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-   -   What exactly do capture cards do? (http://www.dvinfo.net/forum/high-definition-video-editing-solutions/90244-what-exactly-do-capture-cards-do.html)

Michael Richard March 29th, 2007 03:34 PM

What exactly do capture cards do?
 
DeckLink HD Extreme like this one.

What is it they do? Why would it be worthwhile to get one? Would it make editing easier, faster? Could someone explain in laymen's terms how these work. I edit in FCP btw. Do they always capture uncompressed video? Do you need special drives or are sata drives fast enough?

Douglas Villalba March 29th, 2007 04:11 PM

Quote:

Originally Posted by Michael Richard (Post 650996)

1. DeckLink HD Extreme like this one. What is it they do? Why would it be worthwhile to get one? Would it make editing easier, faster?

2. Could someone explain in laymen's terms how these work. I edit in FCP btw.

3. Do they always capture uncompressed video?

4. Do you need special drives or are sata drives fast enough?

1. I have this card. What it does is capture and play back. If you want to edit any form of HD you need a way of monitoring what your are doing, CC etc.

2. I edit on FCP also. You can capture from tape through component or SDI. In my case I capture from an HDV tape to different format (DVCPRO HD). You can also as I said before play back to monitor or to PRINT TO TAPE.

3. It could capture uncompress if you capture life from the component cables of an HDV camera or from a different format that recorded uncompress.

4. SATA drives are fast enough for compressed HD like HDV, DVCPRO HD, etc. For Full HD 720 or 1080 Uncompress you need at least a SATA Raid (a combination of 5 or more SATA drives that share the job load)

I hope this answers your questions

Dom Stevenson March 30th, 2007 01:17 AM

I capture from an HDV tape to different format (DVCPRO HD)
 
Douglas. I'm interested why you do this? I shoot in 25p and capture into FCP with the 108025p setting and it works fine. What are the benefits of your workflow?

Daniel Aleksic April 9th, 2007 09:40 AM

You have to draw a thick line between capture cards and actual editors. Capture cards or I/O card will be a basic device that allows your computer to bring anything other than iLink (or Firewire) into or out of your computer.

Realtime editing cards or Video cards (remember the one you hook your monitor up to is a Graphics Card) have certain components on it that will help you accelerate things like compression/decompression, effects, transitions, etc.

Check out the X2 card from matrox on the low end or the AXIO card on the higher end. Whereas you can do 2-3 layers of DV video with maybe 1 3D-DVE and a transition at the same time you can do (depending on your hardware) 7, 8 or more layers of Video with DVE's in realtime without the need to render.

I just finished an edit with the AXIO where I had a "Brady Bunch" type 9 way split and then the videos flew out of the picture at the end in 3D motion. So I had 9 layers of Video with 9 layers of 3D DVE's and 9 individual disolves running all in realtime. That is the power only a Realtime Video card can give you. Whichever way you go or whichever platform you use, remember, you always get what you pay for!

Adam Oas April 9th, 2007 01:53 PM

The layman's answer...

One big reason that you'll see people getting capture cards is that they need to import and export from or to things that don't have Firewire... such as a Beta deck.

In other words, if you don't need anything but Firewire I/O you don't really need a capture card.

If you do want to capture uncompressed you will need some sort of card (I have the Decklink HD Extreme) and you will also need a fast array.

John Hewat April 20th, 2007 09:12 PM

Quote:

Originally Posted by Adam Oas (Post 656879)
If you do want to capture uncompressed you will need some sort of card (I have the Decklink HD Extreme) and you will also need a fast array.

I have a question about that:

I'm looking into the Blackmagic Intensity HDMI capture card to capture uncompressed 1920x1080p from my V1.

I have two 250Gb SATA drives connected by RAID 0 (so says the guy who built my computer anyway - but as far as I'm concerned, disc to disc copying is SLOW as!).

Am I really going to need more than that to capture uncompressed?

Harm Millaard April 21st, 2007 03:06 AM

Quote:

Originally Posted by John Hewat (Post 664339)
I have a question about that:

I'm looking into the Blackmagic Intensity HDMI capture card to capture uncompressed 1920x1080p from my V1.

I have two 250Gb SATA drives connected by RAID 0 (so says the guy who built my computer anyway - but as far as I'm concerned, disc to disc copying is SLOW as!).

Am I really going to need more than that to capture uncompressed?

You need to capture BEFORE recording to tape, on location and you need at least a sustained write speed of minimum 125 MB/s. I expect you need at least 4 disks to achieve that. Another practical point is lugging your PC along with your camera and finding AC power out in the field. It somewhat hinders your mobility.

If you are thinking about capturing through HDMI what was recorded on tape, it will be heavily compressed 1440x1080 in 4:2:0 format and your disks are capable of handling that. But then using a simple fire wire would accomplish the same result. Where would the value added of the Intensity be?

