Comments

jrazz wrote on 4/6/2006, 6:28 AM
For capturing video- DO NOT USE USB. Firewire is fast, USB is slow= lots of dropped frames. If you have USB 2.0 that should work fine, but I don't know of a camera (maybe some out there) that is using USB 2.0 as a standard for video output.
FIrewire is less demanding on your processor while USB is processor intensive.

j razz
JohnnyRoy wrote on 4/6/2006, 7:00 AM
Just to add to what jrazz has said: Since both are just data pipes, there is no quality issue with regard to “picture quality” as long as all of the frames are transferred. Obviously dropped frames will affect the quality. USB 1.x is not fast enough for DV transfer so speed is the issue there. It’s not a matter of taking longer, it simply doesn’t work.

As for firewire and USB 2.0, the difference is that firewire doesn’t require any CPU overhead. It will transfer the files and leave your CPU free to do other things. USB is CPU intensive. Your CPU is actively participating in the transfer and if another program wakes up and demands CPU resources, you may get dropped frames as the CPU stops transferring to process other things. While both firewire 400 and USB 2.0 are rated at about the same transfer rate, you will probably never achieve that theoretical rate with USB.

Another difference is that USB divides the bandwidth across the ports. So if you have two USB devices they each share half of the bandwidth whether they are using it or not! If you place a hub on a port, you are further dividing the already divided bandwidth!!! (USB hubs are not a good idea for high throughput / time critical devices) Firewire has the same bandwidth on every port.

You can capture successfully with USB 2.0 if your camera supports this, but firewire is more reliable (because it isn’t affected by CPU load) and therefore is the recommended transfer mechanism.

~jr
jeff-beardall wrote on 4/7/2006, 7:40 AM
i capture to USB 2.0 all the time...never drop a frame. I also capture to Firewire 400 & 800...no appreciable difference when capturing. Playing back a timeline is also pretty similiar...similar frame rates from all 3. The FW800 certainly is faster for simple file transfers. There is no difference in quality at all.
farss wrote on 4/7/2006, 7:56 AM
What's being referred to is using a USB interface from the camera I think.
I suspect also though that the USB 2.0 interface on later mobos may be way better than the earlier stuff, it certainly seems dramatically faster on my latest PC compared to the older ones with USB 1.
johnmeyer wrote on 4/7/2006, 10:48 AM
i capture to USB 2.0 all the time...never drop a frame. I also capture to Firewire 400 & 800...no appreciable difference when capturing.

... and then ...

What's being referred to is using a USB interface from the camera I think.

Just to reinforce that point: The connection to your external drive can be either USB 2.0 or Firewire (1394) and you can capture without dropping frames (although, as JohnnyRoy points out, the CPU burden is higher with USB). The quality will be exactly identical in either case.

However, the connection to your camera MUST be Firewire. The USB connections that some cameras provide is for a lower quality version of the video, or is for the transfer of still pictures from the memory card. Do NOT use this connection.