126 lines
4.9 KiB
C
126 lines
4.9 KiB
C
/*
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Copyright (C) 2010-2017, Christopher Snowhill,
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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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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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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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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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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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#ifndef _HDCD_DECODE2_H_
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#define _HDCD_DECODE2_H_
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#include <stdint.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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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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* 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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int running_gain; /* 23-bit (1.22) fixed point gain level */
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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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* 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 max_gain;
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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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typedef struct {
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hdcd_state_t channel[2];
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int val_target_gain;
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int count_tg_mismatch;
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} hdcd_state_stereo_t;
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typedef enum {
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HDCD_PE_NEVER = 0,
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HDCD_PE_INTERMITTENT = 1,
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HDCD_PE_PERMANENT = 2,
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} hdcd_pe_t;
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typedef struct {
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int hdcd_detected;
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int errors; /* detectable errors */
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hdcd_pe_t peak_extend;
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int uses_transient_filter;
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float max_gain_adjustment; /* in dB, expected in the range -7.5 to 0.0 */
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} hdcd_detection_data_t;
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void hdcd_reset(hdcd_state_t *state, unsigned rate);
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void hdcd_process(hdcd_state_t *state, int *samples, int count, int stride);
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void hdcd_reset_stereo(hdcd_state_stereo_t *state, unsigned rate);
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void hdcd_process_stereo(hdcd_state_stereo_t *state, int *samples, int count);
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void hdcd_detect_reset(hdcd_detection_data_t *detect);
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void hdcd_detect_str(hdcd_detection_data_t *detect, char *str); /* char str[256] should be enough */
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/* there isn't a non-stereo version */
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void hdcd_detect_stereo(hdcd_state_stereo_t *state, hdcd_detection_data_t *detect);
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#ifdef __cplusplus
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}
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#endif
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#endif
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