DVDR to mpeg, edit and back to DVDR *** Will I lose quality.

[catdog6]

I am putting home movies on DVDR successfully. I am curious though
if I want to pull video back off of DVDR and edit and put back on DVDR will I lose quality. Do I have to reencode??

Thanks,

Kevin

[garryheather]

I hate answers like this... it depends.

OK, the short answer is yes, you probably will lose quality, but how much depends on a number of factors.

If you use an editor that can edit a closed GOP MPEG stream AND the original video was encoded in such a manner, then it should be possible to edit out "chapters" of the original footage and not lose any discernable quality (since you're just chopping out stuff, not re-encoding again with a lossy compressor). There may be some processing required to recreate a compliant stream, but that will be it. The editor will probably have to do some decompression and re-encoding if only to edit the audio portion of the stream which, whether you like it or not, will probably mean a re-encode unless you've got access to some pretty pro-gear.

However, how many of us encode with a closed GOP structure with view to editing ? I would expect that you would import your media into your editing app, which would do something to it like turning it into a compressed AVI or something, and then use that for the editing process. That would then be recoded accordingy. So MPEG2 would have thrown loads of data away the first time, and then when re-encoding it again even more would get lost - so it is most likely that you will have some degredation, but it could be minimal and not too discernable.

Check out your software - words like "lossless compression" "or uncompressed" when applied to the editing engine are good news. Otherwise keep your edit passes down to a minimum. Do all your edits at once without saving and reloading the video in order to keep the number of parent generations down to an absolute minimum, and if you do have to decompress the MPEG2 in order to edit to say an AVI, try not to use any more encoders that could throw away even more of your valuable data.

HTH.