Codec/ hardware/software for jumbo-frame size video playback on desktop?

Question

Hello all,
I am looking for a codec that I can render to from AE and FCP, and can preview 1/2 or 3/4 scaled and actual scle (partial) on my 30" mac desktop.
ideal size: 3840x2160 (16:9) 25 fps 604 MB/sec CODEC for desktop PB
the AJA whack test on Dulce RX shows (720MB/sec.)easily enough disk throughput to handle 604MB/sec,
but apple uncompressed 10 bit 4:2:2 won't play more than 5sec.
my problem is not editing and rendering of which I will do a variety of methods, but rather
?????what uncompressed codec etc. to render TO????....how to see it,
1/2 or 3/4 scale or actual scale (partial)
on my 30" desktop
so I can check composition...before we finnally have it chopped up for seperate projectors or in the very fancy installation projection system
or to identify the hardware/software bottle necks to playing such a frame size on my desktop.
thanks,
Hilary

Answer 1

Wow, you are definitely on the bleeding edge, Hilary, trying to produce quad-HDTV on a Mac. One thing you might want to try, if you haven't already, is to post your questions at the AVScience forum. I think you will find a more focused audience there.
I don't really have answers for you, but I do have more questions and possibly some things to think about. First question; is the source material really quad-HDTV or is it lower res, like normal HDTV, and the plan is to show it through four, 1080p projectors onto a video wall? The reason I ask is, if the source material is lower res, then it seems pointless to try and encode it as quad-HD. You could just encode as HD (1080p) and then chop it up into four 960 x 540 chunks and project that.
You mention that you have encoded Apple uncompressed 10-bit 4:2:2 but that the file will only play for five seconds. What happens after that? Does it get choppy or does it just altogether stop playing? The answer may hold clues as to what the problem is.
What will the be the final platform for playing this video through the four projectors? Will it be the same G5 PowerMac that you are producing on or is the playback system based on different hardware? That could influence the encoding choice.
It seems the most ideal development system for what you are trying to do would not be on a 30" monitor but instead on four 23" Cinema Displays connected to two graphics boards installed in your G5. Then you could be working at full scale aross all the monitors and you wouldn't have to worry about 1/2 scale or 3/4 scale or partial full scale viewing.
It sounds like you have verified there to be adequate throughput off the disk to play the file at 25 fps but it's hard to imagine that a ~0.6 GBytes per second data stream isn't going to bottleneck somewhere on the G5. That's like 10x the data rate of FW800 if I am reading your post correctly. Maybe you meant 604 Mbps? That's just inside the (theoretical) envelope of FW800, but still a lot of data to be streaming real time without interruption. But where is the pinch point? That is the question. I'm guessing that it is disk related inspite of what the AJA whack test says. Are you using a raid by any chance? That should improve the AJA score and make for more headroom, especially if run off a SATA card.
Personally, I rarely use anything more powerful than Apple's Activity Monitor as a system monitoring tool. But I doubt that it has enough diagnostic power for this application. If you are running Leopard, DTrace might be helpful, but I have no experience with it personally. Just trying to find the bottleneck could turn into a whole project of its own. Again I refer you to the AVScience forum as a possible shortcut to the answers you seek. Good luck with your project.