The single frame flash.

farss wrote on 5/29/2004, 3:56 AM

OK, so I've seen it happen. I'd always thought this only afflicted those with long complex projects or who had been smoking bad weed. But I'm doing cuts only on a silent movie, all of one track.
Here's what I saw happen.
Merrily spooling through the movie looking for bad splices to cut out, found one, hit "S" and trimmed to the left, started trimming to the right and Shuttle wouldn't let me trim past a certain point. Very odd.
So I dragged the rest of the long clip way to the right and hey presto I could trim off the frames I needed to. Butted it back up and just to see tried trimming off a bit more and it got stuck again.
So once again I slid it way of down the time line and had a very careful look to see if anything was in the gap. I noticed one of the ruler grid lines was just slightly fatter than the rest, zoomed all the way in till one frame filled the timeline but the line was only one extra pixel wide still, zoomed back a way and scrubbed over that point with the Shuttle, and yipes, one frame flash from the clip I'd been trimming. I managed to stretch this micro frame out to a full frame and then and only then could I delete it.
Now before anyone asks, yes I've had Quantize to Frames on the whole duration of the project. The only thing turned on that I don't normally have on is Automatic Crossfades.
No big drama for me, I fixed it fairly easily but I can sure see how that one microframe could wreck someones project.
Now I know zip about the internals of the project file but it looked to me like there was a reference to the clip on the TL that had the same in and out points, in other words I'd managed to create a zero length clip. Problem is with Quantize to Frames on when that point is hit this 'no length event' is made the minimum event size namely one frame. I can reproduce this at will, trim a clip to zero frames in length and it's still there. What I cannot seem to do is get it to appear as a single frame flash. Still it's a mighty dangerous thing to have left on the TL. Zoomed out a bit you'd never notice it.

Hope this helps, of course maybe a total red herring as well.

Bob.

Comments

craftech wrote on 5/29/2004, 4:46 PM

Sony Tech offered a free software upgrade if anyone with the problem will send their drive to them. Nice offer and I have had the problem again, but didn't want to send in the drive.
Sometimes I can't find the flash frame at all, but in this most recent case I found it (several of them) from somewhere else in the video as usual. I was unable to trim it properly (Vegas 4) so Ioaded it into the Trimmer and it WASN'T THERE. Yes that's right, it appeared ONLY on the timeline, but not in the trimmer. I checked the exact same spot where it appeared in the timeline and looked before and after it and it was not there.

John

farss wrote on 5/29/2004, 5:34 PM

John,
so if you zoomed right in on the TL could you see anything?
The behaviour I saw seemed logical, a clip had been trimmed to zero length but rather undesirable I would have thought. Zoomed right in all I could see was a slightly fatter ruler. I couldn't see anything at first as the frame was behind another clip and wouldn't (shouldn't?) have appeared in the rendered output but I can see how it could easily end up in the rendered output and I can also see how it could end up elsewhere in the project.
The only way I can see to cure this problem is some extra code that deletes a clip of less that one frame in length but that may cause other issues.

Bob.

craftech wrote on 5/29/2004, 5:47 PM

John,
so if you zoomed right in on the TL could you see anything?
===========
Yes. This was actually the first time I could see the flash frames (there were 5.5 frames this time) after zooming all the way in on the timeline. But logically, they should also show when transferred to the trimmer, but they didn't. I could actually still see them on the timeline and then looked down and saw the proper footage in the trimmer. Most annoying.

John

farss wrote on 5/29/2004, 8:59 PM

So this seems highly reproducable behavior to me, well I can make it happen at will yet Sony keep saying they cannot repo the problem. Maybe they've been looking at this the wrong way, perhaps they're assuming it's a real bug whereas it's actually untoward behaviour that's tripping people up.
This wouldn't be the first kind of problem either where something that Vegas does is quite logical given its core design philosphy yet in the contect you may be working in isn't the behavior you would think to lookout for.

jaegersing wrote on 5/29/2004, 9:35 PM

I've just has a flash problem too, not for the first time, but this is the first time I've seen it with quantize to frames set (first time with Vegas 5 too). I didn't have any very short clips, so it's obvious that different circumstances can trigger it.

I had 2 clips superimposed on tracks 7 and 8, and both were time-stretched for slo-mo effects. The top clip also had a chroma key applied, to let parts of the lower clip show through. When playing the timeline, I saw a flash about halfway through these clips, and the image shown during the flash was 4 frames from a clip used earlier in the timeline. There is no way it should have been showing at this point.

I actually removed the flash without a lot of effort - this is the first time I have managed to do so. I reapplied the top clip as a take, and then reselected the original take. No more flash.

For sure this is a bug.

Richard Hunter

craftech wrote on 5/30/2004, 6:24 AM

Ok, so someone send their hard drive to Sony Engineering. The offer for any Sony software for free plus other "goodies" sounds good and maybe they will get to the bottom of this problem once and for all.
Offer
John

rmack350 wrote on 5/30/2004, 4:47 PM

Are these all NTSC projects?

Rob Mack

jaegersing wrote on 5/30/2004, 5:29 PM

I work mainly in PAL, so it's not just an NTSC problem.

Richard Hunter

jaegersing wrote on 5/30/2004, 5:35 PM

Some more info, in case it helps anyone come up with an idea about this.

In this case, the flash happens when 2 clips are superimposed, as described already. What I didn't mention is that if I mute EITHER (or both) of the tracks involved, the flash doesn't happen. Only when both tracks are used in the playback do I see the problem.

Richard Hunter

craftech wrote on 5/31/2004, 5:46 PM

farss wrote on 5/31/2004, 6:49 PM

IF (BIG IF) this is the problem I've raised they don't need a hard drive or even a .veg to produce it. Just put any clip on the TL, with or without QTF on and trim it till it disappears, i.e. make it zero length.
What happens would seem logical in one context. You haven't deleted the clip so it should be there.
Except unless you look very carefully you don't see it. If that zero length event ends up behind another clip or elsewhere on the T/L all sorts of wierd things could happen without you noticing it. Even the 'I got a single frame from anothe project' problem.
Consider this, you leave the zero length clip on the timeline and as it's almost impossible to see you delete all the media except that and then start using that project as a new porject. But buried inside your new project is a reference to a clip from the last project. Get that reference in the right place and you're going to see it flash on the screen.

Bob.

jaegersing wrote on 5/31/2004, 10:29 PM

Hi John. After I fixed the problem by reapplying the top clip, it would not reappear afterwards, despite several attempts to make it come back.

I have a feeling that this bug is related to render previews, and that Vegas is displaying a previously-rendered segment at the wrong timeline position. Since my temporary storage folder is on a different hard drive, it is possible that sending the project drive to Sony would not allow them to repro the problem anyway.

Richard