private MediaFormat[] getEncodings() {
if (encodings != null) return encodings;
MediaFormat[] availableEncodings = encodingConfiguration.getAllEncodings(type);
int encodingCount = availableEncodings.length;
if (encodingCount < 1) encodings = MediaUtils.EMPTY_MEDIA_FORMATS;
else {
/*
* The MediaFormats will be displayed by encoding (name) and clock
* rate and EncodingConfiguration will store them that way so this
* TableModel should better display unique encoding-clock rate
* pairs.
*/
HashMap<String, MediaFormat> availableEncodingSet = new HashMap<String, MediaFormat>();
for (MediaFormat availableEncoding : availableEncodings) {
availableEncodingSet.put(
availableEncoding.getEncoding() + "/" + availableEncoding.getClockRateString(),
availableEncoding);
}
availableEncodings = availableEncodingSet.values().toArray(MediaUtils.EMPTY_MEDIA_FORMATS);
encodingCount = availableEncodings.length;
encodings = new MediaFormat[encodingCount];
System.arraycopy(availableEncodings, 0, encodings, 0, encodingCount);
// Display the encodings in decreasing priority.
Arrays.sort(
encodings,
0,
encodingCount,
new Comparator<MediaFormat>() {
public int compare(MediaFormat format0, MediaFormat format1) {
int ret =
encodingConfiguration.getPriority(format1)
- encodingConfiguration.getPriority(format0);
if (ret == 0) {
/*
* In the cases of equal priorities, display them
* sorted by encoding name in increasing order.
*/
ret = format0.getEncoding().compareToIgnoreCase(format1.getEncoding());
if (ret == 0) {
/*
* In the cases of equal priorities and equal
* encoding names, display them sorted by clock
* rate in decreasing order.
*/
ret = Double.compare(format1.getClockRate(), format0.getClockRate());
}
}
return ret;
}
});
}
return encodings;
}
/**
* Encapsulates {@code pkt} in the RTX format, using {@code rtxSsrc} as its SSRC, and transmits it
* to {@link #channel} by injecting it in the {@code MediaStream}.
*
* @param pkt the packet to transmit.
* @param rtxSsrc the SSRC for the RTX stream.
* @param after the {@code TransformEngine} in the chain of {@code TransformEngine}s of the
* associated {@code MediaStream} after which the injection of {@code pkt} is to begin
* @return {@code true} if the packet was successfully retransmitted, {@code false} otherwise.
*/
private boolean encapsulateInRtxAndTransmit(RawPacket pkt, long rtxSsrc, TransformEngine after) {
byte[] buf = pkt.getBuffer();
int len = pkt.getLength();
int off = pkt.getOffset();
byte[] newBuf = new byte[len + 2];
RawPacket rtxPkt = new RawPacket(newBuf, 0, len + 2);
int osn = pkt.getSequenceNumber();
int headerLength = pkt.getHeaderLength();
int payloadLength = pkt.getPayloadLength();
// Copy the header.
System.arraycopy(buf, off, newBuf, 0, headerLength);
// Set the OSN field.
newBuf[headerLength] = (byte) ((osn >> 8) & 0xff);
newBuf[headerLength + 1] = (byte) (osn & 0xff);
// Copy the payload.
System.arraycopy(buf, off + headerLength, newBuf, headerLength + 2, payloadLength);
MediaStream mediaStream = channel.getStream();
if (mediaStream != null) {
rtxPkt.setSSRC((int) rtxSsrc);
rtxPkt.setPayloadType(rtxPayloadType);
// Only call getNextRtxSequenceNumber() when we're sure we're going
// to transmit a packet, because it consumes a sequence number.
rtxPkt.setSequenceNumber(getNextRtxSequenceNumber(rtxSsrc));
try {
mediaStream.injectPacket(rtxPkt, /* data */ true, after);
} catch (TransmissionFailedException tfe) {
logger.warn("Failed to transmit an RTX packet.");
return false;
}
}
return true;
}
/**
* 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;
}
