|Originally posted by Alan Gouger
Firewire is firewire. I use a PC with a firewire input card. I use this for archiving my HD material from the hipix card to my camcorder and back to my hard drive. I would think there must be a way to record right to my hard drive using some sort of software program.
In the digital engineering world, for the past couple of decades at least, when we create new schemes for connecting devices together, we do it in layers. That way, when we're designing a new interconnection, we don't have to start from scratch--we can find something already in use that's close to the characteristics of what we want and use all the layers up to where it diverges from our purposes, and start building new stuff from there. "FireWire" or IEEE1394, is a bottom or "physical" layer--its specs detail the physical characteristics of the various conductors, grounds, insulators and connectors for the different flavors of FireWire, and the electrical scheme for moving basic blocks of data (or "frames") across the wire.
Other soft protocols have been layered on top of FireWire, for different purposes, like plug-and-play device identification to Windows (or any OS that with drivers for that protocol), a protocol all FireWire devices designed to be plugged into PCs can perform: after that protocol has completed and the OS knows what the device is, another set of drivers will come into play which know how to exchange the set of messages specific to the purpose of the device. This would likely be a different set of drivers for a FireWire storage device than for a DV camcorder.
There is an interconnection standard for home A/V networks using 200 Mbps FireWire called IEC 61883, that you can, if you're really, really interested, download a copy of the main portion of at this
page for a number of Swiss Francs equal to about $80. The abstract of the main section of this, IEC 61883-1, reads:
|Specifies a digital interface for consumer electronic audio/video equipment using the IEEE 1394 standard. Describes the general packet format, data flow management and connection management for audiovisual data, and also the general transmission rules for control commands. Defines the transmission protocol for audiovisual data and control commands which provides for the connectability of digital audio and video equipment, using the IEEE 1394 standard.
Layered on to this standard, I believe, was the EIA 775 stuff (see in the list here
, which adds some capabilties for specifying displays and overlays on compliant DTVs, among other odds and ends. The DTCP protocol can be layered on, when desired, to attempt to guard copy-protected content.
Any of the new equipment being introduced (by Sony, Mitsubishi and JVC now) with 1394/DTCP connections should be able to speak IEC 61883 and any of the protocols encompassed by EIA-775-A, and, indeed, transfer and display MPEG without any use of DTCP. Such devices could well interact with your PC FireWire card, if your PC had drivers installed for the protocols that they speak. This
information at Microsoft's Developer's Network Library would indicate that such drivers exist. Using them, a PC connected to a 1394 A/V network could discover the devices on it, and what they were capable of and create and display a menu for controlling them. It could get any digital video source, like a VCR or PVR, to deliver an MPEG stream to it and display that on the PC's monitor (or do anything else it wanted with it, like copy it over the Internet, hence DTCP). It could get any source's digital audio stream and play it through the PC's speakers. All through a single loop of wire connecting the equipment, one wire into each, one wire out--IMHO (see the picture in my post here
), a very cool scheme.
-- Mike Scott