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How Much Speed for HD

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Mike Maloney
How Much Speed for HD
on Apr 5, 2009 at 5:49:01 pm

Assuming I've all the latest AJA codes for my LH card, I'm dropping frames in HD 24p frame, using the 720 59.57 to a point where I can't capture. I can down convert to the DVCPROHD720 codec, pull my video/audio, but the quality isn't there. I've been back and forth with a variety of codec (pulling off my JVC BR-HD50 deck). I know the culprit in the Medea Raid with SCSI into an ATTO card and it can't seem to handle the throughput. The Medea is older, admittedly, but has worked without too many problems for a long while. Staying in SD, the Medea is a workhorse.

I've read/considered the SATA G Raids. That seems counter productive to what otherwise works pretty darn well taking the component out of by BR-HD 50, don't need to go back to a firewire solution.
Is there good news or bad news on HD with the G Raid?

So, am I missing an elementary codec solution or am I just in need of new drives?

Mike Maloney
Maloney Marketing Group
maloneymarketinggroup.com
beartoothrecording.com
mmg.bz


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Richard chin
Re: How Much Speed for HD
on Apr 6, 2009 at 8:00:54 pm

I use a SATA II raid with port multiplication along with a Caldigit SATA II raid card and it works pretty good for me. I can't see myself going back to SCSI. Also with SATA III round the corner, SCSI really is not a good idea.




Richard
John 3:16



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Bob Zelin
Re: How Much Speed for HD
on Apr 6, 2009 at 8:15:11 pm

Richard is absolutely correct. If you have an AJA card in your system, you have the AJA System Test in the AJA Utilities folder. Run this test on your Medea drive array. If you are not getting above 70Mb/sec, you are screwed.

DVCProHD (the resolution that is native to the BR-HD50U) is only about 14Mb/sec, but to get SUSTAINED PLAYBACK so you dont' get dropped frames, you need much more than this. A single internal Modern internal SATA drives will typically do aroudn 70Mb/sec, so a single internal drive that would cost you about $100 would work for you. Your reaction (or your bosses reaction) is "but we paid $8000 for this unit when it was new". WELL I DONT CARE. Time marches on. Throw it in the garbage. Richard Chin has an excellent drive array, and even if you have NO MONEY, you can still afford a single internal SATA drive.

I dont' know exactly what MAC you have, but I suspect that if you are using SCSI (like an ATTO UL3D card with a Medea drive array), you may have an older G5 with PCI-X slots. You will find that external FW drive arrays will not perform as reliably as external SATA arrays, or even internal single SATA drives.

Just do the AJA System Test, and see what kind of speed results you get on your Medea.

Bob Zelin




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Mike Maloney
Re: How Much Speed for HD
on Apr 7, 2009 at 12:13:07 am

True enough. The Medea cranks just slightly over 100 MB/sec. The internal SATA drive does not quite hit 90 MB/sec. The AJA white paper suggests 150 MB/sec is necessary to push HD, so I'm apparently back on a course to duplicate Richard's system with the SATA controller and a different Raid configuration. Time for the old system to retire.

Thanks for the wisdom.


Mike Maloney

Mike Maloney
Maloney Marketing Group
maloneymarketinggroup.com
beartoothrecording.com
mmg.bz


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