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Multiclip troubles – continually dropping frames
Hi All-
I’m having a new problem editing multiclips. When playing back the
timeline, I’m getting the Dropped Frames warning, with the red text that
says “RT Extreme has determined these dropped frames were caused by slow
disks. Please try:
-Increasing the speed of your disks.
– Decreasing the number of RT layers.
– Limiting your RT bandwidth in User Preferences.”What’s confusing is that this used to work fine. Here’s the specs:
2 x 3 GHz Quad Core Intel Xeon (Late Summer 2007 era model)
OSX 10.5.7
16 GB RAM
4 x 750 GB Hard drives – came with system – 3 Gigabit drives
Injesting material from HDV via AJA IoHD to Prores 422 (not HQ)
3 clips in the multiclip, each at 1280×720, 59.94, ProRes 422, each around
16 MB/sec.
FCP 6.0.6
OSX 10.5.8When I play one at a time, they are fine. It’s only when I start to play
more than one that I get this problem. That said, since we’ve been using
ProRes, I’ve NEVER been able to play all three at 100% quality, I always
have to take the RT quality menu down to QUARTER frame rate. But, again,
that used to work, but doesn’t any longer.Without multiclip, I have to edit these manually, using three tracks, and
that’s a pain!I don’t know that the problem is limited to multiclip playback, though. I
have noticed that I’m dropping more frames than I used to. Even after a
fresh restart… I’m still running into problems when playing back anything
that’s not a “blue” render bar. (In other words, if it’s “green”, I will
usually have to render it before I can play it, or it will drop frames and
stop.) So I’m not so sure this is a problem with Multiclip, as just a problem with my machine being able to play anything that doesn’t have a fully rendered bar at the top.Any ideas on what I may have inadvertently changed? Thanks for any help you
can give.-Carl Sundermann
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11 Replies
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Are those 4 drives raided together or JBOD?
3 streams of 720p59.94 ProRes is coming close to maxing out a single drive.
Jeremy
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Are all the (4) drives internal and RAIDed together, so your your media and your system is all all the same RAID? if so that is bad, very bad.
If not how full are the drives? these should never be more than 80% full. and should be reformed and re-stripped after major projects.
A quick fix maybe to low the framerate in RT off of Dynamic, quality is processor speed, framerate is drive speed, you can normal do the rough edit with choppy video and then when you do to fine tune the edit you can collapse the multicam and it should be fine to bring the framerate back up.
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Hi Jeremy –
No RAID set up here. The 750 GB drives are operating independently as: 1)System 2)Project Files 3) a nightly backup of Project Files 4) Media.
You say playing 3 streams is close to maxing out the drive… While I can’t entirely say that I understand the math here, I can tell you that I’ve been doing it for approx 6 months, and then suddenly I’m having problems. So it’s not that i’ve NEVER been able to do it… All I had to do was take down the frame rate to QUARTER and it was good. So that’s why I feel like something changed. I’m still on FCP 6… Maybe this is a bug they fixed in 7?
Other ideas? Thanks!
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[Carl Sundermann] “While I can’t entirely say that I understand the math here, I can tell you that I’ve been doing it for approx 6 months, and then suddenly I’m having problems.”
Allow me.
On a totally empty SATA drive, let’s say you can get 68MB/sec. As that drive gets more full, it will slow down, this is the nature of a spinning platter.
So, one stream of ProRes @ 720p59.94 with 2 channels of 24bit audio will run you 21MB/sec according to the AJA Data Rate calculator. Multiply that by 3, that’s 63MB/sec. Add more audio, overhead and processing, you are very close to maxing out that drive, especially as it fills up and fragments.
Stripe two drives together and you can do this no problem, but when striping two drives together, you will lose the current media on them so be sure to back it up before the stripe.
Jeremy
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[Jeremy Garchow] “So, one stream of ProRes @ 720p59.94 with 2 channels of 24bit audio will run you 21MB/sec according to the AJA Data Rate calculator. Multiply that by 3, that’s 63MB/sec. Add more audio, overhead and processing, you are very close to maxing out that drive, especially as it fills up and fragments. “
Very helpful! So a couple follow up questions…
FCP says my clips are approx 16 MB/Sec. That’s approx 48 MB/Sec. Even as my drive gets full, could it really not be able to keep up with 48 MB/Sec? Even when I lower the frame rate to quarter?
Is there a way to test what speed my drives can handle?
Currently my media drive has over 200 GB free on a 750 GB drive. However, I’ve also had this problem after I’ve just cleaned off that drive. That said, I did not ERASE it, just deleted items. Should I use the disk utility “ERASE” function? Is that the preferred method to clear the drive? If so, and since I haven’t ever done this, it’s making sense that this could be contributing to my issues…
When striping… Is the easiest way to do this using Disk Utility? (of course assuming I back up all data, etc…)
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[Carl Sundermann] “FCP says my clips are approx 16 MB/Sec. That’s approx 48 MB/Sec. Even as my drive gets full, could it really not be able to keep up with 48 MB/Sec? Even when I lower the frame rate to quarter? “
Carl,
Pardon my being blunt, but like a lot people, you are looking at the hard drive throughput equation totally “bassakwards,” from the standpoint of, “what can I squeak by with” and still get my work done. That approach is a recipe for insanity, because you’re always living on the edge, wondering exactly when your system is gonna let you down.
The secret, and it doesn’t have to cost a lot of dough, is to simply be smart about it, and stripe enough drives together in a raid to give yourself the extra overhead necessary to achieve more throughput than you might ever need, and the peace of mind that comes with it.
Hard drives are cheap Carl — a raid-0 and a BU setup means a whole lot of peace of mind at a very low cost.
And, yes the Apple Disk Utility is the easiest way to create a striped set/raid.
