Welcome to our community

Be a part of something great, join today!

Log in
  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Hard drive for 4K workflow?

M

Mike 50

Member
Joined
Jan 18, 2007
Messages
6
Reaction score
0
Points
0
Greetings everybody. I can imagine how excited everyone must be about the Red. It's sort-of like a milestone in history.

Anyway, I have a quick question....

I realize to capture uncompressed RAW you need a hard drive that can write at 323MB/s. There is REDCODE, only 27MB/s. But, when you eventually decompress it to DPIX/TIFF/MPEG, do all the post work - then:

Do you still need a hard drive that can read at 323MB/s to let's say laser-print to 35mm?

Can you get away with a SATA drive instead of a Fiber Chanel/SCSI which cost 10x more?

Also, if anyone knows; What type of cable does RED output with (in uncompressed RAW)?

Thank you.
 
EDIT: THE FOLLOWING NUMBERS ARE INCORRECT, SEE THE NEXT 2 POSTS

Our uncompressed RAW port is an optical port. It's not something you can easily pipe into something else to record. Hence our product RED-RAID.

You do not *need* 323 MB/s or faster "drive", unless you want to do things with that stream in real-time.

If you have the money to laser-print I would say a fast SAN/NAS system should not be much of a problem :)

If you want/need a cheaper option I would think about getting SAS (Serial Attached SCSI) or SATA drives together with a PCI express RAID board that lets you hook up say 24 drives.

Shooting 4096 x 2304 at 24 fps in 16-bit (padding 12-bit) gives 432 MB/s
Shooting 4520 x 2540 at 24 fps in 16-bit (padding 12-bit) gives 526 MB/s

DPX is a format that can pack these bits together without wasting so much space. Assuming you output in some 10-bit space you would need for DPX:

4096 x 2304 at 24 fps in 10-bit DPX: 270 MB/s
4520 x 2540 at 24 fps in 10-bit DPX: 329 MB/s

The overhead for the DPX file format is *NOT* included in these calculations.

Again, if this is solely for laser-printing you might not need this speed. I looked up the ARRILASER: http://www.arri.com/prod/digital/arrilaser/index.php

< 2.9 seconds per 4K frame (1:1.85)
< 3.8 seconds per 4K frame (full ap)

So let's say you crop your resolutions to 1.85:

4096 x 2214 for 10-bit DPX is around 11 MB per frame
4520 x 2444 for 10-bit DPX is around 14 MB per frame

They say it's under 2.9 seconds. It's a weird number to give so I'm assuming they mean it'll be around 2.8 seconds per frame. Then you need a data rate of 11 / 2.8 = 4 MB/sec or 14 / 2.8 = 5 MB/sec, excluding over head.

Not really spectacular :) Obviously faster lasers printers may exist (I'm by no means an expert on laser printing). 2K printing is also faster, but still nowhere near real-time on that ARRILASER, for example.
 
Rob Lohman said:
...
4096 x 2304 at 24 fps in 10-bit DPX: 270 MB/s...
Click to expand...

Hi Rob...

Are you talking about RAW or DPX? I may be misunderstanding something (entirely possible...,) but take a look.

4096 * 2304 = 9,437,184 (number of pixels in the file)

9,437,184 * 32 = 301,989,888 (number of bits in the file - each pixel = 32 bits in a 10-bit DPX file)

301,989,888 / 8 = 37,748,736 (number of bytes in the file)

37,748,736 / 1,048,576 = 36 (number of megabytes in the file)

So each 4096*2304 10-bit DPX = 36 MB/frame.

36 * 24 = 864

So realtime playback of that 10-bit DPX sequence would need 864 MB/s.

Cheers,

Lucas
-----
ASSIMILATE, Inc.
Los Angeles
 
D'oh! Must've still been sleeping, thanks Lucas. All those numbers get confusing.

Okay, so here are the proper numbers then (hopefully):

4096 * 2304 at 24 fps in 10-bit RGB DPX = 864 MB/s
4520 * 2540 at 24 fps in 10-bit RGB DPX = 1051 MB/s

In the 1.85 aspect ratio:

4096 * 2214 as a 10-bit RGB DPX frame = 35 MB
4520 * 2444 as a 10-bit RGB DPX frame = 42 MB

At 2.8 seconds per frame for laser printing that's 12.5 MB/s & 15 MB/s
 
Okay, so basically you don't need a faster drive to transfer from RED RAID to your own RAID SAN? Even if your SAN is SATA?
 
Not sure what you mean with "a faster drive". The slowest part in the link will determine speed you're getting.
 
You know how when you capture a DV tape from a camcorder to your computer over USB - it's in real time?

Is it like that with a RED RAID? Because if it's real time capture you would in theory need a RAID that could write at 323MB/s for RAW.
 
Mike 50 said:
Our uncompressed RAW port is an optical port. It's not something you can easily pipe into something else to record. Hence our product RED-RAID.

You do not *need* 323 MB/s or faster "drive", unless you want to do things with that stream in real-time.
Click to expand...

Actually I guess this answers my question.
 
You would definitely want a SAN solution, but if you want to go laser print to film, then you just deliver a big firewire drive to the post house you will be using.
 
Reading tends to be faster than writing. So you can expect to read faster than real-time off the RED-RAID. How much remains to be seen. Obviously the system is designed for full 4.5K @ 60 fps. If you record 2K or lower frame rates you're storing smaller files which will also transfer faster.

It's a bit early to start talking about RED-RAID details. We're focussed on the camera, monitoring, RED-DRIVE, REDFLASH etc. first.
 
does it need to be smaller and faster than this 500kb drive from 1975?

http://www.boingboing.net/2005/11/11/500kb_of_hard_drive_.html

251_1169504199.jpg
 
Ah Agwah, the first transportable ipod. What was the tag line? Oh yeah---"One Song, One Drive.... Be One." ...memories
 
You must log in or register to reply here.
Back
Top