View Full Version : Saving as AVI question


Dan Lahav
December 11th, 2003, 02:48 AM
Is there any loss of quality if i keep rendering my projects as AVI? For example, I want to edit a clip, then render it as an AVI file... Then I want to insert it into a much larger set of clips and save those as one big AVI. Is there any degredation of quality if i keep rendering the same AVI file over and over?

BTW I'm using vegas 4.0e

Kieran Clayton
December 11th, 2003, 02:54 AM
Depends what codec you're using..

DV is a lossy codec, hence each compression and recompression degrades the image.

uncompressed/full frame avi is a non-destructive codec, but the file size is immense.

A halfway house is something like Digital Anarchy's microcosm codec for quicktime, which compresses while simultaneously being non-destructive. It's not a real-time codec though. ie it's great for storage and for sending footage to a client, but for editing and things like that it won't do.

Kieran

Dan Lahav
December 11th, 2003, 02:55 AM
hrmmm im just using Vegas's AVI uncompressed NTSC codec I guess... I dont mind the big file sizes, i have 2x250GB HDD'S :)

Kieran Clayton
December 11th, 2003, 03:50 AM
You might want to consider saving as a quicktime .mov instead.. I believe I'm right in saying that the animation codec gives you a smaller file size than uncompressed avi and is also non-destructive.

If you're wanting to archive things then microcosm is only $99, which is pretty good value.

Kieran

Aaron Koolen
December 11th, 2003, 04:14 AM
Kieran, what compression ratios does Microcosm get? I currently archive my footage and things on MPG2 as a size/quality compromise but if this is close to in size (even 2 or 3 times the size) I would live with that for lossless.

Aaron

Kieran Clayton
December 11th, 2003, 04:26 AM
You'd be better off checking out DA's site;
http://digitalanarchy.com/micro/micro_loss.html

and if you have any questions then the DA forum over at the cow is the place to go to get answers from the company themselves:

http://www.creativecow.net/index.php?forumid=66

Kieran

David Hurdon
December 11th, 2003, 06:33 AM
Dan there have been many tests made available on the effect of multiple compression cycles on various DV codecs, like MS AVI, Canopus, Main Concept. None shows objectionable degredation in a few compressions. They certainly do vary if you run 10 - 50 compressions but who does?

David Hurdon

Glenn Chan
December 11th, 2003, 12:38 PM
The difference between 1st and 2nd generation DV is hard to tell. Adam Wilt writes that it's indistinguishable.

10 (or was it 50?) generations with Microsoft DV is noticeable.
10 generations with Quicktime DV is noticeable. see codecs.onerivermedia.com
vegas's DV codec is supposed to be the same across any number of generations. digitalvideoediting.com has a picture of it in their Vegas review.

DV compression is pretty reasonable. I wouldn't go out of my way to avoid it unless you are using really crappy codecs, which you aren't.

Dan Lahav
December 11th, 2003, 04:43 PM
thanks guys, got all my questions answered :)