4K RAW data rates

[Stuart English]

There has been some speculation on various boards as to the accuracy of our stated data rates for 4K RAW uncompressed data - i.e the data rate PRIOR to compression... The math is as follows :

4K at 24fps RAW - 4096 x 2304 x 24 x 12 / 8 / 1024 / 1024 = 324MB/s ..

After REDCODE RAW compression this is reduced to about 28MB/s (224Mb/s)

From the high speed data port, our maximum uncompressed data rate is -

4.5K at 60fps RAW - 4520 x 2540 x 60 x 12 / 8 / 1024 / 1024 = 986MB/s (7.888 Gb/s)

[tucamone]

is it possible to transfer data at almost 1GB a sec without fry the sensor.? Is there such hard disc capable of that?

[Emery Wells]

When it gets REALLY fun is when you take that 60fps RAW data @ 986MB/sec and process it to a linear or logarithmic image sequence (DPX, Tiff, whatever.) Im not sure what the data rate would balloon to but I suspect it would be over or close to 2GB/sec (thats Giga Bytes!.)

So that wold mean youd need 1.2TB of storage to hold 10 minutes of 60p 4k uncompressed footage, hooray!

[Emery Wells]

is it possible to transfer data at almost 1GB a sec without fry the sensor.? Is there such hard disc capable of that?

There is no single drive that can handle that data rate but there are many RAIDS which are plenty capable, course they cost a pretty penny.

Anyone interested in a 4k uncompressed DI workflow should be looking into getting the new Quad 4GB Fibre Channel HUGE Media Vaults 4440 capable of 1.5GB/sec. They'll cost you a few REDS.

[Jarred Land]

a 36 drive array should be able to handle the data rate comfortably.

a 12 drive array can handle 24p, and with RED CODE, all you need is a single 3.5" or dual 2.5" drive.

[tucamone]

The REDCODE seams the best way to go!

[visceralpsyche]

If I read this forum correctly, the camera will have between 32-64GB of onboard RAM to supplement the main storage. This would absolutely make sense - if you need a speed ramped shot up to 60/120fps, then the main storage magazine may not be able to do it in real time even with RedCode.

BUT.... if you can do a take with the footage going into RAM until the take is over (it would have a time limit obviously based on amount of RAM), then automatically transfer it to the main storage while you reset for take 2 etc, you'd have the problem licked. Seems like a brilliant answer to the problem of high speed footage acquisition at 4K. I hope I'm close to the mark...

[janghos]

There has been some speculation on various boards as to the accuracy of our stated data rates for 4K RAW uncompressed data - i.e the data rate PRIOR to compression... The math is as follows :

4K at 24fps RAW - 4096 x 2304 x 24 x 12 / 8 / 1024 / 1024 = 324MB/s ..

(7.888 Gb/s)

I've tried to get this calculated in my head, but I couldn't understand all the elements.

4096(the amount of the horizontal pixels) x 2304(the amount of the vertical pixels) x 24(the amount of the frames) x 12(the amount of bits per channel) / 8 (?) / 1024(?) / 1024(?) = 324MB/s

Could anyone help me replace those question marks?
Thanks in advance.

Nook

[khmuse]

I've tried to get this calculated in my head, but I couldn't understand all the elements.

4096(the amount of the horizontal pixels) x 2304(the amount of the vertical pixels) x 24(the amount of the frames) x 12(the amount of bits per channel) / 8 (?) / 1024(?) / 1024(?) = 324MB/s

Could anyone help me replace those question marks?
Thanks in advance.

Nook

The last bit of the math, specifically, the /8 /1024 /1024 is rather simple.

The /8 is conversion from bits to Bytes.

The /1024 is the decimal equivalent of Kilo 2^10 (base 2),

/1024 /1024 is the reciprocal of Kilo Kilo or Mega.

Therefore /8 / 1024 /1024 is the conversion from bits per second (b/s) to MegaBytes per second (MB/s).

[janghos]

Thanks khmuse,
I didn't take the conversion into my consideration, because I assumed that part was done after the math. That was my mistake. Now it all makes sense after your kind help. Thanks a ton.

EDIT: I've noticed a mistake that I made to describe the number 12. It should be bits per pixel, not bits per channel. It would be amazing to have a sensor that records 12 bits per channel, though.

Nook