Apple Final Cut Pro Legacy Forum
Any loose of data due to multiple exports? (Quicktime movie)
Any loose of data due to multiple exports? (Quicktime movie)
by Joseph Torres on Aug 19, 2014 at 5:55:02 pm

I've done my research, but I would like somebody to verify this. Let's say if you are done with a particular timeline & you "export" "Quicktime movie", which is suppose to be like a copy of the uncompressed raw footage meaning no quality gets lost. Lets say if I was to open up a new "sequence" & I plant that Quicktime movie onto my new timeline & then I once again "export" "Quicktime movie". Basically I would like to verify if doing this multiple times will harm the video quality in any way, shape, or form. Thanks!


Re: Any loose of data due to multiple exports? (Quicktime movie)
by Shane Ross on Aug 19, 2014 at 6:02:35 pm

As long as it is the same codec, zero quality is lost. It's just writing all the 1s and 0s in a new location. compressing it is where the 1s and 0s change.

Shane
Little Frog Post
Read my blog, Little Frog in High Def


Re: Any loose of data due to multiple exports? (Quicktime movie)
by Andrew Kimery on Aug 20, 2014 at 12:09:59 am

There are some caveats to using Make QuickTime Movie. First off, it only works for cuts only and no FX. If you have a dissolve or a color effect or anything that alters the footage then that section will have new media generated for during the export process. The other caveat is that it only works with intraframe codecs (like ProRes, DVCPro HD, DNxHD, etc.,) and not interframe codecs (HDV, XDCAM, etc.,). If you using Make QT Movie with an interframe codec you'll end up with all new media in the exported file as that's just the nature of the beast with itnerframe.

If you are using a high quality codec (like ProRes 422 or better or one of the higher bit rate DNxHD codecs) you can export, import, export, import, export, import, etc. a number of times before there is any visible quality loss. I think ProRes 422 can go through something like a dozen rounds of decompression before it starts to break down.


Re: Any loose of data due to multiple exports? (Quicktime movie)
by Shane Ross on Aug 20, 2014 at 12:38:34 am

Know it all...

:)

Shane
Little Frog Post
Read my blog, Little Frog in High Def


Re: Any loose of data due to multiple exports? (Quicktime movie)
by Andrew Kimery on Aug 20, 2014 at 12:50:07 am

[Shane Ross] "Know it all..."

I can't help it, it's the AE in me. lol


Re: Any loose of data due to multiple exports? (Quicktime movie)
by Joseph Torres on Aug 20, 2014 at 10:35:43 pm

One more thing!

So Andrew & Shane, let's say if I was using ProRes 422 & either I import & export without ever altering anything (although that would be completely pointless but using it as an example) or I re-add a certain clip (source clip) to any parts of the "Quicktime file" (already had an export) that I want to edit (color correct, video effect etc.), will the quality still begin to degrade eventually if you keep exporting, importing, exporting, importing, exporting etc.?


Re: Any loose of data due to multiple exports? (Quicktime movie)
by Andrew Kimery on Aug 21, 2014 at 1:17:31 am

To keep with your example, as long as you have a ProRes clip (or clips) in a ProRes timeline and the image itself has not been modified (i.e. cuts are fine, dissolves are not) you can import, export, import, export using Make QT Movie as much as you want and the image quality will not deteriorate. If you do modify hte image (add color correct, text over picture, a dissolve, etc.,) then I think the normal ProRes 422 codec will start to visibly degrade after about a dozen import/export cycles. I can't remember the exact number but I think it's around a dozen.


Re: Any loose of data due to multiple exports? (Quicktime movie)
by John Pale on Aug 20, 2014 at 2:08:24 pm

The title of this thread made me think it would be a lot more interesting. I really had to find out what "loose" data was. Total click bait. Does it mean promiscuous data? Loss of data was kind of a letdown :)


Re: Any loose of data due to multiple exports? (Quicktime movie)
by Joseph Torres on Aug 20, 2014 at 10:23:30 pm

lol I meant "loss" my fault. Thanks a ton for the help Andrew & Shane!





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