Delivering for Broadcast after creating for Web

Hey all!

We are an agency creating content for social media primarily but occasionally an asset gets the ‘glory’ of being broadcasted on television :slight_smile: (social media is a lot bigger but hey, it’s larger screens hehe)

We work completely in the Adobe ecosystem where editing and finishing happens in Premiere Pro.
All our monitors are sRGB limited and profiled or hardware calibrated to sRGB. Because web doesn’