laptop workflow/speed questions

I'm confused -
Sounds like PKraft is saying the download speed is a function ( or limited by) the P2 card & the HD specs ,
and Barry is saying its limited by the write ability of the Hard Disk.
 
P2 offload speed is limited by whatever the slowest element in the chain.

P2 card speed = 80 megabytes per second.
PCMCIA bus speed = 133 megabytes per second (no bottleneck)
4-drive SATA RAID = 80 megabytes per second (no bottleneck)

Firewire cable = 50 megabytes per second (potential bottleneck)
USB2 cable = 60 megabytes per second (potential bottleneck)
Laptop internal hard disk = 25 megabytes per second (BIG bottleneck!)

So typically, P2 offloading speed is limited by how fast your hard disk is. If you go to a SATA or SCSI or FiberChannel raid, then that will eliminate that as a bottlenec, and so then you have to look at firewire vs. usb2 vs. PCMCIA.

But the fastest it will ever be is 50 seconds for a 4GB card, because that's the limit of the card speed.
 
Would a 7200 RPM disk speed-up appreciably over a 5400RPM disk?
(Raid is way to much bother for alptop field work for me.)

I assume processor speed is not a bottleneck here then.


Thanks for a clear explanation again.

Hey don't you ever sleep?
 
Never. This writing thing has wacked my schedule out. I find I get most of my best work done between 10 pm and 5 am. Makes no sense, but that's how it goes, so I gotta go with it... :)

Faster drives would help, or so you would think. I bought a TravelStar 7K100, which is supposed to be one of the fastest 7200rpm laptop drives in existence, but it didn't make any difference in my USB2 On The Go enclosure. There's also the Seagate Momentus 7200RPM drives which are supposed to be mega-speedy.
 
hmm...now i'm confused...maybe i haven't been paying attention...

i was under the impression that the latest update for FCP had it so you could work with the P2 mxf files straight of the card?

if it's the case that you have to sit through a conversion process to quicktime before you can use it then that seems to go against their promotion of "whack in the p2 and edit"...

or am i just crazy?..lol
 
Don't worry, I just tried this today and it was plenty fast & easy from the P2 to FCP- and this in an 800 Mhz laptop.
 
robo3687 said:
i was under the impression that the latest update for FCP had it so you could work with the P2 mxf files straight of the card?
Click to expand...
Not yet. It is updated so that FCP knows what the files are and can read them off the card and convert them to QT's, but it's not to the stage yet where you can just edit the MXF's directly.

if it's the case that you have to sit through a conversion process to quicktime before you can use it then that seems to go against their promotion of "whack in the p2 and edit"...
Click to expand...
Avid and Canopus can do that, but FCP can't yet. You do have to do the conversion process. It's speedy & easy, but it would be nicer if you didn't have to execute the conversion.
 
Is the "conversion process" adding another layer of compression to the footage (ie, "re-compressing" to Quicktime format) or is it just a direct pixel-for-pixel conversion that leaves the footage readable to FCP? I'm assuming they wouldn't introduce a solution that recompresses the image, but it seems like if it's pixel-for-pixel, FCP should just be able to read it as is...
 
Lenilenapi said:
I assume that it wouldn't make a difference if you went to internal or external firewire drive then either?
Click to expand...

I've seen reports that say an internal HD connection is generally speedier than usb/firewire connected drives (even if the external drive has better specs). I've also seen reports that say never use your system drive for media recording, so I guess the ideal solution is a laptop with a second drive slot and a really fast notebook drive.

Having said that, the reviews of the G-Raid Firewire 800 drive indicate that with a 1394b connection, these things blow away anything you could squeeze into a laptop. That's the route I'm taking for now. Now, anybody want to mail their HVX to Germany so I can test out my (semi) portable studio? I'd be willing to pay shipping expenses of course (one way :evil: ).
 
Not sure if anybody mentioned it, I was just skimming. This is in reference to one of the more unimportant aspects as most others have been covered. I thought the original poster was asking about "double sided" dvds, not "dual layered". If he did mean double sided then any superdrive should manage fine. They work just like regular, single layer dvds. You just flip them over when you've done one side. Dual layer just seems like an enormous waste of money to me. For the same price you can get one 2.4x dual layer disc you can get six 16x single layer discs. Haven't looked into double sided though... 8GB or 28GB... I know I'd rather have single layer. It burns faster so you get it all done quicker. Just make sure you have a decent sized disc wallet to store them in so they aren't all over the place. Doesn't take up too much space, either. Still less space than film. ;)

As for the camera and HDD... I know the firewire bus is shared but is USB on a seperate bus? If it is, that would be a better choice, wouldn't it? Camera on firewire, HDD on USB. I don't know if it is or isn't. Maybe somebody can help with this one.
 
All this tech talk is too much for me. If I were looking for a powerbook today I'd buy the refurbished 15inch that Apple is selling for 1400 dollars. Freakin' good deal and it can certainly work as a P2 offload station. Check the specs at their site!
 
Barry_Green said:
One minute per gig is the going rate, so I'm sure that's what you meant.
Click to expand...

I've been thinking about this a tad, and it troubles me a tad. One minute per gig is around real-time; and about 17MB/s, or 133Mb/s.

The 100Mb/s of the HVX (~103 w/audio?) rate of live streaming is pretty darn close to this.

I wonder where the bottleneck is? I really don't feel so confident about capturing so close to the maximum throughput of the system, if the bottleneck is on the PC side.

However, I've tested and can transfer large files drive-to-drive over FW (400) at over 30MB/s. So I'm thinking the P2 bottleneck may lie either with Cardbus or... dare I say it... P2?

Can anyone with a camera and/or P2 card and two fast HDDs do a test to see where in the system the bottleneck lies? If you can transfer better than 17MB/s over firewire (or between internal and firewire, etc), but not from P2 to a drive over FW, then something on the P2 end (card or Cardbus) is the culprit.

Or, does anyone have a P2store? that should also be going significantly faster than realtime...

Finally, if anyone has, say, a Cardbus FW card and can confirm that it handles throughput higher than 17MB/s, it would help... I don't have one, but I think I've read reports that indicate speeds are competitive with internal FW800...
 
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