Problem between timeline and preview window

zyzzyx wrote on 3/12/2004, 12:38 AM

I seem to be having a strange timing discrepancy between clips on my timeline and when they begin to display in the preview window. The problem only shows up at very high zoom levels, but is there none the less. I’ve been working with Vegas for almost a year, and I don’t remember noticing this until after I installed the latest update (4.0e). I would like to know if this is something others have experienced, or if my installation has somehow gotten corrupted.

For this example I have my timeline set to show “absolute frames,” and I am zoomed in on the timeline so that each press of an arrow key advances the cursor by .001 of a frame. I am starting with a new file using the NTSC DV template.

If I drag a solid color (let’s say, blue) from the Media Generator to the timeline, the properties for that clip indicate that it is 299.700 frames in length. If I then drag another color (say, yellow) and snap it to the end of the previous clip, the timeline shows it beginning at frame 299.701. So far, so good.

The problem shows up when I move the cursor from the end of the first clip into the beginning of the second clip – or from 299.700 to 299.701. I would expect at that point for the preview screen to follow the cursor and change from blue to yellow as the cursor moves from the blue clip to the yellow clip. However, on my system the preview screen stays blue until the cursor gets all the way to 300.000, at which point it finally changes to yellow – even though the cursor has been moving through the yellow clip on the timeline ever since 299.701.

It is very unnerving, to say the least, when the timeline shows I am in one clip, but the preview screen is still in the previous clip. Has anyone else seen this phenomenon?

Thanks, Z

Comments

TheHappyFriar wrote on 3/12/2004, 6:04 AM

If something goes to frame 299.001 to 300.000, it will look the same (since frame 299 started on, say, blue, it's blue until frame 300).

Video can only be edited by the frame (and hence only display what you would see if you played it). If you wanted to edit in more detail, just increase your FPS. I set a project to 60fps, so there are 60 frames in a second, so i can edit at 60 pointed in a frame instead of 30 (and you would see this 299.7 frame thing wshow up because it's not frame 299.7, it's frame 599.4, and the 2nd clip starts at 599).

zyzzyx wrote on 3/12/2004, 8:33 AM

Thanks THF. So if I understand you, the difference in what I'm seeing (cursor in next clip while preview still shows earlier one) is really a function of the project's frame rate.

That begs another question: if I were to set my frame rate at an even 30fps for editing, and then reset to 29.97 for rendering, wouldn't that give me more precise control of my edits over all? Is there any reason I wouldn't want to just do that as a general practice?

Z

TheHappyFriar wrote on 3/12/2004, 9:14 AM

29.97 is (normaly) the same as 30fps. In 29.97 an ocational frame is "dropped" (not realy dropped though, so don't worry, it's a numbering thing) so that a color picture will look good on a color TV (at 30fps way back when a color picture would flicker slightly, but 29.97 didn't). This all started years ago, and is no longer an issue with modern technology, but we still do it because that's the NTSC std. That's one of the things that is susposed to be "updated" with digital TV too.

I think i'm right. :)

HPV wrote on 3/12/2004, 9:33 AM

FIrst you need to turn on Quantize to Frames on the top tool bar. Now you can only place events on frame breaks. Second, the media generators don't give you an accurate default event length of 9:29. It's more like 9 sec. and 29 and 3/4 of a frame. I've posted about this but Sony hasn't responded. New still frame duration prefs setting can also give problems. You want to set it to just start a new frame. So one second would be 1.001, five seconds would be 5.005. Use the arrow keys in the prefs interface to fine tune or hold down the ctrl key while you drag up and down over the numbers.

Craig H.

HPV wrote on 3/12/2004, 9:36 AM

Forgot to tell you that you can drag and snap the end of the partial frame media gen. event to fix it.

Craig H.

johnmeyer wrote on 3/12/2004, 10:21 AM

Zooming way in is useful only for editing audio which is sampled 48,000 times per second. The video is sampled only about 30 times per second (or 60, if you count each field as a separate sample).

zyzzyx wrote on 3/12/2004, 11:00 AM

Thanks for the input, guys. Its nice to know there's nothing wrong with my setup. A shift in perspective is a much easier fix.

Z