internal bool TryInit()
{
// try to process the stream header...
if (!ProcessStreamHeader(_packetProvider.PeekNextPacket()))
{
return(false);
}
// seek past the stream header packet
_packetProvider.GetNextPacket().Done();
// load the comments header...
var packet = _packetProvider.GetNextPacket();
if (!LoadComments(packet))
{
throw new InvalidDataException("Comment header was not readable!");
}
packet.Done();
// load the book header...
packet = _packetProvider.GetNextPacket();
if (!LoadBooks(packet))
{
throw new InvalidDataException("Book header was not readable!");
}
packet.Done();
// get the decoding logic bootstrapped
InitDecoder();
return(true);
}
/// <summary>
/// Seeks the stream for a valid packet at the specified granule position.
/// </summary>
/// <param name="granulePosition">The granule position.</param>
private void SeekToGranulePosition(long granulePosition)
{
if (!CanSeek)
{
throw new InvalidOperationException("Stream is not seekable.");
}
if (granulePosition < 0 || granulePosition > GranuleCount)
{
throw new ArgumentOutOfRangeException(nameof(granulePosition));
}
// Find a packet based on offset and return 1 in the callback if the packet is valid
var foundPacket = _packetProvider.FindPacket(granulePosition, GetPacketLength);
// Check of the found packet is valid
if (foundPacket == null || foundPacket.IsEndOfStream)
{
_endOfStream = true;
_nextDataPacket = null;
return;
}
// Just seek to this found packet and get the previous packet (preRoll = 1)
_packetProvider.SeekToPacket(foundPacket, 1);
// Update the PageGranulePosition to the position from this next packet which will be retrieved by the next QueueNextPacket call
PageGranulePosition = _packetProvider.PeekNextPacket().PageGranulePosition;
// Reset the state from the decoder to start processing a fresh stream
_decoder.ResetState();
}
private void SkipOpusTags(IPacketProvider packetProvider)
{
DataPacket packet = packetProvider.PeekNextPacket();
byte[] buffer = GetPacketData(packet);
if (Encoding.UTF8.GetString(buffer, 0, 8) == "OpusTags")
{
packetProvider.GetNextPacket();
}
}
internal void SeekTo(long granulePos)
{
if (!_packetProvider.CanSeek)
{
throw new NotSupportedException();
}
if (granulePos < 0)
{
throw new ArgumentOutOfRangeException("granulePos");
}
var targetPacketIndex = 3;
if (granulePos > 0)
{
var idx = _packetProvider.FindPacket(granulePos, GetPacketLength);
if (idx == -1)
{
throw new ArgumentOutOfRangeException("granulePos");
}
targetPacketIndex = idx - 1; // move to the previous packet to prime the decoder
}
// seek the stream
_packetProvider.SeekToPacket(targetPacketIndex);
// now figure out where we are and how many samples we need to discard...
// note that we use the granule position of the "current" packet, since it will be discarded no matter what
// get the packet that we'll decode next
var dataPacket = _packetProvider.PeekNextPacket();
// now read samples until we are exactly at the granule position requested
CurrentPosition = dataPacket.GranulePosition;
var cnt = (int)((granulePos - CurrentPosition) * _channels);
if (cnt > 0)
{
var seekBuffer = new float[cnt];
while (cnt > 0)
{
var temp = ReadSamples(seekBuffer, 0, cnt);
if (temp == 0)
{
break; // we're at the end...
}
cnt -= temp;
}
}
}
internal bool TryInit()
{
if (!ProcessStreamHeader(_packetProvider.PeekNextPacket()))
{
return(false);
}
_packetProvider.GetNextPacket().Done();
DataPacket nextPacket = _packetProvider.GetNextPacket();
if (!LoadComments(nextPacket))
{
throw new InvalidDataException("Comment header was not readable!");
}
nextPacket.Done();
nextPacket = _packetProvider.GetNextPacket();
if (!LoadBooks(nextPacket))
{
throw new InvalidDataException("Book header was not readable!");
}
nextPacket.Done();
InitDecoder();
return(true);
}
internal StreamDecoder(IPacketProvider packetProvider, IFactory factory)
{
_packetProvider = packetProvider ?? throw new ArgumentNullException(nameof(packetProvider));
_factory = factory ?? throw new ArgumentNullException(nameof(factory));
_stats = new StreamStats();
_currentPosition = 0L;
ClipSamples = true;
var packet = _packetProvider.PeekNextPacket();
if (!ProcessHeaderPackets(packet))
{
_packetProvider = null !;
packet?.Reset();
throw GetInvalidStreamException(packet);
}
}
