VS9: Editing DVD Video without losing quality

[FunkyMan]

Hi guys... I want to make some simple edits to a DVD MPEG-2 file and then resave it as MPEG-2 without losing quality. Anybody have a step-by-step as to how to do it?

I tried opening the video in VS9, then editing it. I then used Tools to save it as DVD 4:3 (which it is). It re-rendered with no problems, but I think the saved version was slightly choppy and the audio a bit out-of-sync.

Anybody have any ideas?

[DVDDoug]

First the theory...

The trick is to avoid re-coding (re-rendering).

It depends on what you mean by "simple edits". You can cut and splice an MPEG without degrading the quality at all. But, any "real editing", like crossfades (or other transitions), filters, etc., requires the MPEG to be decoded and re-coded. MPEG is lossy compression, and you loose some quality with each encode.



In practice...

NOTE - Mostly due to sync problems, I'm no longer editing MPEGs with Video Studio. So, I've forgotten some of the details.

If you keep the same bitrate as the original, Video Studio should not re-render, except where required. For example, when I made a crossfade, the video was very "blocky" during the transition. (This may have something to do with "smart render", but the recommendation seems to be to avoid smart render.)

I've been using a special-purpose MPEG edior called Womble ($50 - $100) for MPEG editing for about a year. Since I started using Womble I haven't had any more "lip-sync" problems (or any other occasional weird problems).

Womble's new high-end ($140) program can do some simple DVD authoring, but you will probably want to keep using Video Studio extract the DVD to an MPEG file, and for DVD authoring.

If you only want to cut and splice MPEGs, VideoReDo ($50) is a good choice.

[THoff]

Also, if you use the SmartRender feature, UVS should only need to decode/re-encode the portions of the video that have actually changed by adding a video filter or title to it -- if all you do is cut and splice, UVS can keep the video from the beginning up to the last closed GOP before the editing point, as well as from the first I frame following the editing point.

[FunkyMan]

Well, I'm not sure what's happening, but even when I just crop a video file (i.e. use the trim handles and then inserting it into the timeline), it re-renders the video file.

I'm saving the video file by taking the clip into the video timeline. I then use Tools, Create Video File, NTSC MPEG-2 file.

Is there another way to do this without re-rendering the file. I'm inserting no effecs (no crossfading or anything).

Thanks!

[GuyL]

Are your project settings the same as your video clip? Are you rendering the file to these same properties as well with smart render on?

[TDK1044]

Yeah, make sure that all of your properties are identical to the original file. This is especially important relative to the field order, because if the field order of your rendered file is different from the original file, you may well see choppy pictures.