org.jitsi.impl.neomedia.transform.csrc

Class SsrcTransformEngine

java.lang.Object

org.jitsi.impl.neomedia.transform.SinglePacketTransformer

org.jitsi.impl.neomedia.transform.SinglePacketTransformerAdapter

org.jitsi.impl.neomedia.transform.csrc.SsrcTransformEngine

All Implemented Interfaces:

PacketTransformer, TransformEngine

public class SsrcTransformEngine
extends SinglePacketTransformerAdapter
implements TransformEngine

Implements read-only support for "A Real-Time Transport Protocol (RTP) Header Extension for Client-to-Mixer Audio Level Indication". Optionally, drops RTP packets indicated to be generated from a muted audio source in order to avoid wasting processing power such as decrypting, decoding and audio mixing.

Author:

Emil Ivov, Lyubomir Marinov

Field Summary

Fields

Modifier and Type	Field and Description
static String	DROP_MUTED_AUDIO_SOURCE_IN_REVERSE_TRANSFORM The name of the ConfigurationService property which specifies whether SsrcTransformEngine is to drop RTP packets indicated as generated from a muted audio source in reverseTransform(RawPacket).

Constructor Summary

Constructors

Constructor and Description
SsrcTransformEngine(MediaStreamImpl mediaStream) Initializes a new SsrcTransformEngine to be utilized by a specific MediaStreamImpl.

Method Summary

Modifier and Type	Method and Description
void	close() Closes this PacketTransformer i.e.
PacketTransformer	getRTCPTransformer() Always returns null since this engine does not require any RTCP transformations.
PacketTransformer	getRTPTransformer() Returns a reference to this class since it is performing RTP transformations in here.
RawPacket	reverseTransform(RawPacket pkt) Extracts the list of CSRC identifiers and passes it to the MediaStream associated with this engine.
void	setSsrcAudioLevelExtensionID(byte extID, MediaDirection dir)

Methods inherited from class org.jitsi.impl.neomedia.transform.SinglePacketTransformerAdapter

transform

Methods inherited from class org.jitsi.impl.neomedia.transform.SinglePacketTransformer

reverseTransform, transform

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DROP_MUTED_AUDIO_SOURCE_IN_REVERSE_TRANSFORM

public static final String DROP_MUTED_AUDIO_SOURCE_IN_REVERSE_TRANSFORM

The name of the ConfigurationService property which specifies whether SsrcTransformEngine is to drop RTP packets indicated as generated from a muted audio source in reverseTransform(RawPacket).

Constructor Detail

SsrcTransformEngine

public SsrcTransformEngine(MediaStreamImpl mediaStream)

Initializes a new SsrcTransformEngine to be utilized by a specific MediaStreamImpl.

Parameters:

mediaStream - the MediaStreamImpl to utilize the new instance

Method Detail

close

public void close()

Closes this PacketTransformer i.e. releases the resources allocated by it and prepares it for garbage collection.

Specified by:

close in interface PacketTransformer

Overrides:

close in class SinglePacketTransformer

getRTCPTransformer

public PacketTransformer getRTCPTransformer()

Always returns null since this engine does not require any RTCP transformations.

Specified by:

getRTCPTransformer in interface TransformEngine

Returns:

null since this engine does not require any RTCP transformations.

getRTPTransformer

public PacketTransformer getRTPTransformer()

Returns a reference to this class since it is performing RTP transformations in here.

Specified by:

getRTPTransformer in interface TransformEngine

Returns:

a reference to this instance of the SsrcTransformEngine.

reverseTransform

public RawPacket reverseTransform(RawPacket pkt)

Extracts the list of CSRC identifiers and passes it to the MediaStream associated with this engine. Other than that the method does not do any transformations since CSRC lists are part of RFC 3550 and they shouldn't be disrupting the rest of the application.

Overrides:

reverseTransform in class SinglePacketTransformerAdapter

Parameters:

pkt - the RTP RawPacket that we are to extract a SSRC list from.

Returns:

the same RawPacket that was received as a parameter since we don't need to worry about hiding the SSRC list from the rest of the RTP stack.

setSsrcAudioLevelExtensionID

public void setSsrcAudioLevelExtensionID(byte extID,
                                         MediaDirection dir)