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1. Re: CS4 exporting magic?
Bill Hunt Nov 2, 2010 10:31 AM (in response to seiurus)Just a guess here, not knowing what settings the client used, but it is likely that that Export to tape created a compressed file, so you have MPEG compression (or similar) twice.
Also, that file size increase is to be expected, as the original MPEG is GOP (Group of Pictures), while the AVI Uncompressed is full I-frame. This ARTICLE will give you a bit of background.
If you can get the exact workflow and settings that the client used, someone here can likely point out exactly why the quality loss.
Good luck,
Hunt
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2. Re: CS4 exporting magic?
JSS1138 Nov 2, 2010 3:55 PM (in response to seiurus)I would hardly expect data lost in taping to be found somewhere and put back!
That is actually precisely what happens. In fact, it HAS to happen or you don't have an image. There isn't a display in the world that can show you a compressed image. They all have to be decompressed back to RGB in order to show you the picture.
The issue at hand is how closely the restored image is to the original. Obviously, the more you throw out in compression, the more the decompression stage will have to "guess" at the missing data. Those "guesses" are where artifacts, anomalies and other image degradations show up. It is entirely possible that whatever method of decompression he used was creating inferior "guesses" compared to what Premiere was doing for the Uncompressed export.
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3. Re: CS4 exporting magic?
seiurus Nov 2, 2010 4:04 PM (in response to JSS1138)Jim,
Thanks for your reply. It still seems too good to be true. Canon has told me that the compressed data on the tape is actually in 4:2:2 (although the official compression to tape is 4:2:0) and that the 4:2:2 information can be accessed by decompression software. If that is true, I wonder why people spend so much money on devices like Nanoflash to collect 4:2:2 via HDSDI port?
Steve Siegel
mobile (305)343-2179
answering service 24/7 (305)865-9861
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4. Re: CS4 exporting magic?
Bill Hunt Nov 2, 2010 4:44 PM (in response to seiurus)Steve,
You might want to disable your signature in your posts (likely from e-mail), as personal data can be easily harvested in a public forum.
Good luck,
Hunt


