// The Vorbis header is in three packets; the initial small packet in
// the first page that identifies basic parameters, a second packet
// with bitstream comments and a third packet that holds the
// codebook.
public int SynthesisHeaderIn(Comment Comment, Packet Packet)
{
var Buffer = new NVorbis.Ogg.BBuffer();
if (Packet != null)
{
Buffer.ReadInit(Packet.packet_base, Packet.packet, Packet.bytes);
// Which of the three types of header is this?
// Also verify header-ness, vorbis
{
byte[] buffer = new byte[6];
int packtype = Buffer.Read(8);
Buffer.Read(buffer, 6);
if (buffer[0] != 'v' || buffer[1] != 'o' || buffer[2] != 'r' || buffer[3] != 'b'
|| buffer[4] != 'i' || buffer[5] != 's')
{
// not a vorbis header
return (-1);
}
switch (packtype)
{
case 0x01: // least significant *bit* is read first
if (Packet.b_o_s == 0)
{
// Not the initial packet
return (-1);
}
if (Rate != 0)
{
// previously initialized info header
return (-1);
}
return (UnpackInfo(Buffer));
case 0x03: // least significant *bit* is read first
if (Rate == 0)
{
// um... we didn't get the initial header
return (-1);
}
return (Comment.unpack(Buffer));
case 0x05: // least significant *bit* is read first
if (Rate == 0 || Comment.vendor == null)
{
// um... we didn;t get the initial header or comments yet
return (-1);
}
return (UnpackBooks(Buffer));
default:
// Not a valid vorbis header type
//return(-1);
break;
}
}
}
return (-1);
}
private void DecodeInit()
{
convbuffer = new byte[convsize]; // take 8k out of the data segment, not the stack
SyncState = new SyncState(); // sync and verify incoming physical bitstream
StreamState = new StreamState(); // take physical pages, weld into a logical stream of packets
Page = new Page(); // one Ogg bitstream page. Vorbis packets are inside
Packet = new Packet(); // one raw packet of data for decode
Info = new Info(); // struct that stores all the static vorbis bitstream settings
Comment = new Comment(); // struct that stores all the bitstream user comments
DspState = new DspState(); // central working state for the packet->PCM decoder
Block = new Block(DspState); // local working space for packet->PCM decode
bytes = 0;
}
