Rendering MPEG2

Nelpot wrote on 9/28/2004, 9:53 AM

I created an MPEG2 file using Vegas Movie Studio. I want to modify this file with additional transpitions and edits. Is there a quick way to render just the modifications without having to render the whole MPEG2 file?

Thanks

Comments

Steve Grisetti wrote on 9/28/2004, 1:12 PM

As I understand it, MPEGs are a form of compression which uses one master frame every five frames and then bases the subsequent four frames on the master.

In other words, it really is not the best format for editing because, unlike AVIs, not every frame is a true frame.

It's not impossible to edit, but it could well cause more problems than it's worth. You'd be much better off editing your native file and re-rendering the MPEG from it.

IanG wrote on 9/28/2004, 1:44 PM

From an editing point of view it's actualy worse than that! MPEG works with a Group Of Pictures (GOP) made up of Intra (I) frames, which are complete pictures, Predicted (P) frames which are changes from the previous I frame and Bidirectional (B) frames which are based on the previous I & P frames and the next I frame. Depending on exactly how you define the GOP structure you'll typicaly have 1 to 2 I frames per second. It's not surprising that editing MPEG generaly produces poor results!

Ian G.

Nelpot wrote on 9/28/2004, 7:59 PM

thanks for the input.