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#1 DOsborne

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Posted 20 March 2006 - 05:07 AM

Ok so I've been thinking about getting a Decklink HD card. How fast of a hard drive would i need to capture 10 bit 4:2:2 uncompressed data? What about for 8 bit? I know that RAID set-ups are supposedly optimal but what about a single hard drive, are there any that are fast enough.

But uncompressed HD files are huge. Yeah I know, dang it all, but what if i got a 500gb drive or something like two 400 gb drives, 7200 rpm, is a data rate of 150 MB/sec. good enough, for capturing that is. What I'm thinking about is capturing mamoth sized uncompressed files, or maybe mildly compressed files and then creating much smaller duplicates to do something like an offline edit, so I wouldn't need a disk array to blaze through a terabyte of my lame footage on a whim as I search for good takes., but it would be there once I'm satisfied with my editing decisions.

How much is the cheapest RAID set-up? From what I've found 1.6 terabytes would cost me close to 3 grand, more than I paid for my dual processor G5 including the RAM upgrades and the monitor (granted i got a school discount but jeeeez).
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#2 David Cox

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Posted 20 March 2006 - 05:33 AM

150Mb per second would be right on the border of being able to take a 24P 4:2:2 HD stream. It would not take any greater frame rate.

The problem is that you need to have a good overhead on your disks, because otherwise if they don't "get there in time", you loose frames.

The deck-link cards are a good addition to the market, but the reason they are cheap is that they rely heavily on the host system. More expensive cards do more work on board. The result is that if your system is on the border of being able to cope, you will get lots of lost frames as your system does other things.

Also remember that the reason most pro installations use RAID is also to protect data. If you run off a single disk and it fails, you loose everything. And disks do fail when they get run that hard.

Lets go back a step - do you *really* need uncompressed? If you're not going back to film or very big screen projection, and if your project doesn't include lots of blue / green screen comps, then you might find that a good compression format will make surprisingly little difference to your final master, as viewed on a normal TV or large plasma screen.

The alternative route would be to edit compressed as you suggest, and create an EDL for conform and colour grade session at a post facility.

David Cox
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#3 Phil Rhodes

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Posted 20 March 2006 - 06:37 AM

Hi,

I tend to say about 180mbyte/sec for 1080 HD, which makes it necessary to aim somewhere north of 200 for any kind of reliability, but it's never going to be particularly cheap.

The cheapest way of doing it (at least doing it reasonably well) is with a 3ware 9000 series card (or two) and eight off the shelf SATA drives - could be put together for less than a grand. This of course presupposes that you have one or two free PCIe slots to host the boards, and a fast enough system to make everything else happen (A G5 should be OK).

Phil
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#4 Michael Most

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Posted 20 March 2006 - 09:46 AM

What I'm thinking about is capturing mamoth sized uncompressed files.....


And where exactly is the VTR you're digitizing those "mammoth sized" files going to come from if you can't afford $3000 for a disk array?

How much is the cheapest RAID set-up? From what I've found 1.6 terabytes would cost me close to 3 grand, more than I paid for my dual processor G5 including the RAM upgrades and the monitor (granted i got a school discount but jeeeez).


I really don't understand why you seem to think professional level HD post equipment should be affordable for students on their personal systems. There's an entire industry devoted to proper maintenance and use of high end equipment. Why not consider finishing at a facility built for and dedicated to this purpose? And please don't make this a financial issue. If you can't afford to do a high end HD production, don't do it. I'd like to drive a Ferrari but I don't because I can't afford one. If you don't have the budget to do what you "want" to do, do something else. My guess is whatever market you're trying to hit with these projects will be just as well served with standard definition DV as they will with what you're talking about.
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#5 Chris Burke

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Posted 20 March 2006 - 11:53 AM

Ok so I've been thinking about getting a Decklink HD card. How fast of a hard drive would i need to capture 10 bit 4:2:2 uncompressed data? What about for 8 bit? I know that RAID set-ups are supposedly optimal but what about a single hard drive, are there any that are fast enough.

But uncompressed HD files are huge. Yeah I know, dang it all, but what if i got a 500gb drive or something like two 400 gb drives, 7200 rpm, is a data rate of 150 MB/sec. good enough, for capturing that is. What I'm thinking about is capturing mamoth sized uncompressed files, or maybe mildly compressed files and then creating much smaller duplicates to do something like an offline edit, so I wouldn't need a disk array to blaze through a terabyte of my lame footage on a whim as I search for good takes., but it would be there once I'm satisfied with my editing decisions.

How much is the cheapest RAID set-up? From what I've found 1.6 terabytes would cost me close to 3 grand, more than I paid for my dual processor G5 including the RAM upgrades and the monitor (granted i got a school discount but jeeeez).



What flavor of HD are you shooting? If HDCAM, then you will need to invest in a rather expensive RAID array. I recommend checking out Macgurus.com for very affordable SATA II raid solutions. If you are shooting and editing in DVCPro HD, then a simpler hard drive solution is for you. Technically, check the Apple website for more info, off the shelf SATA drives are enough for DVCProHD. You would not have to do proxy files, you can edit in the native format. In any case, cutting uncompressed HD at home is for the very brave. Yes the hard drive requirements are getting cheaper and more accessible, but how about the monitoring, color correction? All this adds up and is very expensive. In the end, the simplest way is best. Go with DVCPro HD, it is much easier to use and not a bad offline format for film.
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#6 DOsborne

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Posted 20 March 2006 - 02:29 PM

And where exactly is the VTR you're digitizing those "mammoth sized" files going to come from if you can't afford $3000 for a disk array?
I really don't understand why you seem to think professional level HD post equipment should be affordable for students on their personal systems. There's an entire industry devoted to proper maintenance and use of high end equipment. Why not consider finishing at a facility built for and dedicated to this purpose? And please don't make this a financial issue. If you can't afford to do a high end HD production, don't do it. I'd like to drive a Ferrari but I don't because I can't afford one. If you don't have the budget to do what you "want" to do, do something else. My guess is whatever market you're trying to hit with these projects will be just as well served with standard definition DV as they will with what you're talking about.


