AVI to MPEG2 (before and after) question

[David Allen]

I am still shooting in SD. I bring in my AVI video, edit it and convert it to MPEG2 for burning to a DVD. I was hoping that someone with more tech knowledge than myself could answer this question. If I convert my AVI to MPEG2 first and then edit it, will the quality of my final product be the same?

With the bigger projects that I run (sometimes two hours with multiple cameras) my computer would not have to struggle so hard.

Any help would be appreciated.

Thank you.

David

[Don Bloom]

I also still shoot SD and it's my opinion that you are better off staying with the workflow you have. MPEG is a harder codec to edit. Edit the orginal codec (avi) as it's really what came from the camera, then convert. Yeah it might be a longer render to mpeg but if you compress it first then edit how do you know how long the finished product will be to set the bitrate. You might end up overcompressing it.
YMMV

[Jay West]

What NLE are you using that edits multi-cam mpeg2 more easily than avi?

On every computer and NLE that I've owned -- and I've been shooting and editing multi-cam events for going on 17 years --- it has been the other way around. Mpeg2 is much more highly compressed than avi so, on every system that I know of, editing mpeg2 imposes decompression and computational loads which simply do not exist for avi. AFAIK, the only way mpeg2 is lighter on an editing computer is that mpeg2 occupies less disk space.

Is your problem that the avi files for a two-hour multi-cam project fill up so much of your hard drive that your computer is struggling because it is running out of disk space? Are you trying to do multi-cam editing on a laptop while using the same hard drive for both your operating system and video files? If so, you would be much better advised to get a 7200 rpm external hard drive with firewire or eSATA connections and use that for your video files. Frankly, converting from avi to the much more highly compressed mpeg2 for editing strikes me as pulling a horse trailer with a SmartCar. It can be done, but why would you want to?

If a second hard drive is not feasible for you, then, depending on the NLE you are using, you might be able to lighten the load on the computer by either lowering your playback resolution during editing or by using proxy files.

[David Allen]

Don & Jay,

Thanks for your reply. Obviously I don't know what I am talking about. I made an assumptions that the smaller mpeg2 file would be less taxing on the computer. I am using Sony Vegas Pro 9 and my video is always held on a 7200 rpm, 500gb second hard drive. I have been using several other editing programs for years but I am fairly new to Vegas Pro. When I brought all my video into the timeline, I saw how sluggish it was acting so I got the bright idea about converting it first and then editing.

My computer will do it, like I said, it just acts very sluggish. I guess I can just edit in 30 minute segments and then put it together after rendering.

Thanks again

David

[Don Bloom]

No problem. It could easily be assumed that the "smaller" compressed MPEG file would be easier to edit but.....

One thing I didn't mention was the PREVIEW monitor of Vegas. Since Vegas is non hardware dependent relying on processor speed and to a certain degree RAM, I almost keep my preview monitor set to PREVIEW>AUTO for the majority of my editing. When at a higher setting depending on what you've got going on as far as FX (color correction, exposure correction, cropping etc) it can really slow down the preview so it plays choppy in the monitor. I've even had a few occassions when I had to drop to DRAFT>AUTO in particular when using Magic Bullet. Also the size of the preview can affect playback, so you might want to size it down a bit and set to PREVIEW>AUTO and see if that takes care of the problem for you.

[David Allen]

Don,

Well my video preview is as large as I can get it and my preview quality is set for the highest I can get, so you are probably right. Thanks.

David

[Robert M Wright]

Perhaps a computer upgrade is in order? Editing SD in Vegas shouldn't be sluggish on any reasonably modern multi-core CPU.

[Harm Millaard]

Originally Posted by David Allen

I am still shooting in SD. I bring in my AVI video, edit it and convert it to MPEG2 for burning to a DVD. I was hoping that someone with more tech knowledge than myself could answer this question. If I convert my AVI to MPEG2 first and then edit it, will the quality of my final product be the same?

David

Plain answer: NO. It will be worse.

Why: Conversion from one format to another will always entail quality loss (unless you convert to a loss-less codec) and MPEG2 with its long GOP structure will require another conversion after editing.

Rule: Always edit the source in the codec it was shot in and stay away from converting to another format until you are done with editing.

[David Allen]

Thanks for all the advice guys. I really do appreciate it.

David