REC709/Video

[Irri]

If I export from RedCine to REC709, is it correct to import into applications as video (64-940) or as (0-1023)?

 

[Irri]

57 views and no answer? I can't believe that many people don't know the answer to this.

 

[Dj Joofa]

If I export from RedCine to REC709, is it correct to import into applications as video (64-940) or as (0-1023)?

Rec 601 space (a confused space as it mixed up several quantities -- NTSC and digital -- to get "incorrect" formulae just to be historically accurate) mandated luma to be in 16-235 range (in 8 bit numbers); if a "straight stretch" is done then in 10 bit numbers they become (16-235)*4 = (64-940).

However, I don't fully remember if Rec 709 mandated the same 16-235. Probably not. Therefore, 0-1023 should make sense. However, it all depends on how Red has done it. Different manufacturer's often "mix" up specs just to get visually pleasing results.

 

[Dj Joofa]

Okay, here is a section from ITU-R BT.709-5:

10-bit coding

Quantization levels
– Black level
R, G, B, Y : 64
– Achromatic
CB, CR : 512
– Nominal peak
– R, G, B, Y : 940
– CB, CR : 64 - 960

Quantization level assignment 10-bit coding
– Video data : 4 through 1019
– Timing reference : 0-3 and 1020-1023

 

[arapro]

Video is the correct ansewer I belive ! just be sure that the format and gamma are set to REC709

 

[Irri]

Thanks guys. I guess we need to know how RED intended it to be used.

By the way arapro, you use REC709 as format instead of Camera RBG? I find the colours go very strange when I do that.

 

[arapro]

Irri,
Yes, we always use Format REC709 and Gamma REC 709 - and this turns out to be the best setting when going DPX files into Baselight.
What do you mean by strange ? are you doing a one light ?

 

[Lucas Wilson]

Irri,
Yes, we always use Format REC709 and Gamma REC 709 - and this turns out to be the best setting when going DPX files into Baselight.
What do you mean by strange ? are you doing a one light ?

Hi arapro,

That may be the best settings for you... and that's cool.

But several Baselight suites in LA that I know use either PDLog685 or RedLog in order to get R3D footage into log space for grading in Baselight. By outputting Rec709, you are staying linear. Which is fine too if done right!

But there are two very different ways of treating the footage.

Best,

Lucas
------
ASSIMILATE, inc.
LA, CA, USA

 

[Irri]

People used to say transfer Camera RGB/REC709. The only reason I ever saw REC709/REC709 was because the proxies got encoded this way. I often look at proxy offlines an think the colours are too saturated. I export Camera RGB/REC709 to DPX. That's not to say I am right.

 

[Ed van der Kruijssen]

Exporting to REC709 is a pity because you're losing a lot of information in the blacks and highlights. Why don't you export to RedLog or PDLog because that way you keep all the headroom of your shots for making a proper colorgrading.

Regarding limited bandwidth (64-940) or full bandwidth (0-1023) I advise you to export to full bandwidth and depending on your delivirables do a grade,conform whether in full bandwidth if its for output to Film,digital cinema and playback on computer (internet) and do a limited bandwidth (64-940) grade,conform if it's for playback on Consumer Screens like LCD/Plasma. These consumer screens are all limited bandwidth (64-940)

 

[Deanan]

By outputting Rec709, you are staying linear.

ACK! REC709 is not linear.
REC709 is gamma encoded linear (with a straight segment at the bottom).

 

[Lucas Wilson]

ACK! REC709 is not linear.
REC709 is gamma encoded linear (with a straight segment at the bottom).

Sorry -got sloppy. You're right. : )

Lucas

 

[Graeme Nattress]

Deanan joins the gamma police force!

Graeme

 

[Irri]

Two RED people post in the thread and are both too busy with gamma corrected linear to answer the question :w00t:

 

[arapro]

@ Lucas

This are the best settings we have tested for going to Video !
For Film and others, We are now testing with the two settings you mentioned !
And also, when you say PDLog685 or RedLog, is this in the Format or the Gamma ?
Cheers,
Arapro