Configuring a MacPro for uncompressed HD video capture and editing

March 1, 2007 11:44 AM

Help me configure a MacPro for uncompressed HD video capture/editing

I'm thinking about buying a Mac to capture (via HDMI) and edit 1080i HD video using a BlackMagic Intensity card. I would be using a Sony HDV camera and running an HDMI line from the camera into the Mac. The Mac would be configured as follows:

MacPro G5
- 2x 2.66 Xeon Processors
- 4 GB RAM
- 4x 750GB 7200 RPM SATA hard drives (with the 3 extra configured as a striped RAID)
- GeForce 7300 GT 256MB video card

In connection with this, I have a couple of questions:

- Apple claims that three internal 7200rpm drives striped together can deliver data rates up to 174MB/sec. The Blackmagic Intensity manual claims that the data rate of uncompressed 1080i footage is 120MB/sec. This makes me think that I could capture uncompressed 1080i footage without an external RAID - is this correct?

- As configured above, does my MacPro appear to be lacking anything as a high-end HD video editing station (other than the ability to drive two very large monitors)?

posted by dbolll to technology (11 comments total)

You don't really mean G5.
posted by ikkyu2 at 12:09 PM on March 1, 2007

that's a pretty cool looking card, I've actually wanted something like that for a while.

anyway, I edit uncompressed 1080i/720p video on my Mac Pro with the same specifications as yours without trouble. the realtime HD stuff in final cut works great (make sure you choose a standard HD size from the sequence settings dialog.) you SHOULD be able to capture video on your software RAID, though keep in mind your bus/cpu will go nuts during the process and you probably won't be able to do much of anything else. I can't confirm that it works firsthand but I don't see any reasons why it wouldn't (someone who has tried this or something similar will hopefully post.)

two things you might want to keep in mind: a better graphics card can make realtime compositing/effect operations much faster. you can buy a non-mac ati X1900 XT 512mb and flash it to work with mac/EFI, which enables you to get the card without paying the apple tax. you have to buy the 512mb version, though, not the 256 or whatever. google has more info.

the other thing: if your 750gb drives are seagate barracudas, they ship with jumpers on them that cap the bus to 1.5gb/s. take them off and you might get a tiny bit of performance improvement.
posted by tumult at 12:13 PM on March 1, 2007

Presumably you've read this tech note on the BlackMagic support page?

Blackmagic Disk Speed Test reported about 170 MB/sec which was easily fast enough for HD uncompressed 10 bit. However this three-disk internal solution is more suited to people needing simple capture and playback of HD, such as designers and effects artists. They just want simple clip capture and playback and the built-in three-disk array is a great solution for them. There are also newer 750 GB disks, which are faster, and so performance could increase further.

For editors who have hundreds of cuts and/or effects in their projects, we would strongly recommend an external disk array with multiple disks.

That's a test done with the setup you're mentioning (you don't mean G5; the G5 was an old PowerPC architecture, and you mentioned the Intel Xeon, which is the newest and greatest thing that Apple is selling right now.) So as near as I can tell, BlackMagic is saying that this setup works for what you want to do, but if you really want to edit a lot, you'll need an external fast RAID.

When you go to that page, by the way, ignore the section on PowerPC G4 and G5, as it's not pertinent to your setup.
posted by ikkyu2 at 12:21 PM on March 1, 2007

i just realized you hadn't ordered it yet. don't order the hard drives or the RAM from apple, they rip you off. owc is the place to go for RAM, and newegg will get you the hard drives much cheaper.

if you want to make your RAID more reliable and take stress off of your computer, you could also get a SATA II hardware RAID PCI-E card and hook the drives into that. it would be faster and more reliable than software RAID, and the cards are relatively cheap (compared to the rest of the system, anyway.)
posted by tumult at 12:26 PM on March 1, 2007

and yeah ikkyu2 raises a good point – i recommended a RAID card but a dedicated external solution really would be a whole lot better. i get by with a couple of internal drives, but if you're really serious about this, you might as well look into it, as you're already spending a buttload of cash on this setup.
posted by tumult at 12:33 PM on March 1, 2007

You want an external RAID, I think. I can't imagine the system is going to be very happy if you have the applications / swap / system on the same volume that you're using to capture to.

There are some nice ESATA hardware RAID boxes that you might want to look at. I don't know if they're fast enough for uncompressed video, but they might be worth looking at. Basically boxes that hold a bunch of drives, and then do hardware RAID and present themselves to the computer as a single striped volume, over ESATA. Basically they put the RAID hardware on the drive end of the interconnect instead of in the chassis.
posted by Kadin2048 at 12:44 PM on March 1, 2007

Thanks for the answers, they've all been great so far.

With regard to the external RAID suggestions, I'm aware that it's a better solution, but I worry that I would end up spending two buttloads of cash (to use tumult's quantification) to get the Mac and a decent external RAID.
posted by dbolll at 1:27 PM on March 1, 2007

You'll only be able to play one track of uncompressed HD (don't worry about 10 bit - this won't work.) You'll need to double that if you want to play a simple dissolve. An XServe, or other external raid is needed.

Out of curiousity - what is it that you uncompressed HD for? Why not work at DVCPROHD?
posted by filmgeek at 1:41 PM on March 1, 2007

What filmgeek said.

You don't want uncompressed HD - especially if you're acquiring in HDV. You should edit in the plain ole vanilla HDV codec, uprez to DVCProHD if you're feeling especially, you know, 'spicy'.

And for that, your base system is just fine. As you said, get the BM card, raid your internals, and you will be set.

There is no way you'd be doing editing in uncompressed HD unless you are doing a film-out, which is a completely whole different ballpark.

You're not doing a film-out, are you?
posted by jazzkat11 at 6:25 PM on March 1, 2007

i can play back a couple of HD 720p tracks at the same time off of one hard drive. it drops some frames or scales the resolution down if there are a lot of tracks/effects but it's not a big deal just for rough, realtime playback. I mean, you're going to be losing some frames during the realtime HD effects anyway. it's the capturing that needs to not mess up.

but yeah, you might want to play with some of the compressors to see if you can squeeze some performance out, depending on if your bottleneck is your hard drives or your cpu/gpu. compression will push some of the burden from the hard drives over to the cpu. there's a little bit of a quality hit, too, but it might be worth it.
posted by tumult at 6:33 PM on March 1, 2007

By the way; I know your'e doing this yourself....

but ProMax and Tekserve are Apple's key video VARs. They'd keep you from making mistakes for what you want to do.
posted by filmgeek at 4:40 AM on March 2, 2007