Package org.openni
Class VideoStream
java.lang.Object
org.openni.VideoStream
The
VideoStream
object encapsulates a single video stream from a device. Once created, it
is used to start data flow from the device, and to read individual frames of data. This is the
central class used to obtain data in OpenNI. It provides the ability to manually read data in a
polling loop, as well as providing events and a Listener class that can be used to implement
event-driven data acquisition.
Aside from the video data frames themselves, the class offers a number of functions used for
obtaining information about a VideoStream
. Field of view, available video modes, and
minimum and maximum valid pixel values can all be obtained.
In addition to obtaining data, the VideoStream
object is used to set all configuration
properties that apply to a specific stream (rather than to an entire device). In particular, it
is used to control cropping, mirroring, and video modes.
A valid, initialized device that provides the desired stream type is required to create a stream.
Several video streams can be created to stream data from the same sensor. This is useful if
several components of an application need to read frames separately.
While some device might allow different streams from the same sensor to have different
configurations, most devices will have a single configuration for the sensor, shared by all
streams.-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionclass
TheVideoStream.CameraSettings
object encapsulates camera setting for a single device.static interface
The VideoStream::NewFrameListener interface is provided to allow the implementation of event driven frame reading. -
Method Summary
Modifier and TypeMethodDescriptionvoid
addNewFrameListener
(VideoStream.NewFrameListener streamListener) Adds a new Listener to receive this VideoStream onNewFrame event.static VideoStream
create
(Device device, SensorType sensorType) Creates a stream of frames from a specific sensor type of a specific device.void
destroy()
Destroy this stream.Gets an object through which several camera settings can be configured.Obtains the current cropping settings for this stream.long
This function return stream handle.float
Gets the horizontal field of view of frames received from this stream.int
Provides the maximum possible value for pixels obtained by this stream.int
Provides the smallest possible value for pixels obtains by this VideoStream.boolean
Check whether mirroring is currently turned on for this stream.final SensorInfo
Provides theSensorInfo
object associated with the sensor that is producing thisVideoStream
.Gets the sensor type for this stream.float
Gets the vertical field of view of frames received from this stream.final VideoMode
Get the current video mode information for this video stream.boolean
Checks whether this stream supports cropping.Read the next frame from this video stream, delivered as aVideoFrameRef
.void
removeNewFrameListener
(VideoStream.NewFrameListener streamListener) Removes a Listener from this video stream list.void
Disables cropping.void
setCropping
(CropArea cropping) Changes the cropping settings for this stream.void
setMirroringEnabled
(boolean isEnabled) Enable or disable mirroring for this stream.void
setVideoMode
(VideoMode videoMode) Changes the current video mode of this stream.void
start()
Starts data generation from this video stream.void
stop()
Stops data generation from this video stream.
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Method Details
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create
Creates a stream of frames from a specific sensor type of a specific device. You must supply a reference to a Device that supplies the sensor type requested. You can useDevice.hasSensor(SensorType)
to check whether a given sensor is available on your target device before calling create().- Parameters:
device
- A reference to theDevice
you want to create the stream on.sensorType
- The type of sensor the stream should produce data from.
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destroy
public void destroy()Destroy this stream. This function is currently called automatically by the destructor, but it is considered a best practice for applications to manually call this function on anyVideoStream
that they call create() for. -
getSensorInfo
Provides theSensorInfo
object associated with the sensor that is producing thisVideoStream
.SensorInfo
is useful primarily as a means of learning which video modes are valid for this VideoStream.- Returns:
- SensorInfo object associated with the sensor providing this stream.
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start
public void start()Starts data generation from this video stream. -
stop
public void stop()Stops data generation from this video stream. -
readFrame
Read the next frame from this video stream, delivered as aVideoFrameRef
. This is the primary method for manually obtaining frames of video data. If no new frame is available, the call will block until one is available. To avoid blocking, useVideoStream.NewFrameListener
to implement an event driven architecture. Another alternative is to useOpenNI.waitForAnyStream(java.util.List, int)
to wait for new frames from several streams- Returns:
- VideoFrameRef object which hold the data of the new frame.
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addNewFrameListener
Adds a new Listener to receive this VideoStream onNewFrame event. SeeVideoStream.NewFrameListener
for more information on implementing an event driven frame reading architecture.- Parameters:
streamListener
- Object which implementsVideoStream.NewFrameListener
that will respond to this event.
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removeNewFrameListener
Removes a Listener from this video stream list. The listener removed will no longer receive new frame events from this stream.- Parameters:
streamListener
- Object of the listener to be removed.
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getHandle
public long getHandle()This function return stream handle.- Returns:
- OpenNI stream handle.
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getCameraSettings
Gets an object through which several camera settings can be configured.- Returns:
- null if the stream doesn't support camera settings.
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getVideoMode
Get the current video mode information for this video stream. This includes its resolution, fps and stream format.- Returns:
- Current video mode information for this video stream.
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setVideoMode
Changes the current video mode of this stream. Recommended practice is to useDevice.getSensorInfo(SensorType)
, and thenSensorInfo.getSupportedVideoModes()
to obtain a list of valid video mode settings for this stream. Then, pass a validVideoMode
to setVideoMode(VideoMode) to ensure correct operation.- Parameters:
videoMode
- Desired new video mode for this stream. returns Status code indicating success or failure of this operation.
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getMaxPixelValue
public int getMaxPixelValue()Provides the maximum possible value for pixels obtained by this stream. This is most useful for getting the maximum possible value of depth streams.- Returns:
- Maximum possible pixel value.
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getMinPixelValue
public int getMinPixelValue()Provides the smallest possible value for pixels obtains by this VideoStream. This is most useful for getting the minimum possible value that will be reported by a depth stream.- Returns:
- Minimum possible pixel value that can come from this stream.
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isCroppingSupported
public boolean isCroppingSupported()Checks whether this stream supports cropping.- Returns:
- true if the stream supports cropping, false if it does not.
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getCropping
Obtains the current cropping settings for this stream.- Returns:
- CropArea CropArea object which encapsulated cropping info.
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setCropping
Changes the cropping settings for this stream. You can use theisCroppingSupported()
function to make sure cropping is supported before calling this function.- Parameters:
cropping
- CropArea object which set corresponding cropping information.
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resetCropping
public void resetCropping()Disables cropping. -
getMirroringEnabled
public boolean getMirroringEnabled()Check whether mirroring is currently turned on for this stream.- Returns:
- true if mirroring is currently enabled, false otherwise.
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setMirroringEnabled
public void setMirroringEnabled(boolean isEnabled) Enable or disable mirroring for this stream.- Parameters:
isEnabled
- true to enable mirroring, false to disable it.
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getHorizontalFieldOfView
public float getHorizontalFieldOfView()Gets the horizontal field of view of frames received from this stream.- Returns:
- Horizontal field of view, in radians.
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getVerticalFieldOfView
public float getVerticalFieldOfView()Gets the vertical field of view of frames received from this stream.- Returns:
- Vertical field of view, in radians.
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getSensorType
Gets the sensor type for this stream.- Returns:
- sensor type.
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