Mulitple 4K RED R3D files playback – computer specs needed

[Dave Haynie]

Ok, not a Red user, but I can help on the math. An R3D file runs either 28MB/s or 36MB/s… yeah, that’s not far from the limit of some 7200RPM drives, but you should be just dandy with one layer per drive. More than that, and you’ll potentially get HDD thrashing… I’ve run into this with Cineform files, which are only about half that size (60GB/hr).

You specified that you’re seeing 120Mb/s on each drive… I assume you don’t mean that (eg, 120 megabits per second), but actually mean 120MB/s (120 megabytes per second). An actual 120Mb/s would be limiting.. your files are a minimum of 224Mb/s.

On your setup, I suspect RAM is a limiting factor. Vegas 32-bit can only use 2GB, and that’s not even all that comfortable a chunk for large 2K projects, much less 4K video. Think of it this way… if you’re only working in 8-bit color, you’re going to need about 27MB per frame per layer, plus all the memory used for Vegas, for compositing, etc. At 32-bit color, that’s over 100MB per frame. No matter how you slice it, 4x the memory footprint of regular 1080p HD work.

I’d recommend using 64-bit Vegas and at least 8GB of memory, before you look any further. A Q6600 is also a pretty ancient 4-core machine… I replaced mine with a Q9550 well over a year ago. But as you’ve seen, it’s not the CPU load that’s the issue.

-Dave

[David Timar]

Hi Dave,

Thanks for your reply. I’ll post my question between your reply here:

“Ok, not a Red user, but I can help on the math. An R3D file runs either 28MB/s or 36MB/s… yeah, that’s not far from the limit of some 7200RPM drives, but you should be just dandy with one layer per drive. More than that, and you’ll potentially get HDD thrashing… I’ve run into this with Cineform files, which are only about half that size (60GB/hr).

You specified that you’re seeing 120Mb/s on each drive… I assume you don’t mean that (eg, 120 megabits per second), but actually mean 120MB/s (120 megabytes per second). An actual 120Mb/s would be limiting.. your files are a minimum of 224Mb/s.”

My bad. I’m getting around 100MB/s on my Samsung 1Tb 103UJ drives. So I guess hard drives are not the bottleneck then.

“On your setup, I suspect RAM is a limiting factor. Vegas 32-bit can only use 2GB, and that’s not even all that comfortable a chunk for large 2K projects, much less 4K video. Think of it this way… if you’re only working in 8-bit color, you’re going to need about 27MB per frame per layer, plus all the memory used for Vegas, for compositing, etc. At 32-bit color, that’s over 100MB per frame. No matter how you slice it, 4x the memory footprint of regular 1080p HD work.

I’d recommend using 64-bit Vegas and at least 8GB of memory, before you look any further. A Q6600 is also a pretty ancient 4-core machine… I replaced mine with a Q9550 well over a year ago. But as you’ve seen, it’s not the CPU load that’s the issue.”

Curious… I was under the impression, that if you set the Video RAM to be used by Sony Vegas to 0, then all it’s doing, is reading the videos from the wherever they are, without trying to use the specified RAM for caching. So how come RAM matters then?

You’re saying 100MB per frame. Is that what Sony Vegas needs in memory, in order to actually play back a 4K video? How did you calculated that?

Switching to at least 8GB of RAM would be an easy fix, but I’m worried that it’s not enough to solve this problem.

Dave, do you think it’s possible, that I make a R3D file available for you, you download it, copy it 2 more times so you have 3 separate files, then see if you can play it back properly?

Thanks
David

[Dave Haynie]

The video preview RAM is only for, well, RAM preview. As I understand it, if you don’t select a region and select “Build Dynamic RAM Preview”, this doesn’t get used. Vegas manages the caches and all for normal rendering/compositing on its own.

I would assume, if you’re using Red footage, you’re at least sometimes (color grading, etc) editing in 32-bit mode. That’s 32-bits per color, rather than 8-bits, as I understand it. So that’s 4,096 x 2,304 x 4 x 3 = 113,246,208 bytes per frame. In 8-bit mode, sure, it’s only 28,311,552 bytes per frame. But either way, it’s still 4x more of everything than the same stuff in 2K/HD. And I’ve found 2GB limits kind of on the edge of where HD editing starts to get good. Last year, I upgraded to 64-bit Windows 7, laptop and desktop, specifically to run 64-bit Vegas for HD editing. I do electronics CAD on this same PC, and that’s totally happy in 32-bit, even with 3D preview. Video is by far one of the few remaining Big Problems for home/small office computing.

-Dave

[David Timar]

Hi Dave,

I’d be editing in 8-bit mode, as color grading is not important.

Still, what would you suggest? Who should I contact? Who can give me a definitive answer to the hardware requirements of playing back 3 4K RED videos simultaneously in Sony Vegas (Draft Full or Preview Half mode at least)?

Thanks
David