Datarate question

[dufte]

hi together

I am a new user of this forum an looking forward that you can help me. For my bad english I am sorry.

1.) Datarate of a 4k, 4:4:4, 10bit workflow

I have read in this forum that the datarate is about 300Mbyte/s. But in dependence of the sampling rate, 4k definition and 10bit @24fps i get about 1Gbyte/s if its uncompressed RAW Data. So how can this be, because 300Mbyte/s rate for uncompressed is to small.

2.) do someone know whats the ASA Value of the CMOS Chip of the camera??

thanks a lot
dufte

[Rob Lohman]

((4096 * 2304 * 12) / 8) * 24 = 339.738.624 bytes / second = 324 MB/s

Don't worry about the datarate! When recording you'll want to record to REDCODE RAW, our compressed format, at around 30 MB/s (4K @ 24 - 30 fps).

We record RAW, not RGB. So you don't multiply the data 3 times (your 1 GB/s number). Also we are 12-bit (hence the number 12 in the calculation above), not 10.

[dufte]

thanks a lot Rob...ok now its clear

[jamesedwelland]

I have a data rate question, the answer according to the RED website seesm to be NO but I wanted to check:

Can I shoot Super35 and output using RedCode Raw?

And if so, would it be 10bit log 4:4:4?

cheers

james w

[David Mullen ASC]

What do you mean by "shoot Super-35"?

Also, RAW, by definition, is a bayer-filtered image, and 12-bit in this case -- it would have to be de-Bayered and converted to become the common 10-bit Log 4:4:4.

Also, "4:4:4" is really a video term and would be used if you were converting to 10-bit Log 4:4:4 HD (1920 x 1080). If you were converting to 2K or 4K, it would be RGB, not 4:4:4, although they sound like the same thing.

So the most common formats for film-out work would be:
4K RGB
2K RGB
1920 x 1080 HD 4:4:4

All 10-bit Log probably.

[jamesedwelland]

I was actually just wondering if the REDcode Raw codec can cope with the slightly larger sensor size of super 35 (RED's definition being 24.4 x 13.7mm). RED's website suggets not I think unless I'm being dumb:

http://www.red.com/formatoptions.shtml

As regards your other points, I was looking at the tech specs page:

http://www.red.com/techspecs.shtml

and the REDCODE codec (which I guess is REDCode Raw?) confused me as it seems to suggets that the Redcode codec outputs 2k 4:4:4 10 bit log.

So, can you help me on my learning curve? ie:

1) can you shoot super 35mm sensor area and use redcode raw?
2) what is the output of redcode raw? Is the red website wrong when it suggests 10bit log 4:4:4? I guess you are saying yes..
3) is un-demoasiced the same as non-debayered the same as bayer-filtered?

Probably some basic stuff here but if I dont get this now I'll be more of a fool later.

Cheers

james w

[Rob Lohman]

1) no, not at this point in time at least. S35 is 4.5K in our case

2) if you look closely at the second link you give it mentions the 10-bit (log) and 4:4:4 options for the RGB path, *NOT* the RAW path. As David correctly answered, our RAW is not 10-bit (log) nor 4:4:4. However, we do not drop any samples (like 4:4:4) as well. So all is good (in both RAW & RGB).

3) yes, although I'm not sure if this "correct" terminology

[jamesedwelland]

Thanks. Had I done the maths I may have realised S35 is 4.5K

Thanks too for clearing up differing terminology re. debayered, demoasiced etc

However, can I be really pedantic and ask if this:

REDCODE codec:
Variable Bit Rate, Wavelet
RAW
10 bit 4:2:2 1080p / 1080i / 720p
10 bit log 4:4:4 2K

should possiby actually read as this:

REDCODE codecs:
REDCODE RAW
Variable Bit Rate, Wavelet
RAW
REDCODE RGB:
10 bit 4:2:2 1080p / 1080i / 720p
10 bit log 4:4:4 2K


Cheers

james w

[Brook Willard]

Remember that there are many different definitions of "Super 35mm" area.

Arri's 3-perf 1.85:1 Super 35mm format is 23.5mm x 12.7mm.
RED's "Super 35mm" format is 24.4mm x 13.7mm
RED's "35mm" format is 22.2mm x 12.6mm

So in reality, the 4K "35mm" format is closer to Arri's S35mm format than RED's 4.5K "S35mm" format is.

A 50mm lens on Arri's S35mm format will have a horizontal FOV of 26.449˚
A 50mm lens on RED's "35mm" 4K format will have a horizontal FOV of 25.361˚
A 50mm lens on RED's "S35mm" 4.5K format will have a horizontal FOV of 27.424˚

So the difference between Arri S35mm and RED's 4K "35mm" is only 4.11% with FOV as the unifying factor.

So can you shoot S35mm REDCODE RAW? Not as RED defines it... but you're 95.89% of the way to Arri's definition!

[jamesedwelland]

I wasnt really concerned with the exact size of Super 35, as no camera manufacturer ever seemes to agree with the exact size, let alone the GG markings! I was being pedandtic, because I want to know and not presume, to ensure that I exactly understand what RED can and cannot do. I know now that at present Redcode raw cannot process all the information from Reds version of Super 35 ('4.5K')

To that end I also wanted to know exactly what was meant on the website re. 'redcode codec' as it seams to mean 'redcode codecs'

Lastly, on the pedantic note, as Rob Lohman intimates, should it be decided whether the term should be 'debayerd' or demoasiced' for the sake of clarity?

cheers

james w