David Roth Weiss
Director/Editor
David Weiss Productions, Inc.
Los AngelesPOST-PRODUCTION WITHOUT THE USUAL INSANITY ™
A forum host of Creative COW’s Apple Final Cut Pro, Business & Marketing, Indie Film & Documentary, and Film History & Appreciations forums.
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Hi David –
I have no problem with “bluntness”. I grow weary of those who dance around the issue without just saying what’s on their mind. So no offense taken… I know you’re just trying to help. That’s what the cow is for. Just don’t take any offense to my response!
[David Roth Weiss] “… you are looking at the hard drive throughput equation totally “bassakwards,” from the standpoint of, “what can I squeak by with” and still get my work done. That approach is a recipe for insanity, because you’re always living on the edge, wondering exactly when your system is gonna let you down. “
Actually, no. I don’t believe I’m looking at it that way. And like you, I don’t believe in working “on the edge wondering when the system is going to let me down”. However, I AM trying to make myself educated on this issue. I’m not asking the question “what’s the least I can get by with”, but rather, what do I need to accomplish this without going overboard? Why buy a car with a V8 engine, when all you’re pulling is a bike rack? (I’m no good at coming up with analogies, so I hope you at least understand what I”m trying to say…) 🙂
I’ve never worked with a RAID setup in a computer before, and no one else in the office has either. And, since my setup has been working without issue (until now) I didn’t have any reason to question my existing setup. (Which also begs the question… Why did it work until now? From what I’ve learned in this thread so far, I’m assuming the answer is fragmentation. Yes?)
That said, I’m certainly willing to change, and give the RAID a shot. So let me ask this… If I use Disk Utility to create the RAID, what configuration would you recommend? Remember I have 4 drives. Currently I’m set up like this: 1) System 2) Projects 3) Projects Backup (SuperDuper copies new information to this drive nightly) 4) Media. I also have a USB hard drive that SuperDuper also copies the system drive to each night, in case I would have a failure on drive 1. Would you recommend I RAID the Projects Backup and Media drives as one, then buy another USB hard drive to back up my projects to?
Also, is there a way I can tell what kind of throughput I’m getting on my drives? I’d like to compare the way it’s currently set up, and how it changes when I put the drives in the RAID. Any other web links I can look at to learn more about what’s happening in the RAID setup?
As always… Thanks for the help. Feel free to be blunt any time.
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[Carl Sundermann] “Currently I’m set up like this: 1) System 2) Projects 3) Projects Backup (SuperDuper copies new information to this drive nightly) 4) Media. I also have a USB hard drive that SuperDuper also copies the system drive to each night, in case I would have a failure on drive 1. Would you recommend I RAID the Projects Backup and Media drives as one, then buy another USB hard drive to back up my projects to? “
The way you have things set up now is all about backups, not performance, and the system drive is really where your projects should be stored.
If your machine is essentially a dedicated editing machine, and you want to use just the four onboard drive bays to your greatest advantage, it behooves you to set up those drives for both performance and storage space, using outboard drives for backup. The reason for this is that your realtime performance and thus your experience in day to day editing is improved dramatically by increasing throughput, and throughput is a factor of storage space and the number of drives striped together in a raid.
So, while there is a solution for adding a fifth drive to the unused optical bay, for now we’ll just assume you are going to use one of your four internal drive bays as your system drive, and the other three internals should be striped together as Raid-0. Striping three drives together increases throughput by nearly, but not quite, 3X the speed of a single drive. You can test that using the AJA system test that downloads with the Kona drivers and codecs from their site. While three drives striped together may sound like overkill, it’s just a good start. You’ll want an eight bay raid soon enough once you realize how much better your editing system will run with only three drives as raid-0.
Gotta run…
David
David Roth Weiss
Director/Editor
David Weiss Productions, Inc.
Los AngelesPOST-PRODUCTION WITHOUT THE USUAL INSANITY ™
A forum host of Creative COW’s Apple Final Cut Pro, Business & Marketing, Indie Film & Documentary, and Film History & Appreciations forums.
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[Carl Sundermann] “Even as my drive gets full, could it really not be able to keep up with 48 MB/Sec? Even when I lower the frame rate to quarter? “
OK, that’s 48MB/sec with your movies fragmented all over the drive. Yes, it’s possible. Again, 3 streams of 720p60 ProRes is pushing the upper limit of one drive.
[Carl Sundermann] “Is there a way to test what speed my drives can handle? “
AJA has a free speed test, but really, you should get another drive and stripe them together. Multi-stream playback requires fast drive throughput with plenty of overhead.
[Carl Sundermann] “That said, I did not ERASE it, just deleted items. Should I use the disk utility “ERASE” function? Is that the preferred method to clear the drive?”
So when you drive is getting and full and you simply erase the drive, it’s not like taking out the garbage. When you take out the garbage, you are simply removing space from your waste can to be refilled with more waste from the bottom up. Or let’s say you take some garbage form the bottom, the stuff that was on top will now fill that empty space on the bottom leaving room for more garbage on the top. Now that I have compared media to garbage, hard drives don’t have this method of gravity, so they simply don’t work like that. When you delete a file, you are basically deleting a pointer to the media and leaving holes all over the drive. Then as new files get written to the drive, they simply fill up those holes. They could be big, they could be little, they could be miniscule. But now any new big files written to that drive will be fragmented and all the other files that are on your drive will compete with reading and writing.
You have the drives now to do what you want to do. It’s up to you to do it.
Jeremy
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David, thanks for the reply… Sorry for the delay in getting back to you, I was in the middle of a project. Now that I’m finished with that, I have a few other small things to finish up, and will likely get to setting up the RAID later this week.
I have a couple other questions about setting up the RAID, but I think I will start a new thread, as my original question in this thread has certainly been answered. Thanks!
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