Harddrive read/write speeds for video capture

[Cyber Akuma]

I tried to Google benchmarks on this but wasn't able to find any good results.

I want to know about harddrive read/write speed comparisons.

I can't afford SCSI drives, so, assuming all drives are SATA 3Gb:

And assuming one is using a good hardware-based raid card instead of the on-board motherboard raid (which I hear is software based and slower).

How much faster would a RAID 0 setup of 7200 RPM drives be compared to a single 7200 RPM drive connected to the motherboard?

How much faster is a 10,000 RPM drive to a 7200 RPM?

What about comparing a 7200 RAID 0 array to a single 10,000 RPM drive?

Is the speed of having two 10,000 RPM drives in RAID 0 worth it over a single 10,000 RPM drive?

The reason I am asking is because I want to buy this capture card:

http://www.blackmagic-design.com/products/intensity/

From what I understand, this is the ONLY capture card I could find that can capture in HD from HDMI or Component (And dosen't cost over $1000 with its intent being for professional studio work).

When capturing, I capture in RAW uncompressed format then encode it.

How much write speed would I need to ensure I can capture 1080P RAW video uncompressed without any framedrops? (I assume a modern i7 CPU based system should have enough processing power to pull this off?)

Would I need to have a separate scratch disk just for capturing?

I would prefer to use my OS drive, but with the OS and page file running off the same drive, somehow I doubt this would work no matter how fast I can make it will it?

If I have a RAID card that can support four drives, and make two seperate RAID 0 arrays on it (Say, one for my OS/page drive and one as a scratch array for video capture), would the use of one array effect the speed of the other?

[ajp_anton]

And assuming one is using a good hardware-based raid card instead of the on-board motherboard raid (which I hear is software based and slower).With raid0 there isn't much calculating needed, so a separate card is very much $ for very little.

How much faster would a RAID 0 setup of 7200 RPM drives be compared to a single 7200 RPM drive connected to the motherboard?In linear read/write, the speed of n drives is about n times 1 drive.


How much faster is a 10,000 RPM drive to a 7200 RPM?10krpm usually have smaller platters, and they probably don't use the latest in areal dencity. For good linear performance get a big 7.2krpm, for good access times get 10krpm.

Is the speed of having two 10,000 RPM drives in RAID 0 worth it over a single 10,000 RPM drive?Raid0 with 10krpm drives won't suffer from increased access times as much as 7.2krpm. You don't need good access times for capturing.

How much write speed would I need to ensure I can capture 1080P RAW video uncompressed without any framedrops? (I assume a modern i7 CPU based system should have enough processing power to pull this off?)1080p at 30fps in YUY2/YV12 needs 125/94 MB/s.
Core i7 should be fast enough for realtime lossless compression.

[Cyber Akuma]

1080p at 30fps in YUY2/YV12 needs 125/94 MB/s.
Core i7 should be fast enough for realtime lossless compression.

So you're saying that single 7200RPM drive dedicated just for capture would be more than fast enough to write 1080P in compressed RAW without framedrops?

[ajp_anton]

Maybe not "more than enough", and it depends on how well it compresses. Remember than the speed decreases in the inner parts of the disc.
You don't lose any capacity with raid0 so I would use that with two drives anyway just to be safe. Or you could try with one and if it's not enough or too close, buy another one.

[Blue_MiSfit]

I'd also steer you towards two 7200RPM SATA drives.

1080p is big, and you should really consider a good capture codec like CineForm or ProRes if you're on the mac. I don't know if HuffYUV or another lossless codec would be able to compress the video enough to stream capture to a 2 drive RAID.

~MiSfit

[easy2Bcheesy]

Buy the Intensity and CineForm NEO HD, which achieves anything from 8:1 to 16:1 compression with very little appreciable loss of quality. You'd be saving a huge amount of time and effort in transcoding files - it can capture in realtime on anything from a 2.4GHz Core 2 Duo upwards.

I would recommend a single OS drive and a single footage drive if using CineForm. A two disk RAID-0 array if you really need ultra-fast response during editing, but a single SATA Drive is fine.

If you're capturing 1080i60 uncompressed from Intensity you basically need throughput on your hard disk array of 122MB/s. Maintaining that throughput across the whole disk with no frame drops would be very challenging on a two disk array and you'd probably still be losing the odd batch of frames on a three disk array. And that's assuming you have something fast like Samsung F1 drives (I have four of these in RAID-0 myself).

If your data is important, CineForm would basically allow you to use RAID-1 or RAID-10, offering speed and security.

[Blue_MiSfit]

Well said!

The Intensity is a great little card, and CineForm is a perfect companion for it.

I know you can capture with Premiere or Final Cut on the mac, but can you capture with 3rd party utilities?

~MiSfit