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Dropping Frames during Capture

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Jeff Anderson
Dropping Frames during Capture
on Aug 17, 2010 at 3:37:26 pm

We are having capture issues with our Decklink HD Extreme 3D card dropping frames during capture of SD footage using the MJPEG codec. Our disk speed test shows that we have 274mb read and 100.7mb write. I don't think our storage system is the problem. Our computer is a HP Z800 and we are using the internal motherboard controller in a raid 5 configuration with 4 x 500GB seagate drives. The drives are only about 35% full so the overhead should not be an issue.

Also, we have had issues with the decklink card sometimes not passing video and we have had to reseat the card in the computer. Do you have any ideas what might be wrong?



HP Z800
Xeon 2.40GHZ
10GB Ram
Video Card: NVIDA GTX260
Storage: 4 x 500GB Raid5 using the HP motherboard controller.

Jeff Anderson


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Bob Zelin
Re: Dropping Frames during Capture
on Aug 18, 2010 at 1:20:50 pm

100MB/sec write is slow for 4 drives. A single modern SATA drive will give you over 70MB/sec, and two will do about double that. Something is wrong with your array.

Capture to an external firewire drive, and see if you have the same problem. You should get about 70MB/sec on an external FW800 drive.

Bob Zelin



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Joshua Helling
Re: Dropping Frames during Capture
on Aug 18, 2010 at 5:41:13 pm

Well, you're using a raid5 so your write speed is going to be slower than your read speed due to the controller having to write and distribute parity. But it should not be by 60%. I would expect if your read speed is ~270 then your write speed should be ~220. 100 is low for that raid, but it's not too low to capture motion JPEG. It's also not too low to capture uncompressed SD.

Most likely the reason for the difference has to do with some read or write caching being done by the Host Bus controller.

So as a test, try the capture as uncompressed. Does it work then? The reason I ask is because MJPEG is a fairly tightly compressed format and does require more CPU than hard drive power. If you find that you can capture SD uncompressed without issue then it is possible that the CPU is choking on that capture (though I wouldn't suspect that to be the case with your processor).

Sincerely,

Joshua
Director of Support
Blackmagic Design Inc.


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Jeff Anderson
Re: Dropping Frames during Capture
on Aug 18, 2010 at 6:38:04 pm

I have tried capturing using the 8Bit uncompressed setting and I still have dropped frames. It will capture for :10 to 1:00 of footage and then it will drop frames. Also, I have captured using Black Magic's Media Express instead of CS4 Premiere and I still get dropped frames.

I don't believe the raid drives are bad because I've used Windows disc check and Intels Raid Manager to check the drives for bad clusters and it passes the tests. As for system CPU resources when you capture and look at the Task Manager hardley any CPU or RAM resources are being used.

Does anyone have any ideas for what else we can look for to help solve this issue?

Jeff Anderson


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Margus Voll
Re: Dropping Frames during Capture
on Aug 18, 2010 at 9:05:19 pm

Some controllers are bad by default. They just are to slow because the way they are built.

--

Margus

http://iconstudios.eu


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Bob Zelin
Re: Dropping Frames during Capture
on Aug 18, 2010 at 10:04:23 pm

JEFF WRITES -
I don't believe the raid drives are bad because I've used Windows disc check and Intels Raid Manager to check the drives for bad clusters and it passes the tests. As for system CPU resources when you capture and look at the Task Manager hardley any CPU or RAM resources are being used.

REPLY -
you are WRONG. You own a Blackmagic card, and you should use Blackamgic speed test. And you can use AJA System Test (for Windows, not MAC). Or you can use HD_Speed from Steel Bytes, which is what AVID uses.

http://www.steelbytes.com/?mid=20

I have asked you to do a test with an external array, like with FW800, but I know what is going on here. You don't have an external drive, you dont' have an eSATA card, and you don't have an external eSATA drive. Your problem is your DRIVE ARRAY. You are using Intel's raid manager, which means NOTHING. You will solve nothing, and continue to blame Blackmagic for making crap products, when this has nothing to do with your problem. Pull out the Blackmagic card out of your computer. Go to Control Panel>Add/Remove Programs and uninstall the Blackmagic driver. Play back your video. It will STILL FAIL. Your problem is your drive array. who told you to build an internal RAID with the LSI Logic SATA controller inside your Z800. AVID knows very well that is it a piece of crap, which is why they specify the ATTO R380 card with an EXTERNAL ARRAY for the Z800 (they use AIC SAS/SATA chassis).

Everyone is going to be polite to you on this forum, but I will not. your problem is your drive array, and the tests you are doing are meaningless. It's your drive configuration. You want me to fix it for you - I can't. Buy the right gear. You have the best PC on the market - the Z800, but it can't do everything. Get a decent external array with an ATTO R380, or Areca 1680x, and you will have no issues (and you can use your existing 500 Gig drives to build this array).

Bob Zelin



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Jeff Anderson
Re: Dropping Frames during Capture
on Aug 19, 2010 at 4:16:44 pm

Yes, I did use the Blackmagic speed test and that is how I arrived at the numbers (274mb read and 100.7mb write). I am trying to figure out WHY the internal raid controller on the motherboard worked for the past 6 months with no problems at all until last week. It sounds like we'll have to purchase a good external controller to resolve the issue. The raid was built internally by the integrator to save us dollars but now its costing us productivity. Thank you for your input.

Jeff Anderson


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Bob Zelin
Re: Dropping Frames during Capture
on Aug 21, 2010 at 2:21:04 am

if things worked in the past, but now things are not working (and slowing down), it's because one of your drives is starting to become flakey and fail. Of course, you have no diagnostics with the LSI Logic RAID controller that is native to your HP Z800 motherboard. When you put on an external RAID controller and an external box, you will have DIAGNOSTICS to show you what is happening - you might even see that one of your drives has failed already. This is just one of the differences between professional robust SAS/SATA host adaptors, and the cheapos that can kinda get the job done. They work at first, but when you develop a problem (which you have), you have no diagnostics to figure out why your system isn't working.

No one ever gets to save any money - NONE of us. We all get screwed in the end. And then in a couple of years, all the computers and drives become outdated, and we have to start all over again. Welcome to the club.


Bob Zelin



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George Sey
Re: Dropping Frames during Capture
on Aug 21, 2010 at 2:18:42 pm

I am having the same problem on my oldest pc. The raid with the 500 drives are failing as they grow old whiles I have no problem with the Itb raids. The outdated drives in your set-up are failing. Consider update with new faster ones


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