Hard drive with sdi at DVinfo.net

Trevor Allin · July 15th, 2006, 04:52 PM

Hi

Anyone know of hard drives with sdi connectors that would not necessarily need to be connected to a pc etc. Basically to capture straight from the camera but at high quality?

Thanks

Trevor

Nate Weaver · July 15th, 2006, 05:28 PM

No such animal. Sorry :-)

SDI is a digital signal stream...but to write it to a disk there has to be some smarts about how it's done, how the data is arranged, etc. Heck, there needs to be a file system.

Hard drives have nothing of this sort built in. That is in essence what a Firestore does...takes an incoming bitstream and encapsulates it into files, and then runs that filesystem.

Trevor Allin · July 16th, 2006, 12:00 PM

Thanks Nate

I am clutching at straws! I am still trying some way to capture from the component out of my HD100 in such a way that I would not have to lug a pc everywhere.

Kind regards

Trevor

Nate Weaver · July 16th, 2006, 12:05 PM

Your brain is about 2 years ahead of current tech. There are devices that can do what you say (Wafian, etc), but all of them are still the size of a PC.

Charles Perkins · July 28th, 2006, 06:23 AM

i'm also looking for a device like this. if my maths is right, for HD SDI off of an xl-h1 you woudl need 500GB of space for an hour of recording?

Jerry Porter · July 28th, 2006, 07:02 AM

HDV Rack and a laptop not as small as a Firestore, but not exactly hauling an elephant around either. Plus if you capture to an external G-Raid drive you just unplug it and plug straight into your editor and go. That's the set up I'm in the process of putting together for my HD100.

Trevor Allin · July 28th, 2006, 09:39 AM

Hi jerry

The only problem with your solution is that is that you cannot connect to the component out of the HD100 and take it to a laptop for capturing through DV Rack.

The answer is out there somewhere!

Trevor

Jerry Porter · July 28th, 2006, 09:52 AM

I wonder if there is a componet card that will talk to HDV rack? Sound might be a problem though.

Keith Wakeham · July 28th, 2006, 06:41 PM

I've been involved with a project for a long time to do just this with FPGA's. Suffice to say that it is very complicated and really difficult to solve problems.

For instance, yes its over 500gb/hr - but you need to be able to record reliably at 150MB/s... for the entire drive, so only numbers that count are minimum sequential writes. And it needs to be rugged enough to sit on a camera, and reliable enough that a drive failure or 2 doesn't loss the data.

The only way I've found to do it so far is to keep winding up the number of drives. Only drives that have space and rugged enough are 2.5" so far. Reliable writing in PIO mode = 10 average drives + 2 parity, in uDMA 6 drives + 2 parity, but must be high end drives and 7200rpm so more likely to fail if camera mounted.

Lose your footing or a hard jolt and their goes a drive or two depending on angle, impulse force, head position, etc.

It can be done, but their are lots and lots of issues that need to be solved, which when i started on it I never foresaw.

I'm working on a different approach that won't throw away my last years work on embedded hard drive control. But either way, if you want fully uncompressed right now its big computer with 4-5 fast 3.5" drives or tape until you can get 250GB drives that can handle jostling that can sustain 80MB/s.

Trevor Allin · July 29th, 2006, 01:15 AM

Hi Keith

Thanks for this. I think the only way around the number of hard drives problem is to somehow use a lossless codec for recording. This is what the Bonsai drive does and works with one standard 7200 drive, but only for standard definition.

I am trying to look at the possibility of a small (as possible) housing for pc components with a capture card (Xena LH), and perhaps a programable key pad, using such a codec. And of course some kind of 12v dc supply!

I just don't know at this point how workable it would be so that you could somehow just "press record" when you need to. Some kind of program would need to be interacting with the card and lossless codec. And to add a screen would mess up portability and power supply I suspect.

It must be possible though!

