Getting Dropped Frames and Freezes Capturing Uncompressed 1080psf 23.98

Blackmagic Design

Getting Dropped Frames and Freezes Capturing Uncompressed 1080psf 23.98

Posted by Robert Douglas on October 12, 2005 at 2:59 am

Hello everyone,

I am capturing uncompressed 1080psf 23.98 fps from an S-Two Digital Film Recorder with FCP 5.0 and a dual 2.5 gig G5, 8 gigs of ram and a Decklink Dual link HD Pro card in the PCI-X 100mhz slot. The S-Two DFR records 4:4:4 RGB as .dpx files and can also output dual link, 4:2:2 HD, analog RGB, and composite video. I use the FCP 1080p 23.98 10 or 8 bit easy setup and turn off every function that may cause FCP to drop frames or hangup. I can’t seem to get captures over 30 seconds that don’t drop frames or freeze the image for a several seconds before capturing normaly using “Clip, Capture Now, or Batch Capture”. Also everything that I do capture, either uncompressed or downconverted during capture needs to be rendered before it can be played back in real time.

I would appreciate any ideas as we have been experimenting with the audio/video settings, user preferences, and system settings.
Still Chipping away at it.
Cheers, Robert

Luke Maslen replied 20 years, 6 months ago 4 Members · 9 Replies
9 Replies

Kristian Lam
October 12, 2005 at 3:38 am

Hi Robert,

What other cards do you have in your system and is one of them in the other 100Mhz PCI-X slot?

What kind of storage array are you capturing to? Run Disk Speed Test and let us know the results.

Try capturing with Blackmagic Deck Control. Does that work?

“Also everything that I do capture, either uncompressed or downconverted during capture needs to be rendered before it can be played back in real time. “

Once you’ve chosen the easy setup in Final Cut Pro > Easy Setup, make sure you create a new sequence as your old sequences will still be configured using a previous setup.

regards

Kristian
Blackmagic Design
Robert Douglas
October 12, 2005 at 5:40 am

Hi Kristian,

Thanks for the reply. The other card in the system is a Mac fibre channel card. The disk array is an S-Two Dmag: Basically six Seagate 35 gig hard drives operating at 15k rpm configed into raid (not mirrored). When I am back at it tomorrow I will try all alternatives.

Thanks,
Robert Douglas
Robert Douglas
October 13, 2005 at 4:11 am

Hi Kristian,

I ran the Decklink disk speed test on our raid and the results were extremely poor. I then erased the raid and restripped it as Mac OS Journaled with 256k blocks, after running the disk speed test again it reads at 360 mbps and writes at 283 mbps. Input performance is noticeably improved, however capture still freezes randomly. I also noticed that if I run the speed test more than once on the newly striped raid the results can differ significantly. I have also used the Decklink capture tool with picture freezing and no timecode coming through as we are capturing our timecode via the RS-422 control.
Still Testing.
Cheers,
Robert
Kristian Lam
October 13, 2005 at 4:16 am

Hi,

What about the configuration of your card in the PowerMac? Make sure that the cards are not sharing the same bus, ie Slots 2 and 3.

regards

Kristian
Blackmagic Design
Robert Douglas
October 13, 2005 at 5:33 pm

Hi Kristian,

The Decklink card is in the 133 mhz PCI-X slot and the fibre card is next to it in the 100 mhz slot.
cheers,
Robert
Luke Maslen
October 14, 2005 at 7:00 am

Hi Robert,

Please ensure any antivirus software is disabled. Does it help if you drag your disk array and/or your system disk in to the privacy area of the Spotlight Prefpane?

Regards,

Luke Maslen
Blackmagic Design
Olivier Jean
October 14, 2005 at 10:11 am

Hi there,

you read and write should be pretty even,
what brand is your fibre channel, if it’s a Pci_X
card you should have it in the slot 4 which is
the PCI-x one the put the decklink card in the slot 3.

Have you any other cards in the G5 which model is it??

Like Luke said if you have anti virus get rid of it.

can you try to capture at low res to your internal hd and tell us what
happens??

Regards
Olivier Jean
Powermedia Systems
Sydney Australia
Robert Douglas
October 18, 2005 at 2:29 am

We did not have the raid set up properely. I set it up today as stripped array, Mac OS extended, and block size at 256k and it performed great. I also reinstalled all the relevent software after wiping the disk.
Cheers,
Robert Douglas
Luke Maslen
October 19, 2005 at 6:59 am

Hi Robert,

Thank you for letting us know the solution to your problem. RAID 0 is definitely a lot faster than RAID 5 although disk array manuals will often suggest RAID 5 as it offers some level of protection for your data should something go wrong with a disk.

The real test of any disk array is to see if its performance is still adequate when it reaches about 80% full.

Regards,

Luke Maslen
Blackmagic Design

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