internal float RecentPacketLoss => Math.Min(_recentPacketLoss.Output, 1); // 0..1
void OnPlayed(JitterBufferElement jbe, uint timeNow32)
{
if (_lastPlayedJBE != null)
{
var missingPacketsCountAtThisPlaybackTime = SubtractSequences(jbe.sequence, _lastPlayedJBE.sequence) - 1;
// var timePassed32AtSender = SubtractTimestamps(jbe.timestamp32, _lastPlayedJBE.timestamp32);////todo better use local time
// if (missingPacketsCountAtThisPlaybackTime > 100)
// _subtLocalPeer.WriteToLog($"missingPacketsCountAtThisPlaybackTime = {missingPacketsCountAtThisPlaybackTime}");
_recentPacketLoss.Input(missingPacketsCountAtThisPlaybackTime
// , timePassed32AtSender
);
_recentPacketLoss.OnTimeObserved(timeNow32);
lock (_recentBandwidth)
{
_recentBandwidth.Input(jbe.bandwidthSizeBits//, timePassed32
);
_recentBandwidth.OnTimeObserved(timeNow32);
}
}
_lastPlayedJBE = jbe;
}
/// <summary>
/// general algorithm:
/// find a place where to insert this packet into jitter buffer
/// if it is duplicate, ignore the packet
/// insert into jitter buffer
/// simulate playback: remove elements from head of the JB
/// calculate packet loss out of sequence fields
/// </summary>
internal void OnReceivedPacket(ushort bandwidthSizeBits, ushort sequence, uint timestamp32, uint timeNow32)
{
var jbe = new JitterBufferElement { timestamp32 = timestamp32, sequence = sequence, bandwidthSizeBits = bandwidthSizeBits };
if (TryInsertIntoJitterBuffer(jbe))
{
PlaybackFromJitter(timeNow32);
}
}
bool TryInsertIntoJitterBuffer(JitterBufferElement jbe)
{
// _subtLocalPeer.WriteToLog($">> TryInsertIntoJitterBuffer strm{_stream.StreamId} count={_jitterBuffer.Count} ts={jbe.timestamp32} seq={jbe.sequence} last (newest) TS={_jitterBuffer.Last?.Value?.timestamp32}");
if (IsNewElementOutOfSequence(jbe)) return false;
LinkedListNode<JitterBufferElement> insertAfter = null;
for (var item = _jitterBuffer.Last; ;)
{
if (item == null) break;
var enumeratedSequence = item.Value.sequence;
if (enumeratedSequence == jbe.sequence) return false; // duplicate packet
if (Sequence1IsLess(enumeratedSequence, jbe.sequence))
{
insertAfter = item;
break;
}
item = item.Previous;
}
if (insertAfter == null)
{
//if (_jitterBuffer.First != null)
//{
// if (TimeStamp1IsLess(_jitterBuffer.First.Value.timestamp32, jbe.timestamp32))
// {
// // throw new Exception();
// _subtLocalPeer.WriteToLog($"strm{_stream.StreamId} count={_jitterBuffer.Count}. bad item put into JB: ts={jbe.timestamp32} seq={jbe.sequence} firstTS={_jitterBuffer.First.Value.timestamp32} firstSeq={_jitterBuffer.First.Value.sequence} ");
// foreach (var item in _jitterBuffer)
// _subtLocalPeer.WriteToLog($"strm{_stream.StreamId} item: TS={item.timestamp32} seq={item.sequence} ");
// return false;
// }
//}
_jitterBuffer.AddFirst(jbe);
}
else
{
if (MiscProcedures.TimeStamp1IsLess(jbe.timestamp32, insertAfter.Value.timestamp32))
{
_subtLocalPeer.WriteToLog_lightPain($"JB corruption check: received {jbe}; first: {_jitterBuffer.First?.Value}; last: {_jitterBuffer.Last?.Value}");
return false;
//throw new Exception();
}
_jitterBuffer.AddAfter(insertAfter, jbe);
}
// if (_stream.Stream.Debug)
// CheckJitterBuffer();
return true;
}
bool IsNewElementOutOfSequence(JitterBufferElement jbe)
{
if (_jitterBuffer.Count != 0)
{
var firstSeq = _jitterBuffer.First.Value.sequence;
var lastSeq = _jitterBuffer.Last.Value.sequence;
const ushort maxDistance = 1000; // TODO why 1000??
var minSequence = unchecked((ushort)(firstSeq - maxDistance));
if (Sequence1IsLess(jbe.sequence, minSequence)) return true;
var maxSequence = unchecked((ushort)(lastSeq + maxDistance));
if (Sequence1IsLess(maxSequence, jbe.sequence)) return true;
return false;
}
return false;
}
