org.jitsi.impl.neomedia.transform.pt

Class PayloadTypeTransformEngine

java.lang.Object

org.jitsi.impl.neomedia.transform.SinglePacketTransformer

org.jitsi.impl.neomedia.transform.SinglePacketTransformerAdapter

org.jitsi.impl.neomedia.transform.pt.PayloadTypeTransformEngine

All Implemented Interfaces:

PacketTransformer, TransformEngine

public class PayloadTypeTransformEngine
extends SinglePacketTransformerAdapter
implements TransformEngine

We use this engine to change payload types of outgoing RTP packets if needed. This is necessary so that we can support the RFC3264 case where the answerer has the right to declare what payload type mappings it wants to receive even if they are different from those in the offer. RFC3264 claims this is for support of legacy protocols such as H.323 but we've been bumping with a number of cases where multi-component pure SIP systems also need to behave this way.

Author:

Damian Minkov

Constructor Summary

Constructors

Constructor and Description
PayloadTypeTransformEngine()

Method Summary

Modifier and Type	Method and Description
void	addPTMappingOverride(byte originalPt, byte overridePt) Adds an additional RTP payload type mapping used to override the payload type of outgoing RTP packets.
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	transform(RawPacket pkt) Checks if there are any override mappings, if no setting just pass through the packet.

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

reverseTransform

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

PayloadTypeTransformEngine

public PayloadTypeTransformEngine()

Method Detail

transform

public RawPacket transform(RawPacket pkt)

Checks if there are any override mappings, if no setting just pass through the packet. If the RawPacket payload has entry in mappings to override, we override packet payload type.

Overrides:

transform in class SinglePacketTransformerAdapter

Parameters:

pkt - the RTP RawPacket that we check for need to change payload type.

Returns:

the updated RawPacket instance containing the changed payload type.

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

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 PayloadTypeTransformEngine.

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.

addPTMappingOverride

public void addPTMappingOverride(byte originalPt,
                                 byte overridePt)

Adds an additional RTP payload type mapping used to override the payload type of outgoing RTP packets. If an override for originalPT, was already being overridden, this call is simply going to update the override to the new one.

This method creates a copy of the local overriding map so that mapping overrides could be set during a call (e.g. after a SIP re-INVITE) in a thread-safe way without using synchronization.

Parameters:

originalPt - the payload type that we are overriding

overridePt - the payload type that we are overriding it with