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Capturing 1080p into FCP problems
Hi!
I am trying to capture some footage shot at 1080 psf 23.98, using a Kona3 card, going into a FCP5.1 system. The system is a G5 quad, 2GB RAM, and using an XServe RAID for storage(3.5TB all the drives on one side).The problem is, the footage captured looks like its dropping frames when played back. I’ve looked at the Quicktimes in the capture scratch and they appear to be dropping frames also.
Has anyone seen this problem before? My instinct tells me that it is dropping frames on capture, most likely because of the storage system.
Any thoughts?
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12 Replies
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[moodyglasgow] “My instinct tells me that it is dropping frames on capture, most likely because of the storage system.”
Follow your instinct.
What codec are you capturing to?
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[JeremyG] “What codec are you capturing to?”
AJA Kona 3 1080psf 23.98 uncompressed 8bit
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Okay, download and install the F_R_E_E Kona System Test and run a 4GB file on your RAID @ 1080p23.98 resolution and tell me what the overall read and write speed is when it’s finished in the upper right corner of the System Test window.
https://www.aja.com/ajashare/AJA_KONA_System_Test_v2.app.tar
Jeremy
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Understand that you need a minimum of 4 Sata drives grouped together in raid 0 to even be close to the data rate needed.
what does the System Test tell you.
gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows -
Yes, trying to capture 1080 24p or psf on only one Xserve Raid is a little too close for comfort. I’ve been able to do it to a 8-drive SATA raid with easy (400MB/sec+). That was until the raid crashed:(
Do you have “Abort capture on dropped frames” selected in the user preferences? This will let you know right away when you’re capturing if there is an issue.
And just to sound like a broken record, what did the AJA test say?
-Russ
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I ran an AJA test and got 160MB/s write speed, and 92 MB/s read speed.
I looked at the clip in FCP and in the quicktime player, and the skipped frames happen in the exact same spot. In FCP, it repeats a frame for 3 frames then skips ahead. In the quicktime player, it just skips ahead.
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Yep, that’s too slow. There’s some tweaking you have to do to an XServe (something about Host Cache flushing). I don’t remember off the top of my head. You are going to need to be running around 150MBsec or more to sustain uncompressed 1080p.
Hopefully someone with an XRaid can chime in and get your the correct settings.
Jeremy
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Found it:
“Using with Xserve RAID
If your Final Cut Pro workstations are connected to Xserve RAIDs either directly or via a fibre channel switch, ensure that each Xserve RAID has been configured in RAID Admin to have the option to “Allow Host Cache Flushing” to be unchecked.” -
Yeah I have Host Cache Flushing turned off.
Since it appears to be a raid speed issue, here is more info on our raid setup. We have an Xserve Raid, but we are only using one side. (not my choice). We have 7 500GB drives, running Raid 5.
So, I think to run uncompressed 1080p, we would need to use both channels on the fibre card. Any thoughts as to what format we could run with this current setup? I tried 1080p DVCPro HD, and that worked. I’m not thrilled about using that format, but this project is a freebie, so I’m not going to lose too much sleep over it.
BTW, thank you all for the help!
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Days like this you wish FCS2 was already shipping. This is a perfect example of where ProRES 422 is ideal.
DVCPROHD isn’t a bad option. It’s not the best option, but it isn’t bad. You might be able to use some PhotoJPEG settings that look as good as DVCPROHD if not better at some good data rates, but I know very little about using PhotoJPEG for that.
-Russ
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