rockbox/lib/rbcodec/dsp/afr.c
Chiwen Chang 3ae0f32ac3 three new DSPs
perceptual bass enhancement
- a bbe-ish group delay corrction with Biophonic EQ boost.
- precut

auditory fatigue reduction
-reduce signal in frequency that may trigger temporary threshold shift

haas surround
-frequency between f(x1) and f(x2) is always bypassed.
-can apply to side only.

Change-Id: Icb6355ce9b1c99bf2c58c9385c3c411c0ae209d3
2015-01-19 19:34:01 +01:00

147 lines
4 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2014 by Chiwen Chang
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "afr.h"
#include "config.h"
#include "fixedpoint.h"
#include "fracmul.h"
#include "settings.h"
#include "dsp_proc_entry.h"
#include "dsp_filter.h"
/* Auditory fatigue reduction */
static int afr_strength = 0;
static struct dsp_filter afr_filters[4];
static void dsp_afr_flush(void)
{
for (int i = 0 ;i < 4;i++)
filter_flush(&afr_filters[i]);
}
static void strength_update(unsigned int fout)
{
int hs=0, ls=0, drop3k=0;
switch (afr_strength)
{
/* not called if afr_strength == 0 (disabled) */
case 1:
hs=-29; ls=0; drop3k=-13;
break;
case 2:
hs=-58; ls=-5; drop3k=-29;
break;
case 3:
hs=-72; ls=-5; drop3k=-48;
break;
}
filter_bishelf_coefs(fp_div(8000, fout, 32),
fp_div(20000, fout, 32),
0, (hs/2), 0,
&afr_filters[0]);
filter_pk_coefs(fp_div(8000, fout, 32), 28, hs,
&afr_filters[1]);
filter_pk_coefs(fp_div(3150, fout, 32), 28, drop3k,
&afr_filters[2]);
filter_bishelf_coefs(fp_div(200, fout, 32),
fp_div(1280, fout, 32),
ls, 0, 0,
&afr_filters[3]);
}
void dsp_afr_enable(int var)
{
if (var == afr_strength)
return; /* No setting change */
bool was_enabled = afr_strength > 0;
afr_strength = var;
bool now_enabled = var > 0;
if (was_enabled == now_enabled && !now_enabled)
return;
/* If changing status, enable or disable it; if already enabled push
additional DSP_PROC_INIT messages with value = 1 to force-update the
filters */
struct dsp_config *dsp = dsp_get_config(CODEC_IDX_AUDIO);
dsp_proc_enable(dsp, DSP_PROC_AFR, now_enabled);
}
static void afr_reduce_process(struct dsp_proc_entry *this,
struct dsp_buffer **buf_p)
{
struct dsp_buffer *buf = *buf_p;
for (int i = 0; i < 4; i++)
filter_process(&afr_filters[i], buf->p32, buf->remcount,
buf->format.num_channels);
(void)this;
}
/* DSP message hook */
static intptr_t afr_configure(struct dsp_proc_entry *this,
struct dsp_config *dsp,
unsigned int setting,
intptr_t value)
{
/* This only attaches to the audio (codec) DSP */
switch (setting)
{
case DSP_PROC_INIT:
if (value == 0)
{
/* Coming online; was disabled */
this->process = afr_reduce_process;
dsp_afr_flush();
dsp_proc_activate(dsp, DSP_PROC_AFR, true);
}
/* else additional forced messages */
strength_update(dsp_get_output_frequency(dsp));
break;
case DSP_FLUSH:
/* Discontinuity; clear filters */
dsp_afr_flush();
break;
case DSP_SET_OUT_FREQUENCY:
/* New output frequency */
strength_update(value);
break;
}
return 1;
}
/* Database entry */
DSP_PROC_DB_ENTRY(
AFR,
afr_configure);