Hi thanks for the feedback guys. I wouldn't have a VTR that's the thing, the "mamoth sized files" would be generated as the result of capturing the stream coming in from a camera like the XL H1, via the HD-SDI output.

I understand completely that HD production, like film production, is an expensive business and I don't necessarily find it appalling that people at the student/independent level can't afford cutting edge technology but I'm trying to preserve the best image quality for my project with what I have. I don't have anything against finishing facilities, I'd love to be able to take advantage of working with some in the future but right now I really admire the work being done by the people at reel-stream, P+S Technik, Black Magic, etc. They spend time trying to innovate with what they have to get the best out of what they and we the student/independent producer have. I'm trying to do sort of the same thing, to a lesser degree and intellectual level, but I'm trying and the feedback that I get here is really helping me.

So to clarify, my arguably over the top idea was to capture the HD-SDI stream from an XL H1, It doesn't have to be uncompressed but I want to avoid the Mpeg-2 compression process. I wanted to just get/acquire the large, mildly or uncompressed files, not to edit with them. I don't presume that dropped frames are that much of an issue when you just refer to the original files (the ones that would be pushing the limits of my system) for rendering/outputting (as opposed to playing them back RT), but I could be wrong, am I?

I would edit "offline" by down-converting these files onto a different hard drive, with heavy compression and/or smaller dimesions.

If my shoot takes place in two primary locations, a lot of interiors that don't require large company moves, then having my camera tethered to my computer wouldn't be quite as ridiculous as it would be in other situations. Thus, if I could capture the higher quality stream coming out the back of the XL H1, why shouldn't I? I'm presenting the final "film" at the NYU film festival and others where, if I get the post production grants I'm applying for, I could then ressurect those original files and have a finishing facility[!] (I'm not being facetious) help me prepare the material for film out or an HDCAM-SR master or whatever. SD video simply will not do at these and other international festivals.

Sadly I can't originate on these mediums but I can preserve what I do get with minimal ammounts of compression. This is my goal. Would one of the "borderline" RAID set-ups listed above be able to help me acheive this goal? Thank you all again.

Edited by DOsborne, 20 March 2006 - 02:34 PM.

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#7 Valeriu Campan

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Posted 25 March 2006 - 09:23 PM

For a good compression codec check this one:
http://www.bitjazz.com/sheervideo/
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#8 Michael Collier

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Posted 26 March 2006 - 02:15 AM

If you want to do this for a bare minimum of cost then you have to build the raid assembly. dont worry, all those naysayers who believe you need a post facility are the same who are beholden to large budgets to make anything possible.

Fight the problem with intelegence and research, not a money wagon. You can set up a SATA raid assembly with just a few disks and a controller card. they have to be stripped, and the machine will read them as a one drive. 150/Mb sec, check that figure. it may be max throughput, not sustained and it may also refer to the megeBAUD, not megaBYTE, (a megabyte is 8times larger file) so check all the math and make sure you have 15-20% overhead to handle system slowdowns, esspecially if this is your only method of full quality HD capture.

Check out the supersmall barebones computers. they are cheap, fast and have enough room to store 2-3 hard drives. that and a small LCD monitor would be enough.
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#9 DOsborne

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Posted 06 April 2006 - 03:00 AM

If you want to do this for a bare minimum of cost then you have to build the raid assembly. dont worry, all those naysayers who believe you need a post facility are the same who are beholden to large budgets to make anything possible.

Fight the problem with intelegence and research, not a money wagon. You can set up a SATA raid assembly with just a few disks and a controller card. they have to be stripped, and the machine will read them as a one drive. 150/Mb sec, check that figure. it may be max throughput, not sustained and it may also refer to the megeBAUD, not megaBYTE, (a megabyte is 8times larger file) so check all the math and make sure you have 15-20% overhead to handle system slowdowns, esspecially if this is your only method of full quality HD capture.

Check out the supersmall barebones computers. they are cheap, fast and have enough room to store 2-3 hard drives. that and a small LCD monitor would be enough.


Hey guys, thank you so much again. I've been looking at RAID setups and the miniG has really caught my eye. They have a 4 drive 2TB tower that, if striped can maintain a data rate of something like 600 Mb/sec. All that and it's just around $2,000. They also have smaller TB models for closer to $1,200. Also they look like baby G5's which is sort of cool. I'll need to get a PCI-X SATA card but hey, this isn't so bad!

And Valeriu thanks for the codec recommedation.
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#10 Phil Rhodes

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Posted 06 April 2006 - 05:58 AM

Hi,

That rate off those drives will be RAID-0. If any one drive fails, you lose the lot. Avoid.

But look at it another way. If you are happy to send your material back to a facility to be output, you can produce an HD production on a computer without the ability to play it back - nobody said conforming had to be a realtime process. It almost never is anyway.

Phil
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