Kind regards

Trevor

July 15th, 2006, 04:52 PM	#1
Trevor Allin Regular Crew Join Date: Sep 2005 Posts: 152	Hard drive with sdi Hi Anyone know of hard drives with sdi connectors that would not necessarily need to be connected to a pc etc. Basically to capture straight from the camera but at high quality? Thanks Trevor

July 15th, 2006, 05:28 PM	#2
Nate Weaver Wrangler Join Date: Oct 2002 Location: Los Angeles, CA Posts: 2,100	No such animal. Sorry :-) SDI is a digital signal stream...but to write it to a disk there has to be some smarts about how it's done, how the data is arranged, etc. Heck, there needs to be a file system. Hard drives have nothing of this sort built in. That is in essence what a Firestore does...takes an incoming bitstream and encapsulates it into files, and then runs that filesystem. __________________ My Work: nateweaver.net

July 16th, 2006, 12:05 PM	#4
Nate Weaver Wrangler Join Date: Oct 2002 Location: Los Angeles, CA Posts: 2,100	Your brain is about 2 years ahead of current tech. There are devices that can do what you say (Wafian, etc), but all of them are still the size of a PC. __________________ My Work: nateweaver.net

July 28th, 2006, 06:41 PM	#9
Keith Wakeham Major Player Join Date: Jan 2005 Location: St. John's, NL, Canada Posts: 416	I've been involved with a project for a long time to do just this with FPGA's. Suffice to say that it is very complicated and really difficult to solve problems. For instance, yes its over 500gb/hr - but you need to be able to record reliably at 150MB/s... for the entire drive, so only numbers that count are minimum sequential writes. And it needs to be rugged enough to sit on a camera, and reliable enough that a drive failure or 2 doesn't loss the data. The only way I've found to do it so far is to keep winding up the number of drives. Only drives that have space and rugged enough are 2.5" so far. Reliable writing in PIO mode = 10 average drives + 2 parity, in uDMA 6 drives + 2 parity, but must be high end drives and 7200rpm so more likely to fail if camera mounted. Lose your footing or a hard jolt and their goes a drive or two depending on angle, impulse force, head position, etc. It can be done, but their are lots and lots of issues that need to be solved, which when i started on it I never foresaw. I'm working on a different approach that won't throw away my last years work on embedded hard drive control. But either way, if you want fully uncompressed right now its big computer with 4-5 fast 3.5" drives or tape until you can get 250GB drives that can handle jostling that can sustain 80MB/s. __________________ www.engr.mun.ca/~wakeham/index.htm

July 16th, 2006, 12:00 PM	#3
Trevor Allin Regular Crew Join Date: Sep 2005 Posts: 152	Thanks Nate I am clutching at straws! I am still trying some way to capture from the component out of my HD100 in such a way that I would not have to lug a pc everywhere. Kind regards Trevor

July 28th, 2006, 06:23 AM	#5
Charles Perkins Regular Crew Join Date: Apr 2006 Location: paris, fr Posts: 102	i'm also looking for a device like this. if my maths is right, for HD SDI off of an xl-h1 you woudl need 500GB of space for an hour of recording?

July 28th, 2006, 07:02 AM	#6
Jerry Porter Major Player Join Date: Aug 2005 Location: Satellite Beach, Fl Posts: 784	HDV Rack and a laptop not as small as a Firestore, but not exactly hauling an elephant around either. Plus if you capture to an external G-Raid drive you just unplug it and plug straight into your editor and go. That's the set up I'm in the process of putting together for my HD100.

July 28th, 2006, 09:39 AM	#7
Trevor Allin Regular Crew Join Date: Sep 2005 Posts: 152	Hi jerry The only problem with your solution is that is that you cannot connect to the component out of the HD100 and take it to a laptop for capturing through DV Rack. The answer is out there somewhere! Trevor

July 28th, 2006, 09:52 AM	#8
Jerry Porter Major Player Join Date: Aug 2005 Location: Satellite Beach, Fl Posts: 784	I wonder if there is a componet card that will talk to HDV rack? Sound might be a problem though.

July 29th, 2006, 01:15 AM	#10
Trevor Allin Regular Crew Join Date: Sep 2005 Posts: 152	Hi Keith Thanks for this. I think the only way around the number of hard drives problem is to somehow use a lossless codec for recording. This is what the Bonsai drive does and works with one standard 7200 drive, but only for standard definition. I am trying to look at the possibility of a small (as possible) housing for pc components with a capture card (Xena LH), and perhaps a programable key pad, using such a codec. And of course some kind of 12v dc supply! I just don't know at this point how workable it would be so that you could somehow just "press record" when you need to. Some kind of program would need to be interacting with the card and lossless codec. And to add a screen would mess up portability and power supply I suspect. It must be possible though! Kind regards Trevor