[FFmpeg-cvslog] af_hdcd: Code comments update
Burt P
git at videolan.org
Sun Aug 21 21:54:48 EEST 2016
ffmpeg | branch: master | Burt P <pburt0 at gmail.com> | Sun Aug 21 13:00:22 2016 -0500| [400e2acd112d35fa411c91cf02c638450b0e7c8c] | committer: Burt P
af_hdcd: Code comments update
Signed-off-by: Burt P <pburt0 at gmail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=400e2acd112d35fa411c91cf02c638450b0e7c8c
---
libavfilter/af_hdcd.c | 181 ++++++++++++++++++++++++++------------------------
1 file changed, 95 insertions(+), 86 deletions(-)
diff --git a/libavfilter/af_hdcd.c b/libavfilter/af_hdcd.c
index 9377eb6..37b427a 100644
--- a/libavfilter/af_hdcd.c
+++ b/libavfilter/af_hdcd.c
@@ -1,40 +1,46 @@
/*
- Copyright (C) 2010, Chris Moeller,
- All rights reserved.
- Optimizations by Gumboot
- Redistribution and use in source and binary forms, with or without modification,
- are permitted provided that the following conditions are met:
- 1. Redistributions of source code must retain the above copyright
- notice, this list of conditions and the following disclaimer.
- 2. Redistributions in binary form must reproduce the above copyright
- notice, this list of conditions and the following disclaimer in the
- documentation and/or other materials provided with the distribution.
- 3. The names of its contributors may not be used to endorse or promote
- products derived from this software without specific prior written
- permission.
- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
- CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
- LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
- NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Copyright (C) 2010, Chris Moeller,
+ * All rights reserved.
+ * Optimizations by Gumboot
+ * Additional work by Burt P.
+ * Original code reverse engineered from HDCD decoder library by Christopher Key,
+ * which was likely reverse engineered from Windows Media Player.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The names of its contributors may not be used to endorse or promote
+ * products derived from this software without specific prior written
+ * permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
- Original code reverse engineered from HDCD decoder library by Christopher Key,
- which was likely reverse engineered from Windows Media Player.
+ * HDCD is High Definition Compatible Digital
+ * http://wiki.hydrogenaud.io/index.php?title=High_Definition_Compatible_Digital
+ *
+ * More information about HDCD-encoded audio CDs:
+ * http://www.audiomisc.co.uk/HFN/HDCD/Enigma.html
+ * http://www.audiomisc.co.uk/HFN/HDCD/Examined.html
*/
-/*
- HDCD is High Definition Compatible Digital
- More information about HDCD-encoded audio CDs:
- http://www.audiomisc.co.uk/HFN/HDCD/Enigma.html
- http://www.audiomisc.co.uk/HFN/HDCD/Examined.html
+/**
+ * @file
+ * HDCD decoding filter
*/
#include "libavutil/opt.h"
@@ -820,34 +826,34 @@ typedef struct {
uint64_t window;
unsigned char readahead;
- /* arg is set when a packet prefix is found.
- * control is the active control code, where
- * bit 0-3: target_gain, 4-bit (3.1) fixed-point value
- * bit 4 : peak_extend
- * bit 5 : transient_filter
- * bit 6,7: always zero */
- unsigned char arg, control;
- unsigned sustain, sustain_reset; /* code detect timer */
+ /** arg is set when a packet prefix is found.
+ * control is the active control code, where
+ * bit 0-3: target_gain, 4-bit (3.1) fixed-point value
+ * bit 4 : peak_extend
+ * bit 5 : transient_filter
+ * bit 6,7: always zero */
+ uint8_t arg, control;
+ unsigned int sustain, sustain_reset; /**< code detect timer */
- int running_gain; /* 11-bit (3.8) fixed point, extended from target_gain */
+ int running_gain; /**< 11-bit (3.8) fixed point, extended from target_gain */
/* counters */
- int code_counterA; /* 8-bit format packet */
- int code_counterA_almost; /* looks like an A code, but a bit expected to be 0 is 1 */
- int code_counterB; /* 16-bit format packet, 8-bit code, 8-bit XOR of code */
- int code_counterB_checkfails; /* looks like a B code, but doesn't pass the XOR check */
- int code_counterC; /* packet prefix was found, expect a code */
- int code_counterC_unmatched; /* told to look for a code, but didn't find one */
- int count_peak_extend; /* valid packets where peak_extend was enabled */
- int count_transient_filter; /* valid packets where filter was detected */
- /* target_gain is a 4-bit (3.1) fixed-point value, always
- * negative, but stored positive.
