/**
* Gets the <tt>MediaFormat</tt>s among the specified <tt>mediaFormats</tt> which have the
* specified <tt>encoding</tt> and, optionally, <tt>clockRate</tt>.
*
* @param mediaFormats the <tt>MediaFormat</tt>s from which to filter out only the ones which have
* the specified <tt>encoding</tt> and, optionally, <tt>clockRate</tt>
* @param encoding the well-known encoding (name) of the <tt>MediaFormat</tt>s to be retrieved
* @param clockRate the clock rate of the <tt>MediaFormat</tt>s to be retrieved; {@link
* #CLOCK_RATE_NOT_SPECIFIED} if any clock rate is acceptable
* @return a <tt>List</tt> of the <tt>MediaFormat</tt>s among <tt>mediaFormats</tt> which have the
* specified <tt>encoding</tt> and, optionally, <tt>clockRate</tt>
*/
private List<MediaFormat> getMatchingMediaFormats(
MediaFormat[] mediaFormats, String encoding, double clockRate) {
/*
* XXX Use String#equalsIgnoreCase(String) because some clients transmit
* some of the codecs starting with capital letters.
*/
/*
* As per RFC 3551.4.5.2, because of a mistake in RFC 1890 and for
* backward compatibility, G.722 should always be announced as 8000 even
* though it is wideband. So, if someone is looking for G722/16000,
* then: Forgive them, for they know not what they do!
*/
if ("G722".equalsIgnoreCase(encoding) && (16000 == clockRate)) {
clockRate = 8000;
if (logger.isInfoEnabled()) logger.info("Suppressing erroneous 16000 announcement for G.722");
}
List<MediaFormat> supportedMediaFormats = new ArrayList<MediaFormat>();
for (MediaFormat mediaFormat : mediaFormats) {
if (mediaFormat.getEncoding().equalsIgnoreCase(encoding)
&& ((CLOCK_RATE_NOT_SPECIFIED == clockRate)
|| (mediaFormat.getClockRate() == clockRate))) {
supportedMediaFormats.add(mediaFormat);
}
}
return supportedMediaFormats;
}
/**
* Notifies this {@code SimulcastReceiver} that a specific {@code SimulcastReceiver} has detected
* the start of a new video frame in the RTP stream that it represents. Determines whether any of
* {@link #simulcastLayers} other than {@code source} have been paused/stopped by the remote peer.
* The determination is based on counting (video) frames.
*
* @param source the {@code SimulcastLayer} which is the source of the event i.e. which has
* detected the start of a new video frame in the RTP stream that it represents
* @param pkt the {@code RawPacket} which was received by {@code source} and possibly influenced
* the decision that a new view frame was started in the RTP stream represented by {@code
* source}
* @param layers the set of {@code SimulcastLayer}s managed by this {@code SimulcastReceiver}.
* Explicitly provided to the method in order to avoid invocations of {@link
* #getSimulcastLayers()} because the latter makes a copy at the time of this writing.
*/
private void simulcastLayerFrameStarted(
SimulcastLayer source, RawPacket pkt, SimulcastLayer[] layers) {
// Allow the value of the constant TIMEOUT_ON_FRAME_COUNT to disable (at
// compile time) the frame-based approach to the detection of layer
// drops.
if (TIMEOUT_ON_FRAME_COUNT <= 1) return;
// Timeouts in layers caused by source may occur only based on the span
// (of time or received frames) during which source has received
// TIMEOUT_ON_FRAME_COUNT number of frames. The current method
// invocation signals the receipt of 1 frame by source.
int indexOfLastSourceOccurrenceInHistory = -1;
int sourceFrameCount = 0;
int ix = 0;
for (Iterator<SimulcastLayer> it = simulcastLayerFrameHistory.iterator(); it.hasNext(); ++ix) {
if (it.next() == source) {
if (indexOfLastSourceOccurrenceInHistory != -1) {
// Prune simulcastLayerFrameHistory so that it does not
// become unnecessarily long.
it.remove();
} else if (++sourceFrameCount >= TIMEOUT_ON_FRAME_COUNT - 1) {
// The span of TIMEOUT_ON_FRAME_COUNT number of frames
// received by source only is to be examined for the
// purposes of timeouts. The current method invocations
// signals the receipt of 1 frame by source so
// TIMEOUT_ON_FRAME_COUNT - 1 occurrences of source in
// simulcastLayerFrameHistory is enough.
indexOfLastSourceOccurrenceInHistory = ix;
}
}
}
if (indexOfLastSourceOccurrenceInHistory != -1) {
// Presumably, if a SimulcastLayer is active, all SimulcastLayers
// before it (according to SimulcastLayer's order) are active as
// well. Consequently, timeouts may occur in SimulcastLayers which
// are after source.
boolean maybeTimeout = false;
for (SimulcastLayer layer : layers) {
if (maybeTimeout) {
// There's no point in timing layer out if it's timed out
// already.
if (layer.isStreaming()) {
maybeTimeout(source, pkt, layer, indexOfLastSourceOccurrenceInHistory);
}
} else if (layer == source) {
maybeTimeout = true;
}
}
}
// As previously stated, the current method invocation signals the
// receipt of 1 frame by source.
simulcastLayerFrameHistory.add(0, source);
// TODO Prune simulcastLayerFrameHistory by forgetting so that it does
// not become too long.
}
/**
* Adds <tt>WebRtcDataStreamListener</tt> to the list of listeners.
*
* @param listener the <tt>WebRtcDataStreamListener</tt> to be added to the listeners list.
*/
public void addChannelListener(WebRtcDataStreamListener listener) {
if (listener == null) {
throw new NullPointerException("listener");
} else {
synchronized (listeners) {
if (!listeners.contains(listener)) {
listeners.add(listener);
}
}
}
}
