AVI format - lossless?

[wgkenney]

Hi all,

I've got several .avi's that I have rendered from Vegas 5. As I recall, .avi is a lossless format. If I take the .avi's back into Vegas, add transitions, titles, etc and then rerender as an .avi will there be any loss on quaility since I am going from .avi to .avi.

I then encode to MPEG in a different program.

Thanks

Glenn

[Cornucopia]

AVI, like QT, is an A/V container format. What determines whether it's lossless or not is the codec that is used. Some are, some aren't.

My guess is the default codec you're using would be of the DV variety. This is lossy, but it holds up fairly well to repeated (within reason) re-encodings. Some are better than others-Canopus is known to be one of the best, Microsoft's seems to be one of the worst.

Nevertheless, you should ALWAYS try to minimize the # of times you re-encode.

HTH,

Scott

[Richard_G]

DV avi isn't lossless but the compression is done in the camcorder or DV encoder. The transfer to your computer is lossless in as much as it is a file copy and not a capture. I don't know about Vegas, but most software will only re-encode anything that has changed and leave untouched footage as it is. I use Ulead Mediastudio Pro and they call it Smartrender, but I would suspect Vegas does something similar. For example, if you have two clips and do a crossfade from one to the other, the two clips won't be re-encoded, only the frames that include the crossfade as they didn't exist in the original clips. If you do a straight cut from one clip to the other, nothing has changed so nothing gets re-encoded.

If you aren't talking about DV but some other format of .avi, then it might be different.