private void ReadSpecialForm(BitSplitter bs)
{
byte[] data = bs.RemainingBytes();
if (data.Length < PacketLength)
{
throw new DemuxException("Invalid PES: packet shorter than described");
}
MemoryStream ms = new MemoryStream(data, 0, PacketLength);
FrameData = ms.ToArray();
}
/// <summary>Digest data into structured packet</summary>
public Packet(byte[] RawPacket)
{
if (RawPacket[0] != 0x47)
{
throw new DemuxException("Sync byte missing");
}
PCR = -1; TableId = -1; PayloadIs_PES = false;
BitSplitter bs = new BitSplitter(RawPacket);
ReadTransportHeader(bs);
if (PID == 0x1FFF)
{
return; // null packet
}
CheckAdaptionField(bs);
payload = bs.RemainingBytes();
CheckPayloadType(bs);
}
private void DecodeElementaryStream(BitSplitter bs)
{
int marker = (int)bs.GetInteger(2);
if (marker != 2)
{
throw new DemuxException("Invalid PES: first marker missing");
}
ReadFlags(bs);
if (bs.BitOffset != 0)
{
throw new DemuxException("Alignment problem in PES (internal)");
}
HeaderLength = (int)bs.GetInteger(8);
int head_start = bs.ByteOffset;
if (HasPTS && HasDTS)
{
ReadDTS_PTS(bs);
}
else if (HasPTS)
{
ReadPTS(bs);
}
if (HasESCR)
{
bs.SkipBytes(6); // not currently used.
}
if (HasEsRate)
{
bs.SkipBits(24); // not currently used.
}
if (UsesTrickMode)
{
bs.SkipBytes(1); // ignored
}
if (MoreCopyright)
{
bs.SkipBytes(1); // ignored
}
if (HasPesCRC)
{
bs.SkipBytes(2); // ignored
}
if (HasPesExtension)
{
ReadExtendedHeader(bs);
}
// skip anything that's left
int head_end = bs.ByteOffset;
int to_skip = HeaderLength - (head_end - head_start);
if (to_skip < 0)
{
throw new DemuxException("Invalid PES: declared header length did not match measured length");
}
bs.SkipBytes(to_skip);
// Now, the remaining bytes are data and padding
int data_length = PacketLength - (HeaderLength + to_skip);
if (data_length > 3)
{
data_length -= 3; // no idea where the '3' is coming from...
}
byte[] data = bs.RemainingBytes();
if (PacketLength == 0) // video is allowed to not specify
{
data_length = data.Length;
}
#if DEBUG
if (data.Length < data_length)
{
throw new DemuxException("Invalid PES: packet shorter than described");
}
if (data_length < 0)
{
throw new DemuxException("Invalid PES: Negative packet length");
}
#else
if (data.Length < data_length || data_length < 0)
{
data_length = 0;
}
#endif
MemoryStream ms = new MemoryStream(data, 0, data_length);
FrameData = ms.ToArray();
}