View Full Version : Firewire Issues

Bob A
09-08-2004, 07:13 PM
:confused: I had recent problems with audio out of sync with video when capturing video via the firewire in my vt3 (see audio out of sync with video thread) from my XL1 camera. I seemed to have fixed the problem by digitizing the video via s-video and chosing DV type 1 as the format in the capture window. The audio is perfect with less distortion and the video seems as good or better. My question is why is this difference between firewire capture and analog with s-video? I thought the firewire would be better. Are there certain settings I should have when capturing through firewire?

09-09-2004, 10:06 AM
Search for posts from user Scorpioprod; Eugene has lots of info on this subject.

Basically, if you capture DV type 2 through firewire, some users (myself included) are having audio sync problems. Some aren't.

The solution is: capture type 1 through firewire (you can change between type 1 and 2 in Preferences), or, capture through S-video as you've been doing (if you capture S-video, feel free to capture into DV type 2; it won't have the sync problems firewire capture has, and although VT can use type 1 or 2 equally well, type 2 is more compatible with other software).

Having said all that, I also capture from an XL1 (not an XL1s), and I'm still having slight sync problems even outside VT. (The above sync problem will be dramatic, with the audio becoming a second off after a few minutes. The slight problem is audio becoming a second off after an hour). A user recently said this was a known issue with the XL1 (not XL1s); I'm currently evaluating the best way of dealing with it in VT (capturing analog and avoiding firewire altogether may be the best bet).

How's that, Eugene? -MG :D

09-09-2004, 10:33 AM
I believe by using s-video you can choose Type 1 or 2, since bypassing the firewire latency issue makes the problem moot.
It is only when Type 2 Firewire capture gives you problems, that you shift to Type 1. S-video can use either type.

Consider yourself lucky s-video looks as good as firewire. Means you have a good deck, heads, cables, connections. Firewire can be better than s-video, but not always to the naked eye.


09-09-2004, 01:27 PM
The 29.96 sync problem exists with XL1 and SOME XL1S'.

I used to have the cutoff serial number for the
transition to the fixed technique.

But... since I have one of the later XL1S' with
no sync problem, I've let it slip.

If you get an XL1S, make sure it's a later one...(obviously)

The other solution is...
Use an NLE with a fully adjustable frame rate.