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/*
* Copyright (C)2002 Anders Johansson ajh@atri.curtin.edu.au
*
* 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 "af.h"
// Data for specific instances of this filter
typedef struct af_volume_s
{
float level[AF_NCH]; // Gain level for each channel
int soft; // Enable/disable soft clipping
int fast; // Use fix-point volume control
} af_volume_t;
// Initialization and runtime control
static int control(struct af_instance *af, int cmd, void *arg)
{
af_volume_t *s = (af_volume_t *)af->setup;
switch (cmd) {
case AF_CONTROL_REINIT:
// Sanity check
if (!arg)
return AF_ERROR;
mp_audio_copy_config(af->data, (struct mp_audio *)arg);
if (s->fast && (((struct mp_audio *)arg)->format != (AF_FORMAT_FLOAT_NE)))
mp_audio_set_format(af->data, AF_FORMAT_S16_NE);
else {
// Cutoff set to 10Hz for forgetting factor
mp_audio_set_format(af->data, AF_FORMAT_FLOAT_NE);
}
return af_test_output(af, (struct mp_audio *)arg);
case AF_CONTROL_COMMAND_LINE: {
float v = 1000.0;
float vol[AF_NCH];
int i;
sscanf((char *)arg, "%f:%i:%i", &v, &s->soft, &s->fast);
float dest = 0.0;
if (v < 1000)
af_from_dB(1, &v, &dest, 20.0, -200.0, 60.0);
for (i = 0; i < AF_NCH; i++)
vol[i] = dest;
return control(af, AF_CONTROL_VOLUME_LEVEL | AF_CONTROL_SET, vol);
}
case AF_CONTROL_VOLUME_LEVEL | AF_CONTROL_SET:
memcpy(s->level, arg, sizeof(float) * AF_NCH);
return AF_OK;
case AF_CONTROL_VOLUME_LEVEL | AF_CONTROL_GET:
memcpy(arg, s->level, sizeof(float) * AF_NCH);
return AF_OK;
}
return AF_UNKNOWN;
}
// Deallocate memory
static void uninit(struct af_instance *af)
{
free(af->data);
free(af->setup);
}
// Filter data through filter
static struct mp_audio *play(struct af_instance *af, struct mp_audio *data)
{
struct mp_audio *c = data; // Current working data
af_volume_t *s = (af_volume_t *)af->setup; // Setup for this instance
int nch = c->nch; // Number of channels
if (af->data->format == AF_FORMAT_S16_NE) {
int16_t *a = (int16_t *)c->audio; // Audio data
int len = c->len / 2; // Number of samples
for (int ch = 0; ch < nch; ch++) {
int vol = 256.0 * s->level[ch];
if (vol != 256) {
for (int i = ch; i < len; i += nch) {
int x = (a[i] * vol) >> 8;
a[i] = clamp(x, SHRT_MIN, SHRT_MAX);
}
}
}
} else if (af->data->format == AF_FORMAT_FLOAT_NE) {
float *a = (float *)c->audio; // Audio data
int len = c->len / 4; // Number of samples
for (int ch = 0; ch < nch; ch++) {
// Volume control (fader)
if (s->level[ch] != 1.0) {
for (int i = ch; i < len; i += nch) {
float x = a[i];
// Set volume
x *= s->level[ch];
/* Soft clipping, the sound of a dream, thanks to Jon Wattes
post to Musicdsp.org */
a[i] = s->soft ? af_softclip(x) : clamp(x, -1.0, 1.0);
}
}
}
}
return c;
}
// Allocate memory and set function pointers
static int af_open(struct af_instance *af)
{
af->control = control;
af->uninit = uninit;
af->play = play;
af->mul = 1;
af->data = calloc(1, sizeof(struct mp_audio));
af->setup = calloc(1, sizeof(af_volume_t));
if (af->data == NULL || af->setup == NULL)
return AF_ERROR;
// Enable volume control and set initial volume to 0dB.
for (int i = 0; i < AF_NCH; i++)
((af_volume_t *)af->setup)->level[i] = 1.0;
return AF_OK;
}
// Description of this filter
struct af_info af_info_volume = {
.info = "Volume control audio filter",
.name = "volume",
.flags = AF_FLAGS_NOT_REENTRANT,
.open = af_open,
};
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