<font color="#0000FF">NOTE:</font> This class does not exist in Open Inventor 10.0 and later.

This node has an effect only on Windows.

An SoVRMLAudioClip node specifies audio data that can be referenced by other nodes that require an audio source.

VRML97 SPECIFICATION

This section describes the expected behavior of the node in a conforming VRML97 browser application. In some cases, the application is responsible for implementing portions of the expected behavior. Open Inventor viewer classes and IVF classes implement some of the application behaviors.

This section may reference portions of the VRML97 specification that are not present in this help file. The complete VRML97 spec is available at http://www.web3d.org.

An SoVRMLAudioClip node specifies audio data that can be referenced by other nodes that require an audio source.

The description field is a textual description of the audio source. A browser is not required to display the description field but may choose to do so in addition to or in place of playing the sound.

The url field specifies the URL from which the sound is loaded. Browsers must support at least the wavefile format in uncompressed PCM format. It is recommended that browsers also support the MIDI file type 1 sound format. MIDI files are presumed to use the General MIDI patch set. See the section on URLs and URNs in "Concepts - URLs and URNs" for details on the url field. Results are not defined when the URL references unsupported data types.

The loop, startTime, and stopTime exposedFields and the isActive eventOut, and their effects on the SoVRMLAudioClip node, are discussed in detail in the "Concepts - Time Dependent Nodes" section. The "cycle" of an SoVRMLAudioClip is the length of time in seconds for one playing of the audio at the specified pitch.

The pitch field specifies a multiplier for the rate at which sampled sound is played. Only positive values are valid for pitch (a value of zero or less will produce undefined results). Changing the pitch field affects both the pitch and playback speed of a sound. A set_pitch event to an active SoVRMLAudioClip is ignored (and no pitch_changed eventOut is generated). If pitch is set to 2.0, the sound should be played one octave higher than normal and played twice as fast. For a sampled sound, the pitch field alters the sampling rate at which the sound is played. The proper implementation of the pitch control for MIDI (or other note sequence sound clip) is to multiply the tempo of the playback by the pitch value and adjust the MIDI Coarse Tune and Fine Tune controls to achieve the proper pitch change. The pitch field must be > 0.0.

A duration_changed event is sent whenever there is a new value for the "normal" duration of the clip. Typically this will only occur when the current url in use changes and the sound data has been loaded, indicating that the clip is playing a different sound source. The duration is the length of time in seconds for one cycle of the audio for a pitch set to 1.0. Changing the pitch field will not trigger a duration_changed event. A duration value of -1 implies the sound data has not yet loaded or the value is unavailable for some reason.

The isActive eventOut can be used by other nodes to determine if the clip is currently active. If an SoVRMLAudioClip is active, then it should be playing the sound corresponding to the sound time (i.e., in the sound's local time system with sample 0 at time 0):

   fmod (now - startTime, duration / pitch).

FILE FORMAT/DEFAULT

VRMLAudioClip {

description	""
loop	false
pitch	1.0
startTime	0
stopTime	0
pauseTime	0
resumeTime	0
url	[]
metadata	NULL

}

EVENTS

eventIn

SoSFString	set_description
SoSFBool	set_loop
SoSFFloat	set_pitch
SoSFTime	set_startTime
SoSFTime	set_stopTime
SoSFTime	set_pauseTime (Note: Not implemented)
SoSFTime	set_resumeTime (Note: Not implemented)
SoMFFilePathString	set_url
SoSFNode	set_metadata

eventOut

SoSFTime	duration_changed
SoSFTime	elapsedTime (Note: Not implemented)
SoSFBool	isActive
SoSFBool	isPaused (Note: Not implemented)
SoSFString	description_changed
SoSFBool	loop_changed
SoSFFloat	pitch_changed
SoSFTime	startTime_changed
SoSFTime	stopTime_changed
SoSFTime	pauseTime_changed (Note: Not implemented)
SoSFTime	resumeTime_changed (Note: Not implemented)
SoMFFilePathString	url_changed
SoSFNode	metadata_changed

Obsoletesince Open Inventor 9500 The VRML API is no longer supported. See section http://oivdoc95.vsg3d.com/content/compatibility-notes-4#Deprecation of the Reference Manual.

Reference