t;
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@ -866,7 +872,7 @@ static const char * const pe_str[] = {
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#define HDCD_PROCESS_STEREO_DEFAULT 1
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#define HDCD_MAX_CHANNELS 2
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/* convert to float from 4-bit (3.1) fixed-point
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/** convert to float from 4-bit (3.1) fixed-point
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* the always-negative value is stored positive, so make it negative */
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#define GAINTOFLOAT(g) (g) ? -(float)(g>>1) - ((g & 1) ? 0.5 : 0.0) : 0.0
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@ -894,38 +900,40 @@ typedef struct HDCDContext {
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const AVClass *class;
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hdcd_state_t state[HDCD_MAX_CHANNELS];
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/* use hdcd_*_stereo() functions to process both channels together.
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/* AVOption members */
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/** use hdcd_*_stereo() functions to process both channels together.
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* -af hdcd=process_stereo=0 for off
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* -af hdcd=process_stereo=1 for on
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* default is HDCD_PROCESS_STEREO_DEFAULT */
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int process_stereo;
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/* always extend peaks above -3dBFS even if PE isn't signaled
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/** always extend peaks above -3dBFS even if PE isn't signaled
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* -af hdcd=force_pe=0 for off
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* -af hdcd=force_pe=1 for on
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* default is off */
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int force_pe;
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/* analyze mode replaces the audio with a solid tone and adjusts
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/** analyze mode replaces the audio with a solid tone and adjusts
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* the amplitude to signal some specific aspect of the decoding
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* process. See docs or HDCD_ANA_* defines. */
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int analyze_mode;
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int ana_snb; /* used in tone generation */
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int ana_snb; /**< used in tone generation */
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/* end AVOption members */
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/* config_input() and config_output() scan links for any resampling
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/** config_input() and config_output() scan links for any resampling
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* or format changes. If found, warnings are issued and bad_config
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* is set. */
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int bad_config;
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AVFilterContext *fctx; /* filter context for logging errors */
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int sample_count; /* used in error logging */
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int val_target_gain; /* last matching target_gain in both channels */
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AVFilterContext *fctx; /**< filter context for logging errors */
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int sample_count; /**< used in error logging */
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int val_target_gain; /**< last matching target_gain in both channels */
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/* User information/stats */
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int hdcd_detected;
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int det_errors; /* detectable errors */
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hdcd_pe_t peak_extend;
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int uses_transient_filter; /* detected, but not implemented */
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float max_gain_adjustment; /* in dB, expected in the range -6.0 to 0.0 */
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int hdcd_detected; /**< Valid HDCD coding was detected */
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int det_errors; /**< detectable errors */
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hdcd_pe_t peak_extend; /**< peak exted used */
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int uses_transient_filter; /**< transient filter flag detected */
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float max_gain_adjustment; /**< in dB, expected in the range -7.5 to 0.0 */
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} HDCDContext;
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#define OFFSET(x) offsetof(HDCDContext, x)
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@ -976,7 +984,7 @@ static void hdcd_reset(hdcd_state_t *state, unsigned rate)
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state->count_sustain_expired = -1;
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}
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/* update the user info/counters */
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/** update the user info/counters */
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static void hdcd_update_info(hdcd_state_t *state)
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{
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if (state->control & 16) state->count_peak_extend++;
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@ -1242,7 +1250,7 @@ static int hdcd_scan_stereo(HDCDContext *ctx, const int32_t *samples, int max)
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return result;
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}
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/* encode a value in the given sample by adjusting the amplitude */
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/** encode a value in the given sample by adjusting the amplitude */
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static int32_t hdcd_analyze_gen(int32_t sample, unsigned int v, unsigned int maxv)
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{
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float sflt = sample, vv = v;
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@ -1252,7 +1260,7 @@ static int32_t hdcd_analyze_gen(int32_t sample, unsigned int v, unsigned int max
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return (int32_t)sflt;
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}
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/* behaves like hdcd_envelope(), but encodes processing information in
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/** behaves like hdcd_envelope(), but encodes processing information in
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* a way that is audible (and visible in an audio editor) to aid analysis. */
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static int hdcd_analyze(int32_t *samples, int count, int stride, int gain, int target_gain, int extend, int mode, int cdt_active, int tg_mismatch)
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{
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@ -1313,6 +1321,7 @@ static int hdcd_analyze(int32_t *samples, int count, int stride, int gain, int t
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return gain;
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}
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/** apply HDCD decoding parameters to a series of samples */
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static int hdcd_envelope(int32_t *samples, int count, int stride, int gain, int target_gain, int extend)
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{
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int i;
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@ -1372,7 +1381,7 @@ static int hdcd_envelope(int32_t *samples, int count, int stride, int gain, int
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return gain;
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}
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/* extract fields from control code */
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/** extract fields from control code */
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static void hdcd_control(HDCDContext *ctx, hdcd_state_t *state, int *peak_extend, int *target_gain)
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{
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*peak_extend = (ctx->force_pe || state->control & 16);
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@ -1500,7 +1509,7 @@ static void hdcd_process_stereo(HDCDContext *ctx, int32_t *samples, int count)
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ctx->state[1].running_gain = gain[1];
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}
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/* tone generator: sample_number, frequency, sample_rate, amplitude */
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/** tone generator: sample_number, frequency, sample_rate, amplitude */
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#define TONEGEN16(sn, f, sr, a) (int16_t)(sin((6.28318530718 * (sn) * (f)) /(sr)) * (a) * 0x7fff)
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static int filter_frame(AVFilterLink *inlink, AVFrame *in)
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