1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
/*
* This filter adds a center channel to the audio stream by
* averaging the left and right channel.
* There are two runtime controls one for setting which channel
* to insert the center-audio into called AF_CONTROL_SUB_CH.
*
* FIXME: implement a high-pass filter for better results.
*
* copyright (c) 2005 Alex Beregszaszi
*
* 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 "af.h"
// Data for specific instances of this filter
typedef struct af_center_s
{
int ch; // Channel number which to insert the filtered data
}af_center_t;
// Initialization and runtime control
static int control(struct af_instance_s* af, int cmd, void* arg)
{
af_center_t* s = af->setup;
switch(cmd){
case AF_CONTROL_REINIT:{
// Sanity check
if(!arg) return AF_ERROR;
af->data->rate = ((af_data_t*)arg)->rate;
af->data->nch = max(s->ch+1,((af_data_t*)arg)->nch);
af->data->format = AF_FORMAT_FLOAT_NE;
af->data->bps = 4;
return af_test_output(af,(af_data_t*)arg);
}
case AF_CONTROL_COMMAND_LINE:{
int ch=1;
sscanf(arg,"%i", &ch);
return control(af,AF_CONTROL_CENTER_CH | AF_CONTROL_SET, &ch);
}
case AF_CONTROL_CENTER_CH | AF_CONTROL_SET: // Requires reinit
// Sanity check
if((*(int*)arg >= AF_NCH) || (*(int*)arg < 0)){
mp_msg(MSGT_AFILTER, MSGL_ERR, "[sub] Center channel number must be between "
" 0 and %i current value is %i\n", AF_NCH-1, *(int*)arg);
return AF_ERROR;
}
s->ch = *(int*)arg;
return AF_OK;
case AF_CONTROL_CENTER_CH | AF_CONTROL_GET:
*(int*)arg = s->ch;
return AF_OK;
}
return AF_UNKNOWN;
}
// Deallocate memory
static void uninit(struct af_instance_s* af)
{
if(af->data)
free(af->data);
if(af->setup)
free(af->setup);
}
// Filter data through filter
static af_data_t* play(struct af_instance_s* af, af_data_t* data)
{
af_data_t* c = data; // Current working data
af_center_t* s = af->setup; // Setup for this instance
float* a = c->audio; // Audio data
int len = c->len/4; // Number of samples in current audio block
int nch = c->nch; // Number of channels
int ch = s->ch; // Channel in which to insert the center audio
register int i;
// Run filter
for(i=0;i<len;i+=nch){
// Average left and right
a[i+ch] = (a[i]/2) + (a[i+1]/2);
}
return c;
}
// Allocate memory and set function pointers
static int af_open(af_instance_t* af){
af_center_t* s;
af->control=control;
af->uninit=uninit;
af->play=play;
af->mul=1;
af->data=calloc(1,sizeof(af_data_t));
af->setup=s=calloc(1,sizeof(af_center_t));
if(af->data == NULL || af->setup == NULL)
return AF_ERROR;
// Set default values
s->ch = 1; // Channel nr 2
return AF_OK;
}
// Description of this filter
af_info_t af_info_center = {
"Audio filter for adding a center channel",
"center",
"Alex Beregszaszi",
"",
AF_FLAGS_NOT_REENTRANT,
af_open
};
|
