View Full Version : Offload to mass storage: express/34 geek knowledge sought.


Scott Auerbach
February 16th, 2006, 08:05 PM
I'm new to the forum, and about to be new to the HVX200 (unless something scares me off)...have been researching it like crazy for a week or so. I'll try to make discrete threads that hang on a single topic or related topics... so here goes the first one:

I remember reading here or on another forum that the soon-available Express/34 card connected to a SATA external drive will allow data transfer rates up to 3 Gbps. If that's the case (and it appears to be, from what I can deduce), then what does this mean for P2 transfer to external storage? Can the P2 spit out data that fast, or not? Not having a clue about the internal construction of these things, I don't know if there'd be a bottleneck inherent in the chip design.

Anyone want to chip (pardon the pun) in on this? Anyone?... Bueller?

Barry Green
February 16th, 2006, 09:44 PM
The P2 card has a maximum transfer rate of 640mbps.

If you wanted to use it in an ExpressCard slot though, you'd need some sort of adapter. The P2 card conforms to the CardBus 32 PCMCIA form factor, not ExpressCard.

Robert Lane
February 16th, 2006, 10:04 PM
Currently, the only method for getting P2 clips into a MacBook Pro would be to connect the camera directly to the FW port and make a transfer in "host" mode to either the internal or external drive.

See my response to your other thread for more info.

Jeff Kilgroe
February 16th, 2006, 10:37 PM
I know I'm picking nits, but there's also the P2 Drive unit from Panasonic which has slots for 5 P2 cards and connects via USB2. Unfortunately this unit has an MSRP of $2499USD. Their new DVCPROHD deck also has slots for P2 cards, so there are other (although much more expensive) options than simply commecting the camera.

32bit CardBus PCMCIA is actually capable of up to 1052Mbps and we may see P2 cards grow beyond the current 640Mbps capability, which is the current speed limit induced by the 133X SD chips being used in the cards.

As for ExpressCard slots, as Barry said, you will need some form of adapter. Hopefully an ExpressCard to PCMCIA adapter does come available in the future. ExpressCard also comes in various sizes (34, 54 and 72). The numbers actually represent the width of the slot in millimeters, but the EC72 has dual connectors for duplex or dual-channel performance. Apple most likely chose the 34mm form factor due to space constraints. But this will require any PCMCIA adapter solution for the new 15" MacBook to be a completely external one.

Scott Auerbach
February 17th, 2006, 01:27 PM
640...ouch.
I guess that's still 1/6 realtime, but slower than hoped-for. But if the external drive sits on an Express/34 card, then the only way to get the chips connected to the camera (without Panasonic's deck) is any forthcoming PCMCIA-to-Firewire adapter, so you're down to 400 Mbps...

Let me back up to an earlier response...
In "host mode", the camera acts as a playback device across Firewire, a la playback from a conventional camcorder? Does this work for all resolutions and frame rates? I saw the FireWire limitation to 1080i/60, but perhaps that's only for streaming live video from the camera? I assumed it was a global limitation. Given the lack of any head wear, there's no reason to not use the camera as a host device (other than the problem of having to stop shooting in order to offload, which is nothin' to sneeze at.)


The P2 card has a maximum transfer rate of 640mbps.

If you wanted to use it in an ExpressCard slot though, you'd need some sort of adapter. The P2 card conforms to the CardBus 32 PCMCIA form factor, not ExpressCard.