Editing demuxed video, dropped frames problem...

[beansandjeans]

Hey - I posted this question over at the doom9 forum too, but I figured I should post it here as well, cuz someone on this site might have some insights...

Ok, so here’s the situation – I’m working on video production, and I have some footage on DVD that I want to edit and mix with other footage (don’t have the original DV tape). We do have a DV capture deck with A/V inputs that we can plug a DVD player into for re-digitizing, but I’d really like to avoid the generational loss of going from digital to analog and then back to digital. (I’ve also yet to find any DVD player with firewire outputs).

So what I’ve been trying to do is demux the DVD (I’ve been using DoItFast4U for demuxing and then an AC3 converter to convert the audio to WAV or mp3) and then import the audio and video files for editing. We’re working on Mac G5s, and I’ve so far been using iMovie and Final Cut Pro. Avid X Pro is also installed, but I haven’t used that yet.

The problem comes when the imported video (M2V file) is rendered. In iMovie the rendering is done automatically when the video is imported and in Final Cut the rendering is done manually. But in both cases, the result is the same – dropped frames! When I import and render an hour and a half of video, the footage ends up being about five seconds shorter than it originally was (which translates into around 150 frames lost – about 100 per hour). I was able to solve the obvious problem of audio synching by using Audacity to make precise adjustments to the audio’s speed. But when I burned the final product to DVD and watched it on my tv, the dropped fames made the video very noticeably jittery and just watching it gave me a headache. So obviously this won’t work for any production.

So does anyone know of any good solutions for this?...

Is there a way to render without losing frames?

Also, I don’t really know why rendering or any sort of transcoding should be necessary in the first place, since we’re starting out with MPEG-2 video from DVD, and we ultimately want to end up with MPEG-2 to burn on DVD. I’m thinking that maybe the software I’ve been using insists on rendering just so they can keep it in their own proprietary format so that we have to keep using their software… Are there any good non-linear video editing programs that can import, edit, and then export M2V/MPEG-2 video without having to do any sort of rendering or transcoding??...

If anyone can give me any good suggestions I’d really appreciate!

Thanks

[Nelson37]

RE-encoding should not be necessary.

Try the process with no cuts at all.

I would suspect that the cuts are happening at the nearest I-frame boundary, loosing up to 15 frames, or one-half second, per cut.

Or that the software is inserting I-frames, and the different GOP length is causing an issue with the software.

I don't touch or have a need to use Macs, so don't know much about software available.

On the PC, however, many progs could handle this.

[beansandjeans]

RE-encoding should not be necessary.

Try the process with no cuts at all.

I would suspect that the cuts are happening at the nearest I-frame boundary, loosing up to 15 frames, or one-half second, per cut.

I already did it without cutting - I just imported and rendered a block of footage (about an hour and a half long), added the audio back in, and then burned it to DVD. I had to adjust the speed of the audio just to get it in synch with the video becuase the video was shortened, and this was before I had made any cuts. I burned the uncut reassembled and rendered video as a test before proceading further with the production.

Or that the software is inserting I-frames, and the different GOP length is causing an issue with the software.

I don't touch or have a need to use Macs, so don't know much about software available.

I also have more experience with Windows/PC, but I've been working on Mac so far because they're availible at our studio with NLE sofware already installed, and because they're a lot faster than my cheap Celeron machine that I've got at home. Though I can switch to whatever platform will work best for me.

On the PC, however, many progs could handle this.

If you or someone else here could reccomend a good Non-linear video editing software that can import and export MPEG-2 without any need for transcoding one way or the other, and that can do basic stuff like adding titles and cross-disolve transitions....If someone could refer me to a software like that (whether it runs on Mac and/or Windows), I would greatly appreciate. (Sorry for the run-on sentence there!) I'd prefer a software that's free/open source, but I can spend money if I need to in order to get the right tool for this job.

Thanks for the help