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-   -   XDCAM on a Mac.. Compression? (https://www.dvinfo.net/forum/sony-eng-efp-shoulder-mounts/106301-xdcam-mac-compression.html)

Mike Moncrief October 23rd, 2007 05:57 PM

XDCAM on a Mac.. Compression?
 
Hello,

When you import XDCAM file via Firewire, (Using FCP or even the standalone software) does the Video go through another compression step?? I believe it is stored on the XDCAM as an MPEG2 file.. Just wondering what exactly happens to the video as it is imported in using the firewire cable and it becomes a quicktime?? Versus if the video comes in 10 bit uncompressed via SDI??(I realize the file size will be way bigger.. but wondering about compression and quality of the images..)

Thanks,
Mike M.

Greg Boston October 23rd, 2007 06:01 PM

Bringing in the clips via XDCAM Transfer is a process of separating the audio, video, and metadata out of the MXF wrapper, and then re-wrapping into a QT compatible container. No re-compression of the mpeg2 is taking place.


-gb-

Mike Moncrief October 23rd, 2007 06:06 PM

Hello,

So if you capture the same clip uncompressed via SDI and again using the firewire import, there will be absoulutley no difference at all in the 2 clips???(besides filesize of course)

Thanks,
Mike m.

Greg Boston October 23rd, 2007 06:09 PM

Quote:

Originally Posted by Mike Moncrief (Post 763560)
So if you capture the same clip uncompressed via SDI and again using the firewire import, there will be absoulutley no difference at all in the 2 clips???(besides filesize of course)

Not sure since I don't have uncompressed capture capability. But you could check this by exporting with both methods, exporting an uncompressed still of the same frame and doing a difference key.

-gb-

Mike Moncrief October 23rd, 2007 06:23 PM

OK, Well Theoretically, if what you are saying is true, then they should be identical?? Yes??

Mike M.

Nate Weaver October 23rd, 2007 06:30 PM

I'll ignore that you seem to be talking SDI vs. HD-SDI.

But yes, if you captured XDCAM HD via HD-SDI to 8-bit uncompressed, it would NOT look better than if you brought it in via XDCAM Transfer.

This works exactly like DV. When you bring in via firewire/FAM, you're just pulling the native data off the disc, which is as good as it will ever be.

Capturing to uncompressed, generally speaking, is just a big waste of space. I can think of a few circumstances in which this might be the way to go, but they're pretty few.


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