Re editing dvd's

mel58i wrote on 12/8/2005, 3:28 AM
I'm trying to re-edit some of my wedding work on dvd to make a compilation album to give to potential clients.
I do not have the original AVI files.
Should I rip the VOB files off the dvd's and try to edit in Vegas (with transitions/effects etc) to make the compilation, or should I render them into AVI first and make Vegas's job a little easier?
I am concerned that the quality of the re-edit may be affected on the compiled dvd.
Wonder if anyone has had experience in this?

Mel.

Comments

JohnnyRoy wrote on 12/8/2005, 6:59 AM
I would think that the highest quality would be achieved by editing the VOB files directly. This way they will only go through one more recompression to MPEG2 again. Creating AVI files will indeed be easier on Vegas and more accurate because you will be editing a full frame copy, but it is one more recompression and an opportunity for loss in quality (although DV compressing at 5:1 is much lighter than MPEG2 compression at 25:1 and may result in no perceptible loss)

The only way to be sure is to test both ways on a small sample and see if you can tell the difference once it is rendered back to DVD. Make sure the sample has high contrast i.e., hard edges from dark color to light. This is the toughest test for the MPEG encoder and will show the most artifacts (as will high motion)

~jr
johnmeyer wrote on 12/8/2005, 8:14 AM
I do this all the time. I have ranted many, many times about Sony's inability to understand how many people are going to want to do exactly what you are trying to do, and for the very reasons you state. For lots of information, do a search on VOB and my user name.

Here's the short version of all those posts:

Workflow1: Copy VOBs to your hard drive. Put VOBs on Vegas timeline and edit. Advantage: Straightforward. Disadvantage: No audio. Video is recompressed, even if doing simple cuts-only edits. Editing is jerky and slow (because Vegas doesn't cache GOPs).

Workflow2: Same as #1, but use DVD2AVI to convert the AC-3 audio (which Vegas will not read) into WAV that Vegas can edit and read. Advantages and Disadvantages: Same as #1, except you get audio.

Workflow3: Same as #1, but after putting VOBs on timeline, immediately render out to a DV AVI file. Start a new project and use this AVI file, along with the WAV file created in Workflow #2. Advantages compared to #1/2: Quick, responsive timeline editing. Disadvantages: Extra step taking more time and more disk space before you can start editing. Possible loss of color space if original DVD material contained media that was in the 4:4:4 or 4:2:2 colorspace (e.g., generated media, still photos, etc.).

Workflow4: Skip Vegas. Use one of Womble's products (MPEG-VCR or MPEG Video Wizard). You should also be able to use VideoRedo, a product I have not yet used, but which sounds intriguing and is less expensive than Womble's over-priced offerings. Advantages: Completely lossless MPEG-2 editing (except at non-GOP cut points where a few frames are re-encoded). AC-3 audio is also cut, without loss. Very quick for cuts only. Can cut directly from the disk, saving time of copying to hard disk (and saving disk space). Disadvantages: Have to learn another editor. Limited editing options compared to Vegas.

Obviously Workflow4 is the way to go, if you've got $100 to spend for Womble's product. It is what I do most of the time. It is what Sony should add to Vegas. They don't need to get fancy, but since HD is MPEG, they sure as heck are going to have to do all the work anyway, at some point, so why not start by doing this relatively simple thing? (I say simple, because they have -- or have access to -- all the MPEG-2 technology.

Hope that helps.

Laurence wrote on 12/8/2005, 8:18 AM
I use MPEG Edit from womble.com for this sort of thing. It smart-renders mpeg, just rewriting the edited parts. The bulk of the mpeg is just copied into the new file with no rerendering. Be aware that it does mess with the mpeg frame structure a bit, so I wouldn't use it for complicated edits, but for simple re-edits it works great. Because it doesn't rerender the whole file, it's really fast too.