source: roaraudio/doc/man3/roar_vs_volume_get.3 @ 5041:236c1b3b1a30

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1.TH "roar_vs_volume_get" "3" "May 2011" "RoarAudio" "RoarAudio Programmer's Manual"
2
3.SH NAME
4roar_vs_volume_get, roar_vs_volume_mono, roar_vs_volume_stereo \- Get or set volume for audio stream
5
6.SH SYNOPSIS
7
8#include <roaraudio.h>
9
10int     roar_vs_volume_get    (roar_vs_t * vss, float * l, float * r, int * error);
11
12int     roar_vs_volume_mono   (roar_vs_t * vss, float c, int * error);
13
14int     roar_vs_volume_stereo (roar_vs_t * vss, float l, float r, int * error);
15
16.SH "DESCRIPTION"
17Those functions are used to get or set volume for the given stream.
18
19\fBroar_vs_volume_get()\fR gets the volume for the given stream in stereo form as
20a left and a right component (L/R). If you need the mono volume just devide the sum of both
21by two. See examples below.
22
23\fBroar_vs_volume_mono()\fR sets the mono volume for the stream. Balance information is not kept.
24
25\fBroar_vs_volume_stereo()\fR sets the stereo volume for the stream as left and rigth component (L/R).
26
27.SH "PARAMETERS"
28.TP
29\fBvss\fR
30The VS object for wich volume is get or set.
31
32.TP
33\fBl\fR, \fBr\fR, \fBc\fR
34The volume for left, right or center (mono) channel. Value is a float in range zero to one.
35Zero means this channel is fully muted. One means the channel is passed without altering the amplitude.
36
37Small numerical errors are detected and corrected. Bigger errors will result in a out of range error.
38
39Note that to mute the stream you MUST NOT use volume setting but \fBroar_vs_mute\fR(3).
40
41.TP
42\fBerror\fR
43This is a pointer to a integer used to store the error value in case of error.
44This can be NULL if not used but it is very recommended to use this error value to report
45good error messages to the user.
46
47.SH "RETURN VALUE"
48On success these calls return 0.  On error, \-1 is returned.
49
50.SH "EXAMPLES"
51Getting mono volume:
52
53 float l, r, c;
54 int err;
55
56 if ( roar_vs_volume_get(vss, &l, &r, &err) == -1 ) {
57  /* handle error */
58 }
59 c = (l + r)/2.;
60
61.SH "SEE ALSO"
62\fBroarvs\fR(7),
63\fBlibroar\fR(7),
64\fBRoarAudio\fR(7).
65
66.\" ll
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