FCP7: Eliminating ProRes 422 File Size Reduction?

[David Roth weiss]

In theory, you simply export using Export>>QuickTime Movie, at current settings. How were you doing it before?

David Roth Weiss
Director/Editor/Colorist
David Weiss Productions, Inc.
Los Angeles
http://www.drwfilms.com

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Colorist – UP IN THE AIR (electronic press kit) – nominated for six academy awards

A forum host of Creative COW’s Business & Marketing and Apple Final Cut Pro forums. Formerly host of the Apple Final Cut Basics, Indie Film & Documentary, and Film History & Appreciations forums.

[Melanie Price]

Thanks for the reply! We’ve been exporting exactly that way and the Pro Res file we get out of FCP is still roughly 30% smaller than the one we started with. We’ve also tried exporting multiple files via Batch Export with the same results, a ~30% drop in file size.

[John Pale]

Are you exporting to a smaller external drive, but capturing to a large drive array? If so, the file sizes can be quite different.

[Melanie Price]

We are capturing from our deck through a Blackmagic Decklink to one system’s scratch disk (~1 TB of free space, 3.6 TB total size) and then another computer accesses the file through the network, and on that second machine it is edited and exported to Machine #2s internal hard drive (~500 GB).

[Melanie Price]

PS- The files are small. The captured file is ~2.5 GB and the file we get after the export through FCP is ~1.8 GB. Roughly a four minute clip.

[Bret Williams]

Are you per chance capturing 8 tracks of audio and exporting only 2 or zero or something of that nature?

[David Roth weiss]

Good call Bret. There has to be some explanation such as that one.

[Rafael Amador]

[Melanie Price] “Is there a setting in Final Cut that would allow me to export a Pro Res file that’s the same size as the Pro Res file we’re starting with? Currently, we’re seeing a roughly 30% drop in end file size from our original. which seems strange since we’re starting with a ProRes 422 HQ and exporting a Pro Res 422 HQ. Is this normal?”
A reduction of the file after re-processing Is not strange at all. Is the VBR nature of this codec.
Re-processing works like a “double-pass” compression, optimizing the info/file size.
However a 30% difference I think that may be pointing to something else.
Was FC working in High Precision?
You may be crunching the Prores to 8b somewhere.
Another element that may be a factor, is the BlackMagic.
Those cards are not Prores native.
I guess that if you capture with an AJA you would get a different file size.
rafael

http://www.nagavideo.com

[Olivier Aubut]

I know that snow leopard displays the file-size differently than Leopard. Are you working with both OS?

[Melanie Price]

When we import the file into Final Cut, it has 4 tracks of audio, and is exported that way. When we re-import the file that has just been exported, it is down to 2 audio tracks. We’ve adjusted the outputs to 4 in the audio settings, and this prompt comes up. We’ve both selected and deselected the downmixing, and either way end up with 2 audio tracks and a drop in file size.