blob: 18e4815638062b0a2ff0875bb1a3260f9f498264 (
plain)
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
|
/*
* Purpose: Application to local playback buffer import routine for vmix (int)
*/
/*
*
* This file is part of Open Sound System.
*
* Copyright (C) 4Front Technologies 1996-2008.
*
* This this source file is released under GPL v2 license (no other versions).
* See the COPYING file included in the main directory of this source
* distribution for the license terms and conditions.
*
*/
/*
* Mixing function for virtual devices
*/
vmix_mixer_t *mixer = portc->mixer;
vmix_engine_t *eng = &mixer->play_engine;
dmap_t *dmap = audio_engines[portc->audio_dev]->dmap_out;
int frame_size;
int inptr, inmax;
int used_channels;
int i, ch, nch;
int vol;
/*
* Initial setup
*/
frame_size = sizeof (*inp);
inmax = dmap->bytes_in_use / frame_size;
inptr = portc->play_dma_pointer / frame_size;
inp = (BUFFER_TYPE) dmap->dmabuf;
used_channels = portc->channels;
if (used_channels > eng->channels)
used_channels = eng->channels;
/* ignored_channels = portc->channels - used_channels; */
/*
* Handle mono playback by playing the mono stream twice (for left and right ch)
*/
nch=used_channels;
if (nch<2)nch=2;
/*
* Do the mixing
*/
for (ch = 0; ch < nch; ch++)
{
int ip = inptr + (ch%used_channels);
int vu = portc->vu[ch % 2];
int *chbuf = eng->chbufs[ch+portc->play_choffs];
i = portc->volume[ch%2];
vol = vmix_db_table[i / 5];
vu = vu * 65536;
for (i = 0; i < nsamples; i++)
{
int tmp;
/*
* Convert the sample to right endianess.
*/
tmp = INT_OUTMIX(VMIX_BYTESWAP (inp[ip]));
tmp = (tmp * vol) / VMIX_VOL_SCALE;
*chbuf++ += tmp;
ip = (ip + portc->channels) % inmax;
/* VU meter */
if (tmp < 0)
tmp = -tmp;
if (tmp > vu)
vu = tmp;
}
if (ch < 2)
{ /* Save left/right VU meters */
vu = vu / 65536;
portc->vu[ch] = vu;
}
}
/*
* Finally save the state variables
*/
portc->play_dma_pointer =
(portc->play_dma_pointer +
nsamples * frame_size * portc->channels) % dmap->bytes_in_use;
|
