Editing MPEG-2 with VV3

AFSDMS wrote on 10/28/2002, 2:49 PM
This message was also posted as a reply in another thread. . .

I've been using the Dazzle DVC-II hardware encoder to capture MPEG-2 files of older home videos. This device doesn't support uncompressed AVI files. It does a tremendous job as far as quality goes. There are some shortcomings as far as being able to monitor audio levels, etc. But for $200 it is a pretty darn good system. The resulting videos can be burned directly to DVD and are excellent in quality. Also, the video and audio are in sync for the entire clip, from 15 minutes to 90 minutes.

Because I wanted to clean up the captures with nice fade ins, fade outs, and some audio normalization, I brought the MPEG-2 files into VV3 and re-rendered them out again. The original MPEG captures were 8 mBit variable. I would then render them to 8 mBit variable. I know that multiple renderings to MPEG causes some deterioriation, but in my tests it just isn't detectable with my source material (VHS and some 8mm videos) and at the 8 mBit rate.

The strange thing, and one gentleman in Denmark has explained this in some detail, is that while the rendered video starts out in perfect audio/video sync, by 10 minutes in there is a noticable difference that gets worse as time goes on. The gentleman in Denmark gave a fairly detailed technical explanation, stating that VV3 really couldn't be used to edit MPEG videos. What gets me is that the 'Professional' MPEG support should be properly decoding the MPEG I have and making it into some sort of interim format that can be edited and is in sync.

So, does anyone know for certain if VV3 can be used to edit and render videos in the MPEG-2 format. Would I possibly have better luck if my capture was to MPEG-2 wiht a fixed bitrate, then I rendered to a variable bitrate in Vegas 3.

Any help appreciated.

Wayne

Comments

SonyEPM wrote on 10/28/2002, 3:18 PM
Vegas can open (most) a/v MPEGs, but MPEG is not an ideal source format and should be used only when there is no other alternative. MPEG of any flavor will always be recompressed after you do your edits and output to a new file, so expect some quality loss at the very least.

Since it appears you are going to be doing alot of this type of work I would either

a) invest in a device that captures as DV (like the Canopus DVMC DA2) or

b) find a conversion utility (perhaps on www.vcdhelp.com?) that will convert your captured MPEGs to .avi. Use these intermediate files to do your editing, then save to MPEG or whatever at the end of the day.
AFSDMS wrote on 10/28/2002, 3:34 PM
Thanks for the answer. Too bad it isn't what I'd like to hear :-)

I do have a new Sony DV CamCorder that has analog pass-through to the FireWire DV output. Looks like I might end up using that for some of the higher quality transfers I need to do.

Cheers!

Wayne
SonyEPM wrote on 10/28/2002, 3:46 PM
Cool, no additonal $ outlay required. With your Sony DV camera, you have the perfect tool for the job right now.
tadpole wrote on 10/28/2002, 4:16 PM
SonicEPM - you mentioned using a conversion utility to convert mpegs to avi format.

Why can't you just use vegas?
ie - load the mpeg in vegas - then 'render as' .avi?