org.gstreamer.event
Class QOSEvent

java.lang.Object
  extended by org.gstreamer.lowlevel.NativeValue
      extended by org.gstreamer.lowlevel.Handle
          extended by org.gstreamer.lowlevel.NativeObject
              extended by org.gstreamer.lowlevel.RefCountedObject
                  extended by org.gstreamer.MiniObject
                      extended by org.gstreamer.Event
                          extended by org.gstreamer.event.QOSEvent

public class QOSEvent
extends Event

A quality message. Used to indicate to upstream elements that the downstream elements are being starved of or flooded with data.

The QOS event is generated in an element that wants an upstream element to either reduce or increase its rate because of high/low CPU load or other resource usage such as network performance. Typically sinks generate these events for each buffer they receive.


Nested Class Summary
 
Nested classes/interfaces inherited from class org.gstreamer.lowlevel.NativeObject
NativeObject.Initializer
 
Field Summary
 
Fields inherited from class org.gstreamer.lowlevel.NativeObject
defaultInit, LIFECYCLE, ownsHandle
 
Constructor Summary
QOSEvent(double proportion, long difference, ClockTime timestamp)
          Creates a new quality-of-service event.
QOSEvent(NativeObject.Initializer init)
          This constructor is for internal use only.
 
Method Summary
 long getDifference()
          Gets the difference value of this event.
 double getProportion()
          Gets the proportion value of this event.
 ClockTime getTimestamp()
          Gets the timestamp from this event.
 
Methods inherited from class org.gstreamer.Event
getStructure
 
Methods inherited from class org.gstreamer.MiniObject
disposeNativeHandle, isWritable, makeWritable, objectFor, ref, unref
 
Methods inherited from class org.gstreamer.lowlevel.NativeObject
classFor, disown, dispose, equals, finalize, getNativeAddress, handle, hashCode, initializer, initializer, instanceFor, invalidate, isDisposed, nativeValue, objectFor, objectFor, toString
 
Methods inherited from class java.lang.Object
clone, getClass, notify, notifyAll, wait, wait, wait
 

Constructor Detail

QOSEvent

public QOSEvent(NativeObject.Initializer init)
This constructor is for internal use only.

Parameters:
init - initialization data.

QOSEvent

public QOSEvent(double proportion,
                long difference,
                ClockTime timestamp)
Creates a new quality-of-service event.

proportion indicates the real-time performance of the streaming in the element that generated the QoS event (usually the sink). The value is generally computed based on more long term statistics about the streams timestamps compared to the clock.

A value < 1.0 indicates that the upstream element is producing data faster than real-time. A value > 1.0 indicates that the upstream element is not producing data fast enough. 1.0 is the ideal proportion value. The proportion value can safely be used to lower or increase the quality of the element.

difference is the difference against the clock in running time of the last buffer that caused the element to generate the QOS event. A negative value means that the buffer with timestamp arrived in time. A positive value indicates how late the buffer with timestamp was.

timestamp is the timestamp of the last buffer that cause the element to generate the QOS event. It is expressed in running time and thus an ever increasing value.

The upstream element can use the diff and timestamp values to decide whether to process more buffers. For positive difference, all buffers with timestamp <= timestamp + difference will certainly arrive late in the sink as well.

The application can use general event probes to intercept the QoS event and implement custom application specific QoS handling.

Parameters:
proportion - the proportion of the qos message
difference - the time difference of the last Clock sync
timestamp - the timestamp of the buffer
Method Detail

getProportion

public double getProportion()
Gets the proportion value of this event.

The proportion indicates the real-time performance of the streaming in the element that generated the QoS event (usually the sink). The value is generally computed based on more long term statistics about the streams timestamps compared to the clock.

Returns:
the proportion.

getDifference

public long getDifference()
Gets the difference value of this event.

This is the difference against the clock in running time of the last buffer that caused the element to generate the QOS event. A negative value means that the buffer with timestamp arrived in time. A positive value indicates how late the buffer with timestamp was.

Returns:
the difference.

getTimestamp

public ClockTime getTimestamp()
Gets the timestamp from this event.

This is the timestamp of the last buffer that caused the element to generate the QOS event. It is expressed in running time and thus an ever increasing value.

Returns:
the timestamp