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How to get file to be recognized as 30fps vs 29.97 initially
Posted: Fri Mar 27, 2009 8:34 pm
by vidpro2u
Hello,
I have a camera that shoots 30fps mpeg4 ASF 16X9 on an sd card.
When I get the media file off the card via vsprox2 the file appears as a thumbnail and also shows up fine in the preview but when I click on the properties of the file itself it shows 29.97 @ 720X400. And it plays the audio and video out of sync barely. I looked at trying to change the movie project settings to 30 fps but I must choose frames based and still plays audio and video out of sync. How can I get these types of files to be recognized as 30 fps instead of 29.97?
Posted: Fri Mar 27, 2009 10:16 pm
by Ken Berry
Welcome to the forums!
What are you wanting to do ultimately with the video? If you intend to burn it to DVD, then you have no choice but to use 29.97 fps since that is the international standard requirement for NTSC DVDs.
For the sake of completeness, I would note that the international standard frame sizes required for NTSC DVDs are 720x480, 704x480, 352x480, or 352x240. So your video would need to be padded out horizontally from 400 to 480 if burning to a DVD...
Posted: Wed Apr 01, 2009 1:09 am
by DVDDoug
in the preview but when I click on the properties of the file itself it shows 29.97 @ 720X400. And it plays the audio and video out of sync barely.
The "lip sync" problem shows-up in preview? Does the original file play OK in Windows Media Player? Have you tried finishing-up the project and playing the final file (or DVD in you're making one)?
And, maybe it really is 29.97, and they just say "30"...
If the lip-sync error is constant (it's usually not), you can fix it by exporting the audio to a separate audio editor. (Maybe you can fix it with Video Studio's audio editor... I'm not sure.) It can be tedious to find the right time-adjustment, but it's simply a matter of adding a bit of silence to the beginning of the audio file, or by trimming-off a bit of sound at the beginning. Or, if the sound is ahead of the video and you don't want to loose any sound, you can add blank (black) frames to the video.
I'm not sure if the framerate is at the root of the problem. It shouldn't be an issue if the audio and video play together at slightly the wrong speed. For example, PAL DVDs (25 fps) typically play 4% faster than the film (24 fps). (29.97 fps NTSC DVDs are converted from film with "3:2 pulldown".) And, if everything's "working right", you can save a file at a different framerate without messing-up the sync.
MPEG-4 can frequently be difficult to edit and/or convert, and you can get any number of "strange problems", including A/V sync problems.