mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-21 19:53:59 +08:00
475be4d85a
isdn source code uses a not-current coding style. Update the coding style used on a per-line basis so that git diff -w shows only elided blank lines at EOF. Done with emacs and some scripts and some typing. Built x86 allyesconfig. No detected change in objdump -d or size. Signed-off-by: Joe Perches <joe@perches.com>
111 lines
3.5 KiB
C
111 lines
3.5 KiB
C
/*
|
|
* SpanDSP - a series of DSP components for telephony
|
|
*
|
|
* ec_disable_detector.h - A detector which should eventually meet the
|
|
* G.164/G.165 requirements for detecting the
|
|
* 2100Hz echo cancellor disable tone.
|
|
*
|
|
* Written by Steve Underwood <steveu@coppice.org>
|
|
*
|
|
* Copyright (C) 2001 Steve Underwood
|
|
*
|
|
* All rights reserved.
|
|
*
|
|
* 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 program 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 General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*
|
|
*/
|
|
|
|
#include "dsp_biquad.h"
|
|
|
|
struct ec_disable_detector_state {
|
|
struct biquad2_state notch;
|
|
int notch_level;
|
|
int channel_level;
|
|
int tone_present;
|
|
int tone_cycle_duration;
|
|
int good_cycles;
|
|
int hit;
|
|
};
|
|
|
|
|
|
#define FALSE 0
|
|
#define TRUE (!FALSE)
|
|
|
|
static inline void
|
|
echo_can_disable_detector_init(struct ec_disable_detector_state *det)
|
|
{
|
|
/* Elliptic notch */
|
|
/* This is actually centred at 2095Hz, but gets the balance we want, due
|
|
to the asymmetric walls of the notch */
|
|
biquad2_init(&det->notch,
|
|
(int32_t)(-0.7600000 * 32768.0),
|
|
(int32_t)(-0.1183852 * 32768.0),
|
|
(int32_t)(-0.5104039 * 32768.0),
|
|
(int32_t)(0.1567596 * 32768.0),
|
|
(int32_t)(1.0000000 * 32768.0));
|
|
|
|
det->channel_level = 0;
|
|
det->notch_level = 0;
|
|
det->tone_present = FALSE;
|
|
det->tone_cycle_duration = 0;
|
|
det->good_cycles = 0;
|
|
det->hit = 0;
|
|
}
|
|
/*- End of function --------------------------------------------------------*/
|
|
|
|
static inline int
|
|
echo_can_disable_detector_update(struct ec_disable_detector_state *det,
|
|
int16_t amp)
|
|
{
|
|
int16_t notched;
|
|
|
|
notched = biquad2(&det->notch, amp);
|
|
/* Estimate the overall energy in the channel, and the energy in
|
|
the notch (i.e. overall channel energy - tone energy => noise).
|
|
Use abs instead of multiply for speed (is it really faster?).
|
|
Damp the overall energy a little more for a stable result.
|
|
Damp the notch energy a little less, so we don't damp out the
|
|
blip every time the phase reverses */
|
|
det->channel_level += ((abs(amp) - det->channel_level) >> 5);
|
|
det->notch_level += ((abs(notched) - det->notch_level) >> 4);
|
|
if (det->channel_level > 280) {
|
|
/* There is adequate energy in the channel.
|
|
Is it mostly at 2100Hz? */
|
|
if (det->notch_level * 6 < det->channel_level) {
|
|
/* The notch says yes, so we have the tone. */
|
|
if (!det->tone_present) {
|
|
/* Do we get a kick every 450+-25ms? */
|
|
if (det->tone_cycle_duration >= 425 * 8
|
|
&& det->tone_cycle_duration <= 475 * 8) {
|
|
det->good_cycles++;
|
|
if (det->good_cycles > 2)
|
|
det->hit = TRUE;
|
|
}
|
|
det->tone_cycle_duration = 0;
|
|
}
|
|
det->tone_present = TRUE;
|
|
} else
|
|
det->tone_present = FALSE;
|
|
det->tone_cycle_duration++;
|
|
} else {
|
|
det->tone_present = FALSE;
|
|
det->tone_cycle_duration = 0;
|
|
det->good_cycles = 0;
|
|
}
|
|
return det->hit;
|
|
}
|
|
/*- End of function --------------------------------------------------------*/
|
|
/*- End of file ------------------------------------------------------------*/
|