Interface AudioDevice
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- All Known Subinterfaces:
AudioDevice3D
,AudioDevice3DL2
- All Known Implementing Classes:
AudioEngine
,AudioEngine3D
,AudioEngine3DL2
,JavaSoundMixer
public interface AudioDevice
The AudioDevice Class defines and encapsulates the audio device's basic information and characteristics.A Java3D application running on a particular machine could have one of several options available to it for playing the audio image created by the sound renderer. Perhaps the machine Java3D is executing on has more than one sound card (e.g., one that is a Wave Table Synthesis card and the other with accelerated sound spatialization hardware). Furthermore, suppose there are Java3D audio device drivers that execute Java3D audio methods on each of these specific cards. In such a case the application would have at least two audio device drivers through which the audio could be produced. For such a case the Java3D application must choose the audio device driver with which sound rendering is to be performed. Once this audio device is chosen, the application can additionally select the type of audio playback type the rendered sound image is to be output on. The playback device (headphones or speaker(s)) is physically connected to the port the selected device driver outputs to.
AudioDevice Interface
- The selection of this device driver is done through methods in the
PhysicalEnvironment object - see PhysicalEnvironment class.
The application would query how many audio devices are available. For
each device, the user can get the AudioDevice object that describes it
and query its characteristics. Once a decision is made about which of
the available audio devices to use for a PhysicalEnvironment, the
particular device is set into this PhysicalEnvironment's fields. Each
PhysicalEnvironment object may use only a single audio device.
The AudioDevice object interface specifies an abstract input device that creators of Java3D class libraries would implement for a particular device. Java3D's uses several methods to interact with specific devices. Since all audio devices implement this consistent interface, the user could have a portable means of initialize, set particular audio device elements and query generic characteristics for any audio device.
Initialization
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Each audio device driver must be initialized.
The chosen device driver should be initialized before any Java3D
Sound methods are executed because the implementation of the Sound
methods, in general, are potentially device driver dependent.
Audio Playback Type
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These methods set and retrieve the audio playback type used to output
the analog audio from rendering Java3D Sound nodes.
The audio playback type specifies that playback will be through:
stereo headphones, a monaural speaker, or a pair of speakers.
For the stereo speakers, it is assumed that the two output speakers are
equally distant from the listener, both at same angle from the head
axis (thus oriented symmetrically about the listener), and at the same
elevation.
The type of playback chosen affects the sound image generated.
Cross-talk cancellation is applied to the audio image if playback over
stereo speakers is selected.
Distance to Speaker
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These methods set and retrieve the distance in meters from the center
ear (the midpoint between the left and right ears) and one of the
speakers in the listener's environment. For monaural speaker playback,
a typical distance from the listener to the speaker in a workstation
cabinet is 0.76 meters. For stereo speakers placed at the sides of the
display, this might be 0.82 meters.
Angular Offset of Speakers
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These methods set and retrieve the angle in radians between the vectors
from the center ear to each of the speaker transducers and the vectors
from the center ear parallel to the head coordinate's Z axis. Speakers
placed at the sides of the computer display typically range between
0.28 to 0.35 radians (between 10 and 20 degrees).
Device Driver Specific Data
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While the sound image created for final output to the playback system
is either only mono or stereo (for this version of Java3D) most device
driver implementations will mix the left and right image signals
generated for each rendered sound source before outputting the final
playback image. Each sound source will use N input channels of this
internal mixer. Each implemented Java3D audio device driver will have
its own limitations and driver-specific characteristics. These include
channel availability and usage (during rendering). Methods for
querying these device-driver specific characteristics are provided.
Instantiating and Registering a New Device
- A browser or applications developer must instantiate whatever system-
specific audio devices that he or she needs and that exist on the system.
This device information typically exists in a site configuration file.
The browser or application will instantiate the physical environment as
requested by the end-user.
The API for instantiating devices is site-specific, but it consists of a device object with a constructor and at least all of the methods specified in the AudioDevice interface.
Once instantiated, the browser or application must register the device with the Java3D sound scheduler by associating this device with a PhysicalEnvironment. The setAudioDevice method introduces new devices to the Java3D environment and the allAudioDevices method produces an enumeration that allows examining all available devices within a Java3D environment. See PhysicalEnvironment class for more details.
General Rules for calling AudioDevice methods: It is illegal for an application to call any non-query AudioDevice method if the AudioDevice is created then explicitly assigned to a PhysicalEnvironment using PhysicalEnvironment.setAudioDevice(); When either PhysicalEnvironment.setAudioDevice() is called - including when implicitly called by SimpleUniverse.getViewer().createAudioDevice() - the Core creates a SoundScheduler thread which makes calls to the AudioDevice.
