/// <summary>
/// Tries to retrieve the next available ALAC frame
/// </summary>
/// <param name="frame">Will be set to the retrieved frame if successful</param>
/// <returns>True if successful, False if waiting for next frame and null if the audio buffer has been stopped</returns>
public bool?GetNextFrame(out byte[] frame, out uint timeStamp)
{
frame = null;
timeStamp = 0;
if (bufferStopped)
{
return(null);
}
lock (syncRoot)
{
if (bufferStopped)
{
return(null);
}
if (!bufferInit || actualBufferSize < 1 || !synced)
{
if (synced && actualBufferSize < 1)
{
//Buffer underrun
Logger.Warn("Audio Buffer: Underrun");
}
// Signal we're waiting and wait for next packet
Logger.Debug("Audio Buffer: Waiting for new packet");
decoderStopped = true;
Monitor.Wait(syncRoot);
if (bufferStopped)
{
return(null);
}
Logger.Debug("Audio Buffer: New packet received");
decoderStopped = false;
OnBufferRestart();
}
// Overrunning. Restart at a sane distance
if (actualBufferSize >= maxBufferFrames)
{
Logger.Debug("Buffer overrun");
readIndex = (ushort)(writeIndex - startFill);
}
for (int i = 16; i < (startFill / 2); i = i * 2)
{
int next = readIndex + i;
if (!audioBuffer[next % maxBufferFrames].Ready)
{
OnMissingPackets(new MissingPacketEventArgs(next, next + 1));
}
}
AudioData buffer = audioBuffer[readIndex % maxBufferFrames];
bool ready = buffer.Ready;
if (ready)
{
timeStamp = buffer.TimeStamp;
frame = ProcessNextPacket(buffer.Data);
buffer.Ready = false;
}
else
{
//Logger.Warn("Audio Buffer: Missing packet {0}", readIndex);
}
readIndex++;
actualBufferSize = (ushort)(writeIndex - readIndex);
OnPacketTaken();
return(ready);
}
}
/// <summary>
/// Decrypts and adds the audio data to the buffer
/// </summary>
/// <param name="seqno">The sequence number of the packet</param>
/// <param name="timestamp">The timestamp of the packet</param>
/// <param name="data">The encrypted audio packet</param>
public void PutPacketInBuffer(ushort seqno, uint timestamp, byte[] data)
{
if (bufferStopped)
{
return;
}
bool fireStarted = false;
bool fireReady = false;
lock (syncRoot)
{
if (bufferStopped)
{
return;
}
if (!synced)
{
writeIndex = seqno;
readIndex = seqno;
synced = true;
}
AudioData buffer = audioBuffer[seqno % maxBufferFrames];
if (seqno == writeIndex)
{
//Packet we expected
buffer.Data = data;
buffer.TimeStamp = timestamp;
buffer.Ready = true;
writeIndex++;
}
else if (isSequence(writeIndex, seqno))
{
//Too early, missed packets between writeIndex and seqno
//Logger.Debug("Audio Buffer: Received packet early. Expected: {0}, Received: {1}", writeIndex, seqno);
//OnMissingPackets(new MissingPacketEventArgs(writeIndex, seqno)); //ask to resend
buffer.Data = data;
buffer.TimeStamp = timestamp;
buffer.Ready = true;
//jump to new seq no.
writeIndex = (ushort)(seqno + 1);
}
else if (isSequence(readIndex, seqno))
{
//Less than write index but greater than read so not yet played, insert
//Logger.Debug("Audio Buffer: Received packet late but still in time to play. Expected: {0}, Received: {1}", writeIndex, seqno);
buffer.Data = data;
buffer.TimeStamp = timestamp;
buffer.Ready = true;
return;
}
else
{
//Already played
Logger.Warn("Audio Buffer: Received packet late. Expected: {0}, Received: {1}", writeIndex, seqno);
return;
}
// The number of packets in buffer
actualBufferSize = (ushort)(writeIndex - readIndex);
if (!bufferStarted && actualBufferSize > 0)
{
bufferStarted = true;
fireStarted = true;
}
if (actualBufferSize > startFill)
{
if (!bufferInit)
{
bufferInit = true;
fireReady = true;
Monitor.PulseAll(syncRoot);
}
else if (decoderStopped)
{
Monitor.PulseAll(syncRoot);
}
}
}
if (fireStarted)
{
OnBufferStarted();
}
if (fireReady)
{
OnBufferReady();
}
}