IIRC, ATSC is Advanced Television Systems Committee, responsible for the high definition TV standard for the US. See . This is mostly an MPEG2 transport stream, at about 19.3 mbps (8.5 GB / hour!) which is what those of us with digital TV cards (Hipix, HiDTV, etc.) capture from US digital stations. But if your code has the Next_Transport_Packet() function in it then you did indeed pick up the version with support for this. Nifty! I didn't write that code and don't know about dual audio streams. (or much audio at all) But except for extracting the MPEG2 elementary stream from the transport stream HDTV data looks pretty much like DVD VOB's, with AC3 audio in them, and big resolutions like 1920x1088i. I'll just test some and see what happens. ;) - Tom