capturing with huffyuv to external usb 2.0 HD ?

[Heavensent]

anybody tried that ?
seems to drop frames like crazy, could it be that huffyuv is more than what usb 2.0 can handle?

resolution = 720 X 576
cpu = amd athlon xp 2000+
DDR ram = 640 MB 266mhz
capture card = avermedia dvd ezmaker gold

external HD details :

Manufacturer Seagate
Hard Disk Name Barracuda 7200.7 Plus 200822
Form Factor 3.5"
Formatted Capacity 200 GB
Disks 2
Recording Surfaces 4
Physical Dimensions 146.56 x 101.85 x 26.1 mm
Max. Weight 635 g
Average Rotational Latency 4.16 ms
Rotational Speed 7200 RPM
Max. Internal Data Rate 683 Mbit/s
Average Seek 8.5 ms
Interface Ultra-ATA/100
Buffer-to-Host Data Rate 100 MB/s
Buffer Size 8 MB
Spin-Up Time 10 sec


thanks ...

[Heavensent]

anyone??
or am i the only one with external HD for capturing?

[Richard_G]

The one thing you haven't told us is the actual sustained data rate that your hard drive is capable of. This isn't the maximum rate or the buffer to host rate, but how fast you can shift data continuously. You are using PAL full frame and, as huffy is lossless, the file sizes will be pretty large. Try using something like SiSoft Sandra to run some tests and see what the actual continuous data rate is on your external drive. This will give you a figure in Mb per second. I would suspect that it is going to be something like 25 or 30 Mb per second. Then look at the final file size of a capture and work out how many Mb per second of footage this works out to. Ideally, your drive needs to be capable of at least 30% greater than you are trying to write to it at.

USB 2.0 is fast, so that probably isn't where the bottleneck is, it could be the ATA 100 drive interface. ATA 100 (supposedly) gives a maximum burst rate of 100 Mb per second, in reality it is usually less than this. The sustained rate is much lower still. Alternatively, it may just be something simple like the drive needing to be defragged. The sustained data rate on a fragmented drive is much lower than on a defragged one.

[Heavensent]

if i connect the HD directly inside the computer, the capture turns out fine and without droped frames.
so its not the ata 100 interface, and its not fragmented eather
i will try to make a benchmark on the data rate it can handle,
anything ealse you can think of?

thanks by the way...

[Richard_G]

If the drive works OK inside the computer, it's definitely something to do with the USB transfer. I assume that both the motherboard and drive case are USB 2.0? Are there any settings for either of them, maybe the connection has defaulted to USB 1.0 for some reason.

[Heavensent]

the motherboard originaly supports usb 1.0 only,
but i installed a usb 2.0 pci card and it appears in the device manager as usb2.0 root hub.
sp1 is also installed.
how whould i check if the connection between the external HD and the
computer is actualy working at usb 2.0 or usb 1.0 ?

[Richard_G]

I don't know how you can check if the USB is working as 1.0 or 2.0 but Sandra will tell you what the data transfer rate is to the external drive. It may also be able to tell what USB standard is being used (it seems to be able to tell most things). Although you have a USB 2.0 root hub in the pc, are you sure the external drive carrier is USB 2.0 as well?

[BJ_M]

why usb is not used in studio's -- only firewire ..

usb is not good for sustained transfers like this, yes it CAN be done , but it is more resource intensive and a few other things .. leave usb to printers and cheaper scanners and mice and use firewire for real work ..