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SLOW DISK warning on HD multiclip playback

I have a sequence with 3 HD cameras (1920x1080 60i) synced in a multiclip. I'm continually getting the "Warning - Dropped Frames" messages indicating that it was caused by slow disks.

I've noticed that when I have 3 HD cameras in a multiclip I will get this occassionally but in this project I am getting it continuously, every 5 to 10 seconds. The only thing I can think of is that my scratch disc is too full - it has approx 300 gigs available and it is a 3TB drive. That should be plenty of free space as to not effect playback in FCP7, but I am not sure (that's why I'm posting this question 🙂 )

I am working on a MacPro 2.8 GHz Quad-Core Intel Xeon with 10GB 800 MHz DDR2 FB-DIMM. Again, seems like that should be plenty fine to handle 3 HD cams - especialy since the drive FCP is reading from is an internal 3TB, ie, not USB or Firewire. I am running Snow Leapord V10.6.8

Any advice would of course be greatly appreciated.

Thank you,

Eric P

MacPro / PowerBook G4, Mac OS X (10.6.6), FCP 7.0.3

Posted on Aug 28, 2011 4:12 PM

21 replies

poconorm

Level 1

95 points

Aug 28, 2011 10:11 PM in response to Eric Pensenstadler

ProRes422 HQ is only needed if your using a camera that's 2k or higher resolution. Red Camera for example. In your case using that codec is like using a semi-truck to transport a shoebox. Regular Prores will give you the quality that comes out of that camera. ProRes 422 HQwill give you the same quality but with much larger file sizes with no difference in quality. If your needlessly using ProRes422 HQ then you'll definately need a good raid set up but you don't eed that.

Aug 28, 2011 10:17 PM in response to poconorm

ya, I'm still awake.

I love your analogy of the semi-truck for a shoe box!

So, I believe you, and I've read that before, but if you don't mind, just for my understanding let me ask what the difference is then. If the quality will be same, then what's the purpose of the HQ/larger file sizes?

poconorm

Level 1

95 points

Aug 28, 2011 10:31 PM in response to Eric Pensenstadler

It's for camers that shoot higher resolutions than yours does. So lets say your camera shoots 100mb/sec and ProRes Regular transcodes to 100mb/sec - good deal but if your camera shoots the same 100mb/sec and ProRes HQ transcodes at 1500mb/sec you have 1400mb/sec of useless empty space that FCP is processing needlessly.. Your original 100mb/sec isn't any higher quality. Hence the semi analogy. Those figures aren't real just for example puposes.

Aug 28, 2011 10:36 PM in response to poconorm

Huh, ok. I get it now.

Really appreciate your time.

poconorm

Level 1

95 points

Aug 28, 2011 10:43 PM in response to Eric Pensenstadler

He he, I'm getting tired too. Just stay away from HQ and you'll br fine. In fact if you're doing a lot of multi-cam LT will be easier and you'll be hard pressed to see the difference between regular and LT even on a Blu-ray

Aug 29, 2011 11:13 AM in response to poconorm

So I'm sure this will not be much of a surprise, but for those following this thread hopefully it will be helpful:

I L&T the ceremony portion again - 3 clips 43 minutes in length. With settings of ProRes422 HQ the files were approx 71GB. Transferring with ProRes422 setting files were approx 46GB.

I put both files - the HQ and regular - on top of each other and toggled back and forth between them while viewing on an HD monitor and saw absolutely no difference whatsoever. I rendered a short section of each, played them back in real time and again saw no difference.

The L&T time of the clip was just slightly better than real time (ie, 43 mintue clip took 35-40 minutes to transfer). I'd have to time the transfer of the same clip in HQ to see the difference, but I'm sure it's longer.

Oh, and NO dropped frames warning when playing back the 3 HD cams. I did, however, turn off the warning lastnight, but even still, it is playing back smoothly where as lastnight I still had to pause to let the computer catch up.

Hope this helps.

Eric

SLOW DISK warning on HD multiclip playback