Strobing Problem

soundguy63 wrote on 10/21/2002, 9:22 AM
Some good news and bad news to report. First the bad. On my last two projects in VF, several segments in the middle of the program have acguired a "strobe-like" effect and I havent been able to figure out why it happened. I captured and edited everything just like normal. When I printed to tape I realized the defect. It's so subtle that its very difficult to notice on the preview window, so I had failed to realize that it's actually occuring to the clip on the timeline. The original clips dont contain the problem and carefully replacing the clips on the timeline with the same clips fixed the problem. I was very careful not to accidently stretch or compress the speed of the clips during the original edit. One project was captured from mini-dv on a dv deck, the other was captured from a Digital 8 camera. Each project was captured to a different harddrive, each of which was separate from the OS drive. Anyone else seen this problem? I'm running Windows 2000 on a PIII, now with 3 harddrives.
Which leads me to part of my good news. I recently bought a firewire enclosure and installed a spare 20gig harddrive in it. Connecting to the computer went perfectly and it was by far the easiest HD installation i've ever done. I highly recommend firewire drives as the way to expand your system (with one exception, see below). In case you're wondering, the strobing problem first occured on my original media drive before this installation. It occured the second time after this installation when I captured to the firewire drive. The only problem I've had with the drive was that the system refused to print the rendered file back out to tape. It seemed that, despite having no problems capturing from firewire and writing to the disk via firewire on the same firewire card, the system couldnt read the file back through firewire and out via firewire to the deck. There was no response, like the system was confused on how to work with the two streams on one card when going back out to tape. I simply copied the rendered file to my internal media HD and then printed to tape normally. Anyone running into this one or have a solution? I'm using a Pinnacle dv card with two external firewire ports.
Lastly, I just installed Vegas on Friday and so far havent seen any problems, but I wanted to try and fix these issues in VF because I'll be moving it to another machine. Thanks in advance, Jay

Comments

ralphied wrote on 10/21/2002, 12:07 PM
I have run into the EXACT same problem. I, too, thought I was being very careful not to do any "unusual" editting to introduce this strobe effect. While I haven't completely figured out what's causing it, the problem appears to be the result of trimming clips by "dragging" the ends of the clips. I have changed my method of trimming clips to using the "[" and "]" keys to bound the clip region to be deleted, highlighting the region (by double-clicking on the region bar above the time-line) and pressing the delete key. Using this method (which has been for approximately 1 month now and five, 1.5 hour editted videos later), I have not experience anymore "strobe" effect problems.

There appears to be a subtle bug in VF's trimming algorithm when using the "drag" method.

Hope this helps.
soundguy63 wrote on 10/22/2002, 9:46 AM
Thanks, that was my feeling exactly. I will try your method and see if that eliminates the problem.
I think in addition to dragging the ends to set clip length, the bug may be related specifically to dragging the ends into a crossfade with another clip. This was the only place it showed up, after a crossfade with another clip or full-screen graphic.
Although it only occured about 10% to 20% of the time, not after every crossfade. It never occured after a cut, even if dragging the ends had been done there.
Was that a similar experience to yours?
Thanks again for the info!
ralphied wrote on 10/25/2002, 8:49 AM
I can't say that I looked that closely as to just exactly where the problem was occurring. Your observation on the cross-fades, though, may be correct. All I know is that ever since I've changed to the [] method, I've never run into the problem again.

It would be nice if somebody from Sonic could comment on this issue.