Raid Solution with 170MB/s Minimum transfer rate?

meansizzler · 4 Sep 2007 at 16:46

New some recommendations on a raid solution as want to do some video capture at 720P and need at least 170mb/s minimum transfer rate, so need PCI-E based RAID controller + Hard drives, any recommendations?, 500GB at least for total RAID size is ideal.., want to keep this as cheap but fast as possible don't mind forking out £200 or os for the raid controller though as long as it does the job, will be using PCI-E x 1, and only X4 if I really need it...

rpstewart · 4 Sep 2007 at 17:14

170Mb/s write rates! That might take a bit of doing.

RAID0 is realistically your only option, to write to RAID5 at that speed would cost a fortune. Four decent disks should be enough to give you that although write speed benchmarks are tricky to find to confirm that. There are PCIe 1x controllers with 4 ports out there but for RAID0 you might as well go with an onboard solution if you've got enough SATA ports to run 4 disks in RAID0 and have the OS etc on a separated drive/array.

For drives either the WD AAKS series (the 750 if you can stretch to 4) or if you can find them the single platter 250Gb Seagate 7200.10 (you'd need to check the model numbers to make sure you get a single platter one) if you don't need a huge amount of space.

Energize · 4 Sep 2007 at 18:32

170MB/s! Are you sure? rgb-24 720p @ 30fps only needs 83MB/s, and on the fly lossless compression would reduce the bitrate by a massive amount.

helmutcheese · 4 Sep 2007 at 22:17

Does he mean MEGABYTES or MEGABITS cause he said Mb/Sec, also 720p would again be measured in Mb/Sec not MB/sec, thats way fast lol.

smids · 4 Sep 2007 at 22:31

That is at least a 4 drive RAID0. That will pretty much do it as you should get about 220MB/s with a RAID0 of 4 perpendicular drives using platters >166GB. That's pretty much the cheapest way of doing it.

meansizzler · 4 Sep 2007 at 22:44

Resolution*Colour Mode*Refreshrate = HDD Transfer Rate Needed
[1280*720 pixels]*[24bit]*[60hz]

now converting bits to bytes

1280*720*3*60 = 166MB/s

Capturing Uncompressed of course...

and Megabytes not Megabits...

Also 4 * HDD in RAID 0 should do it as 45MB/s Transfer rate * 4 Drives = 180MB/s, but that figure is not constant....need a minimum of 165, so 5 drives to be safe..., so single platter ones would be better?, if so Recommend a model?

Also Recommend a cpature card?

basmic · 4 Sep 2007 at 23:12

You do know that the frame rate for most UK TVs is 25fps?

1280 * 720 * 3 * 25 = 65.92 MB/sec

mosfet · 4 Sep 2007 at 23:24

basmic said:
You do know that the frame rate for most UK TVs is 25fps?

1280 * 720 * 3 * 25 = 65.92 MB/sec

No, the frame rate for PAL encoding is 25fps. For HD streams it is 30 or 60.

Edit: I stand corrected, it would appear that 24 and 25FPS are acceptable broadcast rates for 720 lines resolution, but 30 and 60 are more widely used.

Energize · 4 Sep 2007 at 23:30

60fps hd streams are interlaced though, each field is only 1280x360 so it's the same as a 30fps progressive video.

I'm not aware of any consumer cameras that are capable of capturing 720P @ 60fps.

In any case, using lossless compression would likely eliminate the need for any type of raid at all.

What camera do you have meansizzler?

meansizzler · 5 Sep 2007 at 06:29

I don't have a camera, capturing from a games console, and it's 1280*720P, so it's 60 frames per second since it is progressive...

mosfet · 5 Sep 2007 at 09:24

A capture card should do hardware MPEG-2 encoding which dramatically reduces the required bandwidth. A single consumer drive would then be adequate.

meansizzler · 5 Sep 2007 at 10:17

As I said Capturing Uncompressed, as I can control the bitrate when encoding at a later on stage, don't want mpeg 2 or any other on the fly hardware compression..

Would someone please refer back to the original question and post a solution, I hate when everyone goes off track..

Dutch Guy · 5 Sep 2007 at 13:29

Have you thought about what connection to use from the console to the computer?

meansizzler · 5 Sep 2007 at 13:53

Dutch Guy said:
Have you thought about what connection to use from the console to the computer?

As I said again, this is not about how I am capturing video, just a recommendation on a PCI-E controller and hard drives to achieve the 170mb/s transfer rate, why is everyone refraining from answering it?.

Dureth · 5 Sep 2007 at 13:53

meansizzler said:
Would someone please refer back to the original question and post a solution, I hate when everyone goes off track..

They arn't going offtrack, you have a problem and the easiest solution involves a bit of lateral thinking.

Why exactly are you against MPEG2 encoding on the fly? It would save you hundreds of pounds and if your just recording a feed from a games console then quality isn't going to be effected by it as the content itself will be very basic.

Just something to think about.

Energize · 5 Sep 2007 at 13:58

meansizzler said:
I don't have a camera, capturing from a games console, and it's 1280*720P, so it's 60 frames per second since it is progressive...

Well now you have finally explained what your source is I don't think there is any capture card that will capture 720p from a consoles outputs other than possibly this hdmi one http://www.blackmagic-design.com/products/intensity/techspecs/ and that only captures in the YUV 16-bit colourspace, and may not even work due to hdcp.

meansizzler said:
Would someone please refer back to the original question and post a solution, I hate when everyone goes off track..

If you want to spend hundreds of pounds on a controller card and hard drives when free lossless compression would solve the entire problem be my guest. Since your going to be transcoding later anyway, capturing in rgb 24 doesn't make any sense, mpeg4 codecs all use YV12 internally so your going to be losing half the colourspace anyway.

RaiderX · 5 Sep 2007 at 14:07

are you sure its not 170Mbps instead of 170MBps, as that seems a bit high, the bandwidth of 1080p is less than that and can be transfered down USB

Dutch Guy · 5 Sep 2007 at 14:12

Highpoint 4-port PCIe RAID card with 4 recent SATA drives should do it in RAID0

meansizzler · 5 Sep 2007 at 16:08

Dutch Guy said:
Highpoint 4-port PCIe RAID card with 4 recent SATA drives should do it in RAID0

The most usefull post I have, but need a total solution, guess no one on here as any experience in this area, for the last time, what capture device I use is irrelavent, and as for mpeg2 it is not up to you, i have my reasons, why are all of you so stubborn?...

meansizzler · 5 Sep 2007 at 16:11

Dureth said:
They arn't going offtrack, you have a problem and the easiest solution involves a bit of lateral thinking.

Why exactly are you against MPEG2 encoding on the fly? It would save you hundreds of pounds and if your just recording a feed from a games console then quality isn't going to be effected by it as the content itself will be very basic.

Just something to think about.

Distribution via WMV means it will play on nearly any without any codec needed, as I said first I want to control the bitrate, you do not even know what bitrate I want to use?.. most of them mpeg 2 hardware encoders are limited to 2/4mb/s where as I want ot go for 12-14, show me a card which encodes an mpeg 2 stream at 12-14mb/s in realtime?..., I doubt it...