roar_vs_volume_get(3) [debian man page]

roar_vs_volume_get(3)					   RoarAudio Programmer's Manual				     roar_vs_volume_get(3)

NAME

       roar_vs_volume_get, roar_vs_volume_mono, roar_vs_volume_stereo - Get or set volume for audio stream

SYNOPSIS

       #include <roaraudio.h>

       int     roar_vs_volume_get    (roar_vs_t * vss, float * l, float * r, int * error);

       int     roar_vs_volume_mono   (roar_vs_t * vss, float c, int * error);

       int     roar_vs_volume_stereo (roar_vs_t * vss, float l, float r, int * error);

DESCRIPTION

       Those functions are used to get or set volume for the given stream.

       roar_vs_volume_get() gets the volume for the given stream in stereo form as a left and a right component (L/R). If you need the mono volume
       just devide the sum of both by two. See examples below.

       roar_vs_volume_mono() sets the mono volume for the stream. Balance information is not kept.

       roar_vs_volume_stereo() sets the stereo volume for the stream as left and rigth component (L/R).

PARAMETERS

       vss    The VS object for wich volume is get or set.

       l, r, c
	      The volume for left, right or center (mono) channel. Value is a float in range zero to one.  Zero means this channel is fully muted.
	      One means the channel is passed without altering the amplitude.

	      Small numerical errors are detected and corrected. Bigger errors will result in a out of range error.

	      Note that to mute the stream you MUST NOT use volume setting but roar_vs_mute(3).

       error  This  is	a pointer to a integer used to store the error value in case of error.	This can be NULL if not used but it is very recom-
	      mended to use this error value to report good error messages to the user.

RETURN VALUE

       On success these calls return 0.  On error, -1 is returned.

EXAMPLES

       Getting mono volume:

	float l, r, c;
	int err;

	if ( roar_vs_volume_get(vss, &l, &r, &err) == -1 ) {
	 /* handle error */
	}
	c = (l + r)/2.;

SEE ALSO

       roarvs(7), libroar(7), RoarAudio(7).

RoarAudio							     May 2011						     roar_vs_volume_get(3)

roar_vs_stream(3)					   RoarAudio Programmer's Manual					 roar_vs_stream(3)

NAME

       roar_vs_stream - Set up stream parameters for VS object

SYNOPSIS

       #include <roaraudio.h>

       int roar_vs_stream(roar_vs_t * vss, const struct roar_audio_info * info, int dir, int * error);

DESCRIPTION

       This  function  asks a VS object opened by roar_vs_new_from_con(3) or roar_vs_new(3) to open the data connection using the audio parameters
       info and the stream direction dir.

       This function needs to be called before data is read or written if one of the above functions is used to create the VS object.

       This function is also used to provide parameters for the file mode (which is started by using roar_vs_file(3)  or  roar_vs_file_simple(3)).
       To  play  back  a  file	this  is not needed in a common case as the VS API tries to find correct parameters.  It is required for all other
       stream directions. See roar_vs_file(3) and roar_vs_file_simple(3) for more information.

       On failture this function can be called again with diffrent parameters.

PARAMETERS

       vss    The VS object to be updated.

       info   This is a pointer to the roar_audio_info structure storing the audio format parameters.  The structure contains the following  meme-
	      bers: rate (sample rate), bits (bits per sample), channels (channels per frame) and codec.

       dir    This  is	the stream direction. Common values include ROAR_DIR_PLAY for waveform playback, ROAR_DIR_MONITOR for waveform monitoring,
	      ROAR_DIR_RECORD for waveform recording.  For MIDI ROAR_DIR_MIDI_IN and ROAR_DIR_MIDI_OUT is used.

       error  This is a pointer to a integer used to store the error value in case of error.  This can be NULL if not used but it is  very  recom-
	      mended to use this error value to report good error messages to the user.

RETURN VALUE

       On success these calls return 0.  On error, -1 is returned.

EXAMPLES

	struct roar_audio_info info;
	int err;

	if ( roar_profile2info(&info, "isdn-eu") == -1 ) {
	 // error handling.
	}

	if ( roar_vs_stream(vss, &info, ROAR_DIR_PLAY, &err) == -1 ) {
	 // error handling.
	}

SEE ALSO

       roar_vs_file(3), roar_vs_file_simple(3), roarvs(7), libroar(7), RoarAudio(7).

RoarAudio							     June 2011							 roar_vs_stream(3)