/**
* Notifies this instance that a <tt>DatagramPacket</tt> packet received on the data
* <tt>DatagramSocket</tt> of this <tt>Channel</tt> has been accepted for further processing
* within Jitsi Videobridge.
*
* @param pkt the accepted <tt>RawPacket</tt>.
*/
public void accepted(RawPacket pkt) {
// With native simulcast we don't have a notification when a stream
// has started/stopped. The simulcast manager implements a timeout
// for the high quality stream and it needs to be notified when
// the channel has accepted a datagram packet for the timeout to
// function correctly.
if (!hasLayers() || pkt == null) {
return;
}
// Find the layer that corresponds to this packet.
int acceptedSSRC = pkt.getSSRC();
SimulcastLayer[] layers = getSimulcastLayers();
SimulcastLayer acceptedLayer = null;
for (SimulcastLayer layer : layers) {
// We only care about the primary SSRC and not the RTX ssrc (or
// future FEC ssrc).
if ((int) layer.getPrimarySSRC() == acceptedSSRC) {
acceptedLayer = layer;
break;
}
}
// If this is not an RTP packet or if we can't find an accepted
// layer, log and return as it makes no sense to continue in this
// situation.
if (acceptedLayer == null) {
return;
}
// There are sequences of packets with increasing timestamps but without
// the marker bit set. Supposedly, they are probes to detect whether the
// bandwidth may increase. We think that they should cause neither the
// start nor the stop of any SimulcastLayer.
// XXX There's RawPacket#getPayloadLength() but the implementation
// includes pkt.paddingSize at the time of this writing and we do not
// know whether that's going to stay that way.
int pktPayloadLength = pkt.getLength() - pkt.getHeaderLength();
int pktPaddingSize = pkt.getPaddingSize();
if (pktPayloadLength <= pktPaddingSize) {
if (logger.isTraceEnabled()) {
logger.trace(
"pkt.payloadLength= "
+ pktPayloadLength
+ " <= pkt.paddingSize= "
+ pktPaddingSize
+ "("
+ pkt.getSequenceNumber()
+ ")");
}
return;
}
// NOTE(gp) we expect the base layer to be always on, so we never touch
// it or starve it.
// XXX Refer to the implementation of
// SimulcastLayer#touch(boolean, RawPacket) for an explanation of why we
// chose to use a return value.
boolean frameStarted = acceptedLayer.touch(pkt);
if (frameStarted) simulcastLayerFrameStarted(acceptedLayer, pkt, layers);
}
