/**
* Updates this <tt>RTPStatsMap</tt> with information it gets from the <tt>RawPacket</tt>.
*
* @param pkt the <tt>RawPacket</tt> that is being transmitted.
*/
public void apply(RawPacket pkt) {
int ssrc = pkt.getSSRC();
if (this.containsKey(ssrc)) {
RTPStatsEntry oldRtpStatsEntry = this.get(ssrc);
// Replace whatever was in there before. A feature of the two's
// complement encoding (which is used by Java integers) is that
// the bitwise results for add, subtract, and multiply are the
// same if both inputs are interpreted as signed values or both
// inputs are interpreted as unsigned values. (Other encodings
// like one's complement and signed magnitude don't have this
// properly.)
this.put(
ssrc,
new RTPStatsEntry(
ssrc,
oldRtpStatsEntry.getBytesSent()
+ pkt.getLength()
- pkt.getHeaderLength()
- pkt.getPaddingSize(),
oldRtpStatsEntry.getPacketsSent() + 1));
} else {
// Add a new <tt>RTPStatsEntry</tt> in this map.
this.put(
ssrc,
new RTPStatsEntry(
ssrc, pkt.getLength() - pkt.getHeaderLength() - pkt.getPaddingSize(), 1));
}
}
/**
* Removes the RTX encapsulation from a packet.
*
* @param pkt the packet to remove the RTX encapsulation from.
* @return the original media packet represented by {@code pkt}, or null if we couldn't
* reconstruct the original packet.
*/
private RawPacket deRtx(RawPacket pkt) {
boolean success = false;
if (pkt.getPayloadLength() - pkt.getPaddingSize() < 2) {
// We need at least 2 bytes to read the OSN field.
if (logger.isDebugEnabled()) {
logger.debug("Dropping an incoming RTX packet with padding only: " + pkt);
}
return null;
}
long mediaSsrc = getPrimarySsrc(pkt);
if (mediaSsrc != -1) {
if (rtxAssociatedPayloadType != -1) {
int osn = pkt.getOriginalSequenceNumber();
// Remove the RTX header by moving the RTP header two bytes
// right.
byte[] buf = pkt.getBuffer();
int off = pkt.getOffset();
System.arraycopy(buf, off, buf, off + 2, pkt.getHeaderLength());
pkt.setOffset(off + 2);
pkt.setLength(pkt.getLength() - 2);
pkt.setSSRC((int) mediaSsrc);
pkt.setSequenceNumber(osn);
pkt.setPayloadType(rtxAssociatedPayloadType);
success = true;
} else {
logger.warn(
"RTX packet received, but no APT is defined. Packet "
+ "SSRC "
+ pkt.getSSRCAsLong()
+ ", associated media"
+ " SSRC "
+ mediaSsrc);
}
}
// If we failed to handle the RTX packet, drop it.
return success ? pkt : null;
}
/**
* 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);
}
