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/*
* Copyright (C) 2004 Alex Beregszaszi & Pierre Lombard
*
* This file is part of MPlayer.
*
* MPlayer 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.
*
* MPlayer 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 MPlayer; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include <math.h>
#include <limits.h>
#include "common/common.h"
#include "af.h"
// Data for specific instances of this filter
typedef struct af_extrastereo_s
{
float mul;
}af_extrastereo_t;
static int play_s16(struct af_instance* af, struct mp_audio* data, int f);
static int play_float(struct af_instance* af, struct mp_audio* data, int f);
// Initialization and runtime control
static int control(struct af_instance* af, int cmd, void* arg)
{
switch(cmd){
case AF_CONTROL_REINIT:{
// Sanity check
if(!arg) return AF_ERROR;
mp_audio_copy_config(af->data, (struct mp_audio*)arg);
mp_audio_force_interleaved_format(af->data);
mp_audio_set_num_channels(af->data, 2);
if (af->data->format == AF_FORMAT_FLOAT)
{
af->filter = play_float;
}// else
{
mp_audio_set_format(af->data, AF_FORMAT_S16);
af->filter = play_s16;
}
return af_test_output(af,(struct mp_audio*)arg);
}
}
return AF_UNKNOWN;
}
// Filter data through filter
static int play_s16(struct af_instance* af, struct mp_audio* data, int f)
{
af_extrastereo_t *s = af->priv;
register int i = 0;
int16_t *a = (int16_t*)data->planes[0]; // Audio data
int len = data->samples*data->nch; // Number of samples
int avg, l, r;
for (i = 0; i < len; i+=2)
{
avg = (a[i] + a[i + 1]) / 2;
l = avg + (int)(s->mul * (a[i] - avg));
r = avg + (int)(s->mul * (a[i + 1] - avg));
a[i] = MPCLAMP(l, SHRT_MIN, SHRT_MAX);
a[i + 1] = MPCLAMP(r, SHRT_MIN, SHRT_MAX);
}
return 0;
}
static int play_float(struct af_instance* af, struct mp_audio* data, int f)
{
af_extrastereo_t *s = af->priv;
register int i = 0;
float *a = (float*)data->planes[0]; // Audio data
int len = data->samples * data->nch; // Number of samples
float avg, l, r;
for (i = 0; i < len; i+=2)
{
avg = (a[i] + a[i + 1]) / 2;
l = avg + (s->mul * (a[i] - avg));
r = avg + (s->mul * (a[i + 1] - avg));
a[i] = af_softclip(l);
a[i + 1] = af_softclip(r);
}
return 0;
}
// Allocate memory and set function pointers
static int af_open(struct af_instance* af){
af->control=control;
af->filter=play_s16;
return AF_OK;
}
#define OPT_BASE_STRUCT af_extrastereo_t
struct af_info af_info_extrastereo = {
.info = "Increase difference between audio channels",
.name = "extrastereo",
.flags = AF_FLAGS_NOT_REENTRANT,
.open = af_open,
.priv_size = sizeof(af_extrastereo_t),
.options = (const struct m_option[]) {
OPT_FLOAT("mul", mul, 0, OPTDEF_FLOAT(2.5)),
{0}
},
};
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