- * The 16 possible values range from -7.5 to 0.0 dB in
- * steps of 0.5, but no value below -6.0 dB should appear. */
- int gain_counts[16]; /* for cursiosity, mostly */
+ int code_counterA; /**< 8-bit format packet */
+ int code_counterA_almost; /**< looks like an A code, but a bit expected to be 0 is 1 */
+ int code_counterB; /**< 16-bit format packet, 8-bit code, 8-bit XOR of code */
+ int code_counterB_checkfails; /**< looks like a B code, but doesn't pass the XOR check */
+ int code_counterC; /**< packet prefix was found, expect a code */
+ int code_counterC_unmatched; /**< told to look for a code, but didn't find one */
+ int count_peak_extend; /**< valid packets where peak_extend was enabled */
+ int count_transient_filter; /**< valid packets where filter was detected */
+ /** target_gain is a 4-bit (3.1) fixed-point value, always
+ * negative, but stored positive.
+ * The 16 possible values range from -7.5 to 0.0 dB in
+ * steps of 0.5, but no value below -6.0 dB should appear. */
+ int gain_counts[16];
int max_gain;
- /* occurences of code detect timer expiring without detecting
- * a code. -1 for timer never set. */
+ /** occurences of code detect timer expiring without detecting
+ * a code. -1 for timer never set. */
int count_sustain_expired;
} hdcd_state_t;
@@ -866,8 +872,8 @@ static const char * const pe_str[] = {
#define HDCD_PROCESS_STEREO_DEFAULT 1
#define HDCD_MAX_CHANNELS 2
-/* convert to float from 4-bit (3.1) fixed-point
- * the always-negative value is stored positive, so make it negative */
+/** convert to float from 4-bit (3.1) fixed-point
+ * the always-negative value is stored positive, so make it negative */
#define GAINTOFLOAT(g) (g) ? -(float)(g>>1) - ((g & 1) ? 0.5 : 0.0) : 0.0
#define HDCD_ANA_OFF 0
@@ -894,38 +900,40 @@ typedef struct HDCDContext {
const AVClass *class;
hdcd_state_t state[HDCD_MAX_CHANNELS];
- /* use hdcd_*_stereo() functions to process both channels together.
- * -af hdcd=process_stereo=0 for off
- * -af hdcd=process_stereo=1 for on
- * default is HDCD_PROCESS_STEREO_DEFAULT */
+ /* AVOption members */
+ /** use hdcd_*_stereo() functions to process both channels together.