If an application creates it's own instance of an AudioDevice and initializes it directly, rather than using PhysicalEnvironment. setAudioDevice(), that application may make any AudioDevice3D methods calls without fear of the Java 3D Core also trying to control the AudioDevice. Under this condition it is safe to call AudioDevice non-query methods.
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Field Summary
Fields Modifier and Type Field Description static int
HEADPHONES
Choosing Headphones as the audio playback type specifies that the audio playback will be through stereo headphones.static int
MONO_SPEAKER
Choosing a single near-field monoaural speaker as the audio playback type specifies that the audio playback will be through a single speaker some supplied distance away from the listener.static int
STEREO_SPEAKERS
Choosing a two near-field stereo speakers as the audio playback type specifies that the audio playback will be through stereo speakers some supplied distance away from, and at some given angle to the listener.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description boolean
close()
Code to close the device and release resources.float
getAngleOffsetToSpeaker()
Get Angle Offset (in radians) To Speaker.int
getAudioPlaybackType()
Get Type of Audio Playback Output Device.float
getCenterEarToSpeaker()
Get Distance from interaural mid-point between Ears to a Speaker.int
getChannelsAvailable()
Query number of channels currently available for use.int
getChannelsUsedForSound(Sound node)
Query number of channels that are used, or would be used to render a particular sound node.int
getTotalChannels()
Query total number of channels available for sound rendering for this audio device.boolean
initialize()
Initialize the audio device.void
setAngleOffsetToSpeaker(float angle)
Set Angle Offset (in radians) To Speaker.void
setAudioPlaybackType(int type)
Set Type of Audio Playback physical transducer(s) sound is output to.void
setCenterEarToSpeaker(float distance)
Set Distance from interaural mid-point between Ears to a Speaker.
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Field Detail
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HEADPHONES
static final int HEADPHONES
Choosing Headphones as the audio playback type specifies that the audio playback will be through stereo headphones.- See Also:
- Constant Field Values
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MONO_SPEAKER
static final int MONO_SPEAKER
Choosing a single near-field monoaural speaker as the audio playback type specifies that the audio playback will be through a single speaker some supplied distance away from the listener.- See Also:
- Constant Field Values
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STEREO_SPEAKERS
static final int STEREO_SPEAKERS
Choosing a two near-field stereo speakers as the audio playback type specifies that the audio playback will be through stereo speakers some supplied distance away from, and at some given angle to the listener.- See Also:
- Constant Field Values
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Method Detail
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initialize
boolean initialize()
Initialize the audio device. Exactly what occurs during initialization is implementation dependent. This method provides explicit control by the user over when this initialization occurs. Initialization must be initiated before any other AudioDevice methods are called.- Returns:
- true if initialization was successful without errors
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close
boolean close()
Code to close the device and release resources.- Returns:
- true if close of device was successful without errors
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setAudioPlaybackType
void setAudioPlaybackType(int type)
Set Type of Audio Playback physical transducer(s) sound is output to. Valid types are HEADPHONES, MONO_SPEAKER, STEREO_SPEAKERS- Parameters:
type
- audio playback type
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getAudioPlaybackType
int getAudioPlaybackType()
Get Type of Audio Playback Output Device.- Returns:
- audio playback type
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setCenterEarToSpeaker
void setCenterEarToSpeaker(float distance)
Set Distance from interaural mid-point between Ears to a Speaker.- Parameters:
distance
- from interaural midpoint between the ears to closest speaker
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getCenterEarToSpeaker
float getCenterEarToSpeaker()
Get Distance from interaural mid-point between Ears to a Speaker.- Returns:
- distance from interaural midpoint between the ears to closest speaker
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setAngleOffsetToSpeaker
void setAngleOffsetToSpeaker(float angle)
Set Angle Offset (in radians) To Speaker.- Parameters:
angle
- in radians from head Z axis and vector from center ear to speaker
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getAngleOffsetToSpeaker
float getAngleOffsetToSpeaker()
Get Angle Offset (in radians) To Speaker.- Returns:
- angle in radians from head Z axis and vector from center ear to speaker
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getTotalChannels
int getTotalChannels()
Query total number of channels available for sound rendering for this audio device. This returns the maximum number of channels available for Java3D sound rendering for all sound sources.- Returns:
- total number of channels that can be used for this audio device
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getChannelsAvailable
int getChannelsAvailable()
Query number of channels currently available for use. During rendering, when sound nodes are playing, this method returns the number of channels still available to Java3D for rendering additional sound nodes.- Returns:
- total number of channels current available
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getChannelsUsedForSound
int getChannelsUsedForSound(Sound node)
Query number of channels that are used, or would be used to render a particular sound node. This method returns the number of channels needed to render a particular Sound node. The return value is the same no matter if the Sound is currently active and enabled (being played) or is inactive.- Returns:
- number of channels a particular Sound node is using or would used if enabled and activated (rendered).
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