intermittant frames

Rick K wrote on 9/7/2003, 1:09 PM
SCREEM....
You know when you've been working on a project for hours on hours and something totally fucks up thats going to take you an hour to resolve when you THOUGHT you were done, you get pissed off Right?
I'm going to calm down now, I can resolve this BUT...
I have placed MPEG 1 movies into frames, sizing them so that text from JPEGs (originally from a power point presentation) appear above and below. I noticed on the final cut that the text at the top was out of the frame on my TV. So I go back and move everything around. In doing so, I resize my MPEG1 movie that's appearing in a space on the left hand side. of the viewing area. When I play it back, it starts skipping frames. I have been fighting with this problem on other parts of the project where I have just deleted the problem without knowing why. Now a perfectly good picture showing construction activity (which really adds to the final product) is completely hosed. Yeah, I'm going to try and re-insert it. And the answer may simply be to not mix MPEG1 with AVI, Hell, I don't know. Just a LITTLE frustrated. Wondered if anyone knew about this.

Comments

Chienworks wrote on 9/7/2003, 1:23 PM
Working with MPEG can be very problematic. You might want to try converting them to AVI files first, then using the AVI files in your project.
Jessariah67 wrote on 9/7/2003, 4:04 PM
avideo,

Are the "skipped frames" you're talking about during preview, or in the final render? Once you start compositing or adding lots of effects, etc., you will get an undersampled-like drag in your preview, depending on the juice you've got and how much you're putting into it. If this isn't the problem, then I misunderstood, but a dynamic RAM preview might save you a whole lotta time if I'm right.

HTH
Rick K wrote on 9/8/2003, 11:00 AM
No, I don't think it's undersample drag. I know what that is.

Lets have a closer look at this: I'm printing to DV tape then transferring to VHS. So I noticed it on the VHS, but turns out it's also seen during the preview though it didn't BEFORE printing to tape. (curious, huh?) I think this problem has to do with re-sampling; something I don't understand. (maybe flags I've set without knowing their effect?)
The big clue is this:
I have printed the same project to DV tape 3 or 4 times. The first time, all MPEG-1 avideo was forced to be resampled. It took 3-4 hours for an eighteen minute tape. Gees. I also got a warning that 85% of the tape had been pre-rendered, did I still want to proceed? Sure!. Like I said, it took better than 3 hours. This project is mostly scrolling text and and few stills and some video to try and make this dry subject interesting. So I notice missing frames or frames with a blank interlace alternating on and off on the VHS tape. I tried to correct this in the project but simply couldn't. The segement could be altered to make the intermittant frames go away. SO I deleted the segment in question, printed to tape a second time. The customer complained some text was pressing the limits of the screen so I made some changes, and again printed to tape. A NEW segments became intermittant. (explitive deleted) All I did to it was resize it using the 'crop' utiltiy so I could fit the text on the screen. So last night I got home free by deleting yet another video segment and adding some canned still pictures in its place. The final 'print to DV tape' took about 30 minutes. Hmmmm....why not longer? I only removed 30 seconds of video total. So, what's happening?

Customer will be here in a few minutes to view the final product. I think I'm home free but wonder what's happening. I don't think this is a bug at the moment. But I need to understand it.
Rick K wrote on 9/8/2003, 12:33 PM
Chienworks,

A...how would you do that exactly? I have this as a CD. How do I convert it into a *.avi?
Chienworks wrote on 9/8/2003, 12:34 PM
One very simple and straightforward way is to load the clip onto Vegas' timeline by itself and render to a DV .avi file. After that, use the .avi file in your project instead of the original .mpg file.