John Hewat April 21st, 2007 05:12 AM

Quote:

Originally Posted by Harm Millaard (Post 664452)
You need to capture BEFORE recording to tape, on location and you need at least a sustained write speed of minimum 125 MB/s. I expect you need at least 4 disks to achieve that. Another practical point is lugging your PC along with your camera and finding AC power out in the field. It somewhat hinders your mobility.

I understand the need to capture live and that's not a huge problem for me. But the extra hard drives I'll need are a bit of a hindrance.

How does one set up a RAID array? When I bought the components of my PC and had it built I said I want RAID 0 and he said ok.

But how do I know if it worked? And how do I add another 2 disks?

Harm Millaard April 21st, 2007 05:43 AM

Quote:

Originally Posted by John Hewat (Post 664467)
I understand the need to capture live and that's not a huge problem for me. But the extra hard drives I'll need are a bit of a hindrance.

How does one set up a RAID array? When I bought the components of my PC and had it built I said I want RAID 0 and he said ok.

But how do I know if it worked? And how do I add another 2 disks?

The best way is to use a hardware raid controller, preferably from Areca, because they are really the best ones. While booting your PC you can enter the raid configuration utility and add disks to the array. You will lose all data on the current array, so better copy those to another drive before adding disks to the array and formatting the array.

The alternative is to use a software array under Windows, but that puts quite a strain on the CPU and is significantly slower than a hardware solution. The Help file will be a good source to start on how to do that. My experience is only with hardware controllers.

To check whether your disks have been properly configured, go to My computer and check the disk size. It should be around 466 GB. Installing 2 disks is really easy, open the case slide the disks into the cage, use 4 screws to fix them in each slot, attach power and SATA cables. Just make sure you get the same model and size you currently have.

John Hewat April 21st, 2007 06:41 AM

Quote:

Originally Posted by Harm Millaard (Post 664474)
The alternative is to use a software array under Windows, but that puts quite a strain on the CPU and is significantly slower than a hardware solution. The Help file will be a good source to start on how to do that. My experience is only with hardware controllers.

To check whether your disks have been properly configured, go to My computer and check the disk size. It should be around 466 GB. Installing 2 disks is really easy, open the case slide the disks into the cage, use 4 screws to fix them in each slot, attach power and SATA cables. Just make sure you get the same model and size you currently have.

Well my two disc drives are still listed separately in my computer.What good does a RAID array do for me other than capturing live footage? Maybe I should just disable it, if it is actually working...

Harm Millaard April 21st, 2007 07:26 AM

Quote:

Originally Posted by John Hewat (Post 664496)
Well my two disc drives are still listed separately in my computer.What good does a RAID array do for me other than capturing live footage? Maybe I should just disable it, if it is actually working...

In that case Raid0 has not been installed. For an explanation of what Raid does, look here: http://www.acnc.com/04_00.html

Windows will see a raided array as one disk, not as two or even more. The major benefit of a (R)aid0 - notice the R is really not available in a Raid0, since it lacks redundancy - is the improved speed. With 2 disk the speed of the disks is nearly doubled, with 3 nearly tripled, etc. However the major disadvantage is that if 1 disk fails, you lose the data on all your disks. No sensible person would go beyond 4 disks in a (R)aid0 array because of that risk. Most prefer to use Raid 5 or 6 for arrays with multiple disks, because then if 1 or even 2 disks fail (in the case of Raid6) you can recover all your data.

John Hewat April 21st, 2007 09:04 AM

2 Attachment(s)
Quote:

Originally Posted by Harm Millaard (Post 664513)
In that case Raid0 has not been installed.

I've just looked in my Control Panel at Computer Management and found this which lists drives D & E as Drive 0 with a capacity of approximately 470Gb.

Does that suggest that they are 'joined' but still separated? I'm a complete layman with all this stuff...

So am I right in assuming that (if Raid 0 is operational) I should have much faster transfer rates of files from D to E drive than to my system Drive?

Harm Millaard April 22nd, 2007 04:01 AM

Your drive contains 2 partitions, one of which is called Stripe1. Personally I never partition my disks and the name makes me wonder whether it is indeed a raid0 or a raid0+1. I would explicitly ask your builder what he has done. Alternatively you could run HDtach or similar disk testing program and see what your transfer rate is. If it is indeed a raid0, the results should be over 100 MB/s.

On second thought, it does look like it is properly formatted as a Raid0, since fault tolerance is off. The name of the first partition threw me off. Windows does see at as one disk, but with two partitions.

John Hewat April 22nd, 2007 04:05 AM

Quote:

Originally Posted by Harm Millaard (Post 665004)
If it is indeed a raid0, the results should be over 100 MB/s.

If that's the case then I can safely say that I do not have a RIAD0 setup.

Bugger.

Is HDtach something that is on my computer already or do I need to download and install it?

Harm Millaard April 22nd, 2007 03:52 PM

John,

Here is the link: http://www.simplisoftware.com/Public...request=HdTach

Run it on both of your disks and report the differences. Maybe I can figure it out for you.


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