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FCP Color and Gamma Handling on 4:4:4 RGB Media
Hi Everybody.
We shot RAW footage (RED). Converted (First Light CC) to 10 Bit DPX. Converted to AJA 10 Bit 4:4:4 RGB Codec. Went to Color to grade (10 Bit Mode). Exported in the same AJA Codec, imported to FCP (6.0.3), the timeline matches the codec settings. Clips playback fine (look great), the image is identical to that in Color. As soon as I render anything with those clips (crop, filter, size, etc. doesn’t matter what) I see a dramatic shift in what I perceive to be a darker Gamma Level. I see this both in the Viewer, as well as the Kona3 Dual Link Output.
The render settings of the time line are RGB.
Can someone explain what might be happening here? How does FCP really handle RGB footage? FCP is YUV native, is that correct?
I could just readjust the gamma an be (visually) happy. But this defeats the purpose, doesn’t it? Constantly jerking a picture back an forth.
Any thought on this would be appreciated,
Tobias
In Touch Media Entertainment
Munich, Germany -
15 Replies
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Hi Tobias,
Is the setting of your sequence codec Full range?[Tobias Heilmann] “FCP is YUV native, is that correct? “
No really. FC is a Video Editing application and video is YUV.
But FC works perfect in RGB. In fact until three or four years ago all the FC effects and transitions rendered in RGB.
When you change from one color system to the other is normal that happens some shifts in colors and gamma,but when you fallow all the process in one or the other this shouldn’t happens.
rafael -
We used the full range, as we wanted to keep the field open until the time we needed to narrow it down.
Of course I am not sure whether Color exports the exact same way, as I ony choose the codec.Does FCP not support this?
In Touch Media Entertainment
Munich, Germany -
In Color you have no option so I guess is Full range. In FC you can choose, this is why I suggested to check how was set.
Rafael -
[Tobias Heilmann] “Any thought on this would be appreciated, “
Tobias
the only true way to handle RGB files in FCP is to NOT make them into video, to maintain the data correctly you have to
make sure that you set FCP to render in RGB, not adjust Gamma correction, and not use filters or transitions that are not 10bit.
and turn off the RT engine – you will need to work in SAFE RT.
This is as much a QT issue as it is an FCP issue, QT is Natively 8bit too.
gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Inside look at the IoHD -
Tobias,
I am not a red user, but I did come across these two white papers:
and this one:
These papers discuss how FCP handles 10-bit material and may point you in the right direction. The basic gist of the second paper is that very few FCP effects are 10-bit enabled and FCP never tells you when it takes 10-bit material down to 8-bit on effect that are not capable of 10-bit rendering.
Hope this helps.
Jeffrey Di Lullo
bbc&s video communications -
Thank you.
I have not read those two papers yet… but it goes straight to my question: How do I know what FCP is doing to my footage?
We even tried just re-exporting the AJA 10 Bit RGB 4:4:4 clip from the timeline without doing anything to it at all. We then compared the exported clip to the clip that Color generated. The FCP clip is darker.
We compared the two clips by viewing them via AJA TV, our Kona3 via Dual Link Out.
My head is full question marks…
In Touch Media Entertainment
Munich, Germany -
Thank you.
I have not read those two papers yet… but it goes straight to my question: How do I know what FCP is doing to my footage?
We even tried just re-exporting the AJA 10 Bit RGB 4:4:4 clip from the timeline without doing anything to it at all. We then compared the exported clip to the clip that Color generated. The FCP clip is darker.
We compared the two clips by viewing them via AJA TV, our Kona3 via Dual Link Out.
My head is full question marks…
In Touch Media Entertainment
Munich, Germany -
…ok I just read those links. Thank you! Very interesting.
Can’t say that the question marks have vanished. These papers explain a problem, which is yet of a totally different scope.
From reading those papers I still can not discover, why FCP would change the look of my footage just by placing it in a timeline (identical to the footage) and then exproting it from there…. Hmmm.
In Touch Media Entertainment
Munich, Germany -
Well, is clear. The only thing you can do with 10RGB footagein FC without spoil it, is to cut and export without re-compression.
In the moment that you render, your 10b RGB become a 8b RGB. So instead of having 1024x1024x1024 colors, you have 254x254x254.
The only better solution than the one pointed in the articles, is to use Sheer !0b YCbCr 444.
You would keep the most of the color information from the 10b RGB 444.
rafael -
My understanding is that imported RGB media is affected by the gamma setting in User Preferences > Editing > Imported Still/RGB Video Gamma.
If you haven’t already, you might want to change it from the default setting of “Source” and run some tests again.
Martin
Digital Heaven, London UK
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