+ * -af hdcd=process_stereo=0 for off
+ * -af hdcd=process_stereo=1 for on
+ * default is HDCD_PROCESS_STEREO_DEFAULT */
int process_stereo;
- /* always extend peaks above -3dBFS even if PE isn't signaled
- * -af hdcd=force_pe=0 for off
- * -af hdcd=force_pe=1 for on
- * default is off */
+ /** always extend peaks above -3dBFS even if PE isn't signaled
+ * -af hdcd=force_pe=0 for off
+ * -af hdcd=force_pe=1 for on
+ * default is off */
int force_pe;
- /* analyze mode replaces the audio with a solid tone and adjusts
- * the amplitude to signal some specific aspect of the decoding
- * process. See docs or HDCD_ANA_* defines. */
+ /** analyze mode replaces the audio with a solid tone and adjusts
+ * the amplitude to signal some specific aspect of the decoding
+ * process. See docs or HDCD_ANA_* defines. */
int analyze_mode;
- int ana_snb; /* used in tone generation */
+ int ana_snb; /**< used in tone generation */
+ /* end AVOption members */
- /* config_input() and config_output() scan links for any resampling
- * or format changes. If found, warnings are issued and bad_config
- * is set. */
+ /** config_input() and config_output() scan links for any resampling
+ * or format changes. If found, warnings are issued and bad_config
+ * is set. */
int bad_config;
- AVFilterContext *fctx; /* filter context for logging errors */
- int sample_count; /* used in error logging */
- int val_target_gain; /* last matching target_gain in both channels */
+ AVFilterContext *fctx; /**< filter context for logging errors */
+ int sample_count; /**< used in error logging */
+ int val_target_gain; /**< last matching target_gain in both channels */
/* User information/stats */
- int hdcd_detected;
- int det_errors; /* detectable errors */
- hdcd_pe_t peak_extend;
- int uses_transient_filter; /* detected, but not implemented */
- float max_gain_adjustment; /* in dB, expected in the range -6.0 to 0.0 */
+ int hdcd_detected; /**< Valid HDCD coding was detected */
+ int det_errors; /**< detectable errors */
+ hdcd_pe_t peak_extend; /**< peak exted used */
+ int uses_transient_filter; /**< transient filter flag detected */
+ float max_gain_adjustment; /**< in dB, expected in the range -7.5 to 0.0 */
} HDCDContext;
#define OFFSET(x) offsetof(HDCDContext, x)
@@ -976,7 +984,7 @@ static void hdcd_reset(hdcd_state_t *state, unsigned rate)
state->count_sustain_expired = -1;
}
-/* update the user info/counters */
+/** update the user info/counters */
static void hdcd_update_info(hdcd_state_t *state)
{
if (state->control & 16) state->count_peak_extend++;
@@ -1242,7 +1250,7 @@ static int hdcd_scan_stereo(HDCDContext *ctx, const int32_t *samples, int max)
return result;
}
-/* encode a value in the given sample by adjusting the amplitude */
+/** encode a value in the given sample by adjusting the amplitude */
static int32_t hdcd_analyze_gen(int32_t sample, unsigned int v, unsigned int maxv)
{
float sflt = sample, vv = v;
@@ -1252,8 +1260,8 @@ static int32_t hdcd_analyze_gen(int32_t sample, unsigned int v, unsigned int max
return (int32_t)sflt;
}
-/* behaves like hdcd_envelope(), but encodes processing information in
- * a way that is audible (and visible in an audio editor) to aid analysis. */
+/** behaves like hdcd_envelope(), but encodes processing information in
+ * a way that is audible (and visible in an audio editor) to aid analysis. */
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)
{
static const int maxg = 0xf << 7;
@@ -1313,6 +1321,7 @@ static int hdcd_analyze(int32_t *samples, int count, int stride, int gain, int t
return gain;
}
+/** apply HDCD decoding parameters to a series of samples */
static int hdcd_envelope(int32_t *samples, int count, int stride, int gain, int target_gain, int extend)
{
int i;
@@ -1372,7 +1381,7 @@ static int hdcd_envelope(int32_t *samples, int count, int stride, int gain, int
return gain;
}
-/* extract fields from control code */
+/** extract fields from control code */
static void hdcd_control(HDCDContext *ctx, hdcd_state_t *state, int *peak_extend, int *target_gain)
{
*peak_extend = (ctx->force_pe || state->control & 16);
@@ -1500,7 +1509,7 @@ static void hdcd_process_stereo(HDCDContext *ctx, int32_t *samples, int count)
ctx->state[1].running_gain = gain[1];
}
-/* tone generator: sample_number, frequency, sample_rate, amplitude */
+/** tone generator: sample_number, frequency, sample_rate, amplitude */
#define TONEGEN16(sn, f, sr, a) (int16_t)(sin((6.28318530718 * (sn) * (f)) /(sr)) * (a) * 0x7fff)
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
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