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XDCAM-EX superior to ProRes for realtime FX?

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Ken Pugh
XDCAM-EX superior to ProRes for realtime FX?
on Jul 11, 2011 at 10:16:31 pm

In between evaluating PPro, I've been editing some rushes in XDCAM-EX format in FCP7 - and been getting a lot of crashes (FCP suddenly disappears, in a flash, often after dragging the cursor in the timeline). So I decided to media manage the cut sequence and convert to ProRes 422, to see if I could minimise the crashes. However the ProRes timeline has much poorer real time performance - which surprised me.

For example, the XDCAM footage in a XDCAM sequence will play with no green render bar after applying the broadcast filter. However the same clips transcoded to ProRes 422 in a ProRes timeline go green with the broadcast filter applied!

Now I would have expected the opposite - given XDCAM is a predictive Mpeg codec - and ProRes a single frame codec. Anyone know why the performance of the ProRes footage should appear to be poorer than the Mpeg?

Cheers,

Ken.

8 core Mac Pro 8 Megs RAM
Kona Lhe
SATA 4 drive RAID with Sonnet E4P (360 M/sec)
10.6.7 FCP 7.0.3


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Tony Silanskas
Re: XDCAM-EX superior to ProRes for realtime FX?
on Jul 13, 2011 at 4:28:45 am

I gave up trying to work with XDCAM EX natively in FCP because of the constant crashes like you describe. The bugs were never worked out by Apple. Transcoding to ProRes fixed the crashes problem and I haven't looked back.

As far as slower performance with ProRes than XDCAM EX, it could be a few things but we need more info about your project to see if there is a problem or your just experiencing normal performace with ProRes:

- Can you explain a bit more when you say "much poorer" real-time performance? You didn't say the playback was worse with your example, just that the bar turned green and green bars play back fine most of the time for me.

- What version of ProRes did you transcode to? ProRes Proxy, ProRes 422, ProRes 422 HQ, etc.? What frame size? 1080p, 720p, etc.? XDCAM EX has an average bitrate of 35mbps while standard ProRes 422 is about 147mbps so ProRes needs faster drives to playback in realtime. And since ProRes is a larger-size (less compressed) codec it will take longer to render for some things because the files are larger. A small price to pay for a superior codec (in FCP eyes at least).

[Ken Pugh] "Now I would have expected the opposite - given XDCAM is a predictive Mpeg codec - and ProRes a single frame codec."

- This is a bit of a common misconception since XDCAM EX is a pretty efficient codec and isn't bogged down by the Mpeg factor nearly as much as some people say. Just try it in Adobe Premiere and it's much smoother to work with than FCP since most of the FCP bugs aren't there. And with the much smaller bitrate than ProRes you get faster performance all around. This is why many news stations use XDCAM EX.

tony

http://www.HungryCliff.com


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