org.jitsi.impl.neomedia.transform.csrc

Class CsrcTransformEngine

java.lang.Object

org.jitsi.impl.neomedia.transform.SinglePacketTransformer

org.jitsi.impl.neomedia.transform.csrc.CsrcTransformEngine

All Implemented Interfaces:

PacketTransformer, TransformEngine

public class CsrcTransformEngine
extends SinglePacketTransformer
implements TransformEngine

We use this engine to add the list of CSRC identifiers in RTP packets that we send to conference participants during calls where we are the mixer.

Author:

Emil Ivov, Lyubomir Marinov

Constructor Summary

Constructors

Constructor and Description
CsrcTransformEngine(MediaStreamImpl mediaStream) Creates an engine instance that will be adding CSRC lists to the specified stream.

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	setCsrcAudioLevelExtensionID(byte extID, MediaDirection dir) Sets the ID that this transformer should be using for audio level extensions or disables audio level extensions if extID is -1.
RawPacket	transform(RawPacket pkt) Extracts the list of CSRC identifiers representing participants currently contributing to the media being sent by the MediaStream associated with this engine and (unless the list is empty) encodes them into the RawPacket.

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

Constructor Detail

CsrcTransformEngine

public CsrcTransformEngine(MediaStreamImpl mediaStream)

Creates an engine instance that will be adding CSRC lists to the specified stream.

Parameters:

mediaStream - that MediaStream whose RTP packets we are going to be adding CSRC lists. to

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 CsrcTransformEngine.

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.

Specified by:

reverseTransform in class SinglePacketTransformer

Parameters:

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

Returns:

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

setCsrcAudioLevelExtensionID

public void setCsrcAudioLevelExtensionID(byte extID,
                                         MediaDirection dir)

Sets the ID that this transformer should be using for audio level extensions or disables audio level extensions if extID is -1.

Parameters:

extID - ID that this transformer should be using for audio level extensions or -1 if audio level extensions should be disabled

dir - the direction that we are expected to hand this extension in.

transform

public RawPacket transform(RawPacket pkt)

Extracts the list of CSRC identifiers representing participants currently contributing to the media being sent by the MediaStream associated with this engine and (unless the list is empty) encodes them into the RawPacket.

Specified by:

transform in class SinglePacketTransformer

Parameters:

pkt - the RTP RawPacket that we need to add a CSRC list to.

Returns:

the updated RawPacket instance containing the list of CSRC identifiers.