Using HDTV sets with your Mac through FireWire

So far, getting an HDTV set to interface with your desktop computer has been quite a hassle on both Mac and Wintel platforms. Fortunately, some recent software component additions by Apple are paving the way.

Apple has been quietly working on MPEG over FireWire capabilities for some time. As part of the Firewire Software Development Kit (SDK) 17, there is support and example tools to talk to MPEG devices over FireWire. For anyone with a 1394 enabled TV, HDTV Tuner, Sony MicroMV camcorder or the new JVC HDTV Camcorder, this is a major boon that will almost certainly make its way into the standard FireWire driver software in Mac OSX.

MacFixIt reader John Wolf writes "One example program included with the FireWire SDK is 'VirtualDVHS.' As the name implies, it turns your Mac into a DVHS VCR, capable of recording MPEG2 digital video in both HD and SD resolutions. In my case, I can plug a G4 laptop into that Mitsubishi TV with a single FireWire cable and record HDTV shows to the computer, similar to a TiVo or ReplayTV box. With the Mits TV, and reportedly the Samsung ATSC Tuner, the computer is controlled by the TV/Set Top Box. I can schedule a show to record, and as long as the computer is connected and VirtualDVHS is running, the show is recorded on the computer for later viewing.

"The Mitsubishi 65869 will even record in the background while I watch one of the other inputs on the TV. The computer can play these shows back to the TV, or if you have a DVHS deck connected, it can record the show to the DVHS deck. If it isn't obvious, this only works for Digital TV broadcasts that come in over the DTV antenna input, it doesn't magically convert any of the other inputs on the TV to MPEG2 for recording over FireWire.

Wolf notes that there are still some bugs with this setup: "On a few occasions, I have gotten a kernel panic when launching Virtual DVHS when the computer wasn't connected to the TV. I tried to use a clamshell iBook with FireWire, and that didn't work at all. If you want to edit the video after it has made it onto your computer, you will find the tools are very immature, especially for error prone HDTV broadcasts with AC3 aduio. VideoLan Client can play the files directly, but you will need the fastest Mac available to play HDTV (1920*1080) files without dropping frames. The tools to convert from the native MPEG2 Transport Streams (TS) to the more common Program Streams (PS) aren't for the faint of heart. However, once you get them converted, and change the AC3 audio to another format, QuickTime can deal with them. The optional MPEG2 QuickTime decoder is required."

You can download the FireWireSDK17 from the Apple Developer site and try out VirtualDVHS and DVHSCap yourself. VirtualDVHS requires installing pre-release FireWire drivers.

Resources