org.jitsi.impl.neomedia.transform.fec

Class AbstractFECReceiver

java.lang.Object

org.jitsi.impl.neomedia.transform.fec.AbstractFECReceiver

All Implemented Interfaces:

PacketTransformer

Direct Known Subclasses:

FlexFec03Receiver, ULPFECReceiver

public abstract class AbstractFECReceiver
extends Object
implements PacketTransformer

A PacketTransformer which handles incoming fec packets. This class contains only the generic fec handling logic.

Author:

bgrozev, bbaldino

Field Summary

Fields

Modifier and Type	Field and Description
protected SortedMap<Integer,RawPacket>	fecPackets Buffer which keeps (copies of) received fec packets.
protected boolean	handleFec Allow disabling of handling of ulpfec packets for testing purposes.
protected SortedMap<Integer,RawPacket>	mediaPackets Buffer which keeps (copies of) received media packets.
protected long	ssrc The SSRC of the fec stream NOTE that for ulpfec this might be the same as the associated media stream, whereas for flexfec it will be different
protected org.jitsi.impl.neomedia.transform.fec.AbstractFECReceiver.Statistics	statistics Statistics for this fec receiver

Method Summary

Modifier and Type	Method and Description
void	close() Closes this PacketTransformer i.e.
protected abstract RawPacket[]	doReverseTransform(RawPacket[] pkts) Perform fec receive logic specific to the fec implementation
RawPacket[]	reverseTransform(RawPacket[] pkts) Reverse-transforms each packet in an array of packets.
protected void	saveMedia(RawPacket p) Makes a copy of p into mediaPackets.
void	setPayloadType(byte payloadType) Sets the ulpfec payload type.
RawPacket[]	transform(RawPacket[] pkts) Transforms each packet in an array of packets.

Methods inherited from class java.lang.Object

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

Field Detail

statistics

protected final org.jitsi.impl.neomedia.transform.fec.AbstractFECReceiver.Statistics statistics

Statistics for this fec receiver

ssrc

protected long ssrc

The SSRC of the fec stream NOTE that for ulpfec this might be the same as the associated media stream, whereas for flexfec it will be different

handleFec

protected boolean handleFec

Allow disabling of handling of ulpfec packets for testing purposes.

mediaPackets

protected final SortedMap<Integer,RawPacket> mediaPackets

Buffer which keeps (copies of) received media packets. We keep them ordered by their RTP sequence numbers, so that we can easily select the oldest one to discard when the buffer is full (when the map has more than MEDIA_BUFF_SIZE entries). We keep them in a Map so that we can easily search for a packet with a specific sequence number. Note: This might turn out to be inefficient, especially with increased buffer sizes. In the vast majority of cases (e.g. on every received packet) we do an insert at one end and a delete from the other -- this can be optimized. We very rarely (when we receive a packet out of order) need to insert at an arbitrary location. FIXME: Look at using the existing packet cache instead of our own here

fecPackets

protected final SortedMap<Integer,RawPacket> fecPackets

Buffer which keeps (copies of) received fec packets. We keep them ordered by their RTP sequence numbers, so that we can easily select the oldest one to discard when the buffer is full (when the map has more than FEC_BUFF_SIZE entries. We keep them in a Map so that we can easily search for a packet with a specific sequence number. Note: This might turn out to be inefficient, especially with increased buffer sizes. In the vast majority of cases (e.g. on every received packet) we do an insert at one end and a delete from the other -- this can be optimized. We very rarely (when we receive a packet out of order) need to insert at an arbitrary location. FIXME: Look at using the existing packet cache instead of our own here

Method Detail

saveMedia

protected void saveMedia(RawPacket p)

Makes a copy of p into mediaPackets. If the size of mediaPackets has reached MEDIA_BUFF_SIZE discards the oldest packet from it and reuses it.

Parameters:

p - the packet to copy.

setPayloadType

public void setPayloadType(byte payloadType)

Sets the ulpfec payload type.

Parameters:

payloadType - the payload type. FIXME(brian): do we need both this and the ability to pass the payload type in the ctor? Can we get rid of this or get rid of the arg in the ctor?

transform

public RawPacket[] transform(RawPacket[] pkts)

Transforms each packet in an array of packets. Null values must be ignored. Don't touch "outgoing".

Specified by:

transform in interface PacketTransformer

Parameters:

pkts - the packets to be transformed

Returns:

the transformed packets

reverseTransform

public RawPacket[] reverseTransform(RawPacket[] pkts)

Description copied from interface: PacketTransformer

Reverse-transforms each packet in an array of packets. Null values must be ignored.

Specified by:

reverseTransform in interface PacketTransformer

Parameters:

pkts - the transformed packets to be restored.

Returns:

the restored packets.

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

doReverseTransform

protected abstract RawPacket[] doReverseTransform(RawPacket[] pkts)

Perform fec receive logic specific to the fec implementation

Parameters:

pkts - the input media packets

Returns:

a RawPacket[] containing the given media packets as well as any media packets that were recovered