|Originally posted by chap
A D-VHS box uses a different protocol then what your pc knows. I think if you can figure out the protocol then you have a shot, but that means you have to litterally decipher the language that those things talk between each other.
I'm sorry--you're both right and wrong. That's not generally true, but it is true in the case of the 169time mod, as I recall. There's some proprietary lingo going on between the old Panasonic deck and TU-DST5x's that Sixteen Nine Time uses, making their modification incompatible with any of the new D-VHS decks. However, as I pointed out before, there are some drivers for Windows that talk the underlying AV/C, EIA-775-A and EIC 61883 protocols. DTCP on 1394 is built on top of this stack of protocols--you shouldn't have any problem talking to the JVC or Mitsubishi deck using software built on top of these Windows drivers (just so long as the tape wasn't copy-protected--you can't implement DTCP without obtaining a valid set of keys, which the DTLA must be keeping under heavily armed guard).
The online documentation for Window's support for AV/C starts here
. Note the text on this page:
|Microsoft supports the Audio Video Control (AV/C) protocol, which is built upon the IEC-61883 standard.
The AV/C protocol driver Microsoft supplies is called avc.sys. It is a functional driver that supports the AV/C subunit protocol. The AV/C subunit protocol is a method for issuing commands and sending responses from subunits on devicew such as MiniDV camcorders and digital-VHS tape deck. For example, a MiniDV camcorder has two subunits, a camera subunit (the imaging device) and a tape subunit (storage of the media-signal). A digital-VHS tape deck has a tape subunit and a tuner subunit. These subunits can be controlled externally from a computer if the camcorder is connected to a PC through the IEEE 1394 serial bus and appropriate "subunit drivers" are written for the hardware. These drivers are WDM drivers that connect to the AV/C system-supplied driver (avc.sys) to provide that control.
So the necessary support is in place on Windows, with all the AV/C and IEC 61883 protocol stuff already written for you--you have to write a minidriver for D-VHS tape subunits (unless, of course, you'd also like to control any tuner that might be there, requiring an additional minidriver). A description of their AV/C command set is freely available online here
. (You would also need to implement many of the common requests described in this
spec). The Windows support that's in place relieves you of having to know any
of the line protocol details--your driver just has to manage the procedural details of operating the tape deck. You'd also have to write an AV/C streaming protocol driver to capture the video after you'd set up the connection to your card and sent the PLAY request.
The drivers would implement functions to enable those operations--after writing them you'd need to write an application which would use them to manipulate the VCR, acquire and buffer data and write it to a file.
None of this is at all easy, but it's one hell of a lot simpler than starting from scratch, as you suggest is necessary.
But the original poster's question was whether you could record HDTV to a PC using a regular FireWire card from a 169time mod and again, you're right--that won't work, because the Panasonic D-VHS deck was not properly compliant to these protocols and 169time uses their added stuff. The Windows FireWire A/V protocol stack won't deal with that.
-- Mike Scott