Tweaking a capture...

[merlin001]

A couple questions, actually. First, if I capture from my DSS to my computer via s-video (Dazzle Hollywood DV Bridge) to 720x480, would IVTC accomplish anything good? My other question is about IVTC. My understanding is that when you IVTC an NTSC source, you basically drop 6 frames every second. If a 45 minute capture has 75k frames and you IVTC it, you wind up dropping 15k frames. Stupid question, I know, but won't that actually shorten the capture and break the AV sync?

Thanks!
~ David

[jggimi]

NTSC video that you capture will be 29.97 frames per second. If you IVTC it, you do indeed remove approximately six frames every second. But at the same time, the framerate drops to 23.976fps, so the length of the video doesn't change. This is done for Telecined content, which is NTSC video typically made from 35mm film, designed to be projected at 24 fps.

A nice IVTC tutorial is at www.doom9.org/ivtc-tut.htm -- it's focused on post-processing avi files, and talks to DVD2AVI project files, and frameserving via AviSynth filters. But even if the tools you use are different, you'll be needing similar filtration capabilities in order to produce similar results.

[tluxon]

It's my understanding that dropped frames do not shorten the video or cause audio and video to be out of synch. I'm pretty sure most encoders will simply replace a dropped frame with a duplicate copy of an adjacent frame.

Tim