7 HD's inside a mac pro

[GideonKiers]

Hello there,

I'm working on a theatre project which needs a 18,5 meter panoramic projection. There are quite a few approaches to tackling this challenge. Indeed, most of them highly speculative ...

The plan at the moment is to have 4 projectors, driven by two new 2,66 Intel macs and catalyst v4. Each mac 2 GB (4x512mb) ram and an ati x1900 grphx card.

The resolution on the media files should preferably be 1024x768, but could also be 768x576. Codec would be photo-jpeg at 60 or 70 %.

Setup for each output would be pretty standard, 2 layers of video and possibly a masking (grphcs) layer. Hoping to use the new seamless panorama features in v.4.

• First question : Would a 10k sata disk be fast enough to drive those ± 4 layers of video + 2 masking layers for each machine ?

• Second question : Would it be possible to do the 4 outputs from one computer with the ati card and two dualhead2go's ? It would mean ± 8 layers of 768x576 photojpeg 60% video to four outputs via one machine.

• Third question : In case the dualhead2go solution has a chance of working, would it be possible to use one large (3072x576) quicktime for the four outputs ?

• Last question : Not having to render masks into the quicktime(s) would save us _a lot_ of time. This would mean moving one or multiple masks over the four screens in real-time. Would this be possible in the dualhead2go option ?

That's it for now, am sure there are more issues to it though

Thanks !

Gideon

[samsc]

you want to do these things - you have to do a few tests for yourself.
there are too many variables - and some of the answers you will need to find for yourself.

see what works and what doesnt.

do you have a raptor to test?

[tharding]

"• First question : Would a 10k sata disk be fast enough to drive those ± 4 layers of video + 2 masking layers for each machine ?"

Don't forget that if you are using dual outputs as a opposed to the panorama option that "Use Layer" is the most efficient way to go.

That means that if you want the same clip on Output 2 as Output 1 you can "Use Layer" the number of the layer you are playing the clip back on for Output 1. (Hope that made sense!)

This should cut down your disk overheads considerably if you only need 2 layers of video and 1 x masking layer.

In my experience you would struggle getting 4 layers smooth of one Raptor.

Cheers

Toby

[samsc]

In my experience you would struggle getting 4 layers smooth of one Raptor.

Cheers

Toby

mine too.

but sometimes its best for people to find out for themselves.

[GideonKiers]

mm no let me make myself a bit clearer, 4 seperate outputs should make one big panorama. each output therefore would be unique.

That means that if you want the same clip on Output 2 as Output 1 you can "Use Layer" the number of the layer you are playing the clip back on for Output 1. (Hope that made sense!)

[GideonKiers]

fair enough, but unfortunately as usual there's no time or money to test things out really..

so let me rephrase my question. what (non-scsi and non-fibrechannel) harddrive configuration would advisable for the smooth playback of 4 streams of 768 576 photojpeg non-100% clips, from a macpro 2,66 with an ati x1600 card on two seperate outputs, each in a 1024 768 resolution ?

sometimes its best for people to find out for themselves.

[tharding]

Yes but you use one part of the same image do you not? That is how Watchout and other systems work. all you are seeing is a different section of the same image or clip.

When you use the new panorama functions you are essentially doing this. Your mask for instance would be a single file across 4 screens not 4 separate files.

I have a 4 x Raptor RAID that can give me 4 layers of DV but not 1024 x 768 Photo Jpeg without some dropped frames. As Richard says, you really have to try it. I have an Xserve RAID but I still have to check every combination I come up with.

Cheers

Toby

[GideonKiers]

Absolutely yes, each of the 4 projectors does 1/4th of the whole image.

I'm thinking of doing 768x576 photojpeg files, not 1024x768.

The advantage of doing 4 projectors from one machine is that you're working on the whole 'canvas' from one machine, therefore moving a mask around the whole canvas is much easier than if we would do it on two machines.

Maybe I'm misunderstanding you, but I don't really see why 4 layers of DV playback needs a 4 x Raptor RAID though ? I have an old 3.2 catalyst system here that plays 4 dv layers from one 7200 scsi disk without really any problems on a dual 2.5 ppc.

I find it a bit hard to believe that there's no other solution to my harddrive speed problems then buying the xserve raid ...
How about the Fujitsu MAU3147NP (Ultra 320) and an Atto PCI UL5D pci-e card. Would that be sufficient (theoretically) to drive 4 layers of either DV-PAL or 768x576 photjpeg ?

Yes but you use one part of the same image do you not? That is how Watchout and other systems work. all you are seeing is a different section of the same image or clip.

When you use the new panorama functions you are essentially doing this. Your mask for instance would be a single file across 4 screens not 4 separate files.

I have a 4 x Raptor RAID that can give me 4 layers of DV but not 1024 x 768 Photo Jpeg without some dropped frames. As Richard says, you really have to try it. I have an Xserve RAID but I still have to check every combination I come up with.

Cheers

Toby

[samsc]

4 layers of DV playback needs a 4 x Raptor RAID though

please - you need to test with YOUR content - or something like your content - as photojpeg has different performance for each file and different compression settings.
its quite variable. it is very difficult to give general performance guidlines outside dv files - as every file is different.

the performance of dv files is constant because they have a fixed bit rate.

start with something minimal - say a single raptor - no need to do any kindof raid to start with- and see what happens.
tell me what you see. please.

typically - you will not see any performance difference at standard definition - with your files at 768x576 between a single disc -and a raid system.
raid systems are only important when the data rate is the limiting factor - in uncompressed movies.

[samsc]

I find it a bit hard to believe that there's no other solution to my harddrive speed problems then buying the xserve raid ...
How about the Fujitsu MAU3147NP (Ultra 320) and an Atto PCI UL5D pci-e card. Would that be sufficient (theoretically) to drive 4 layers of either DV-PAL or 768x576 photjpeg ?

you dont have to buy an expensive system - you just need to test your files on your system - and see what happens.

photojpeg performance is very different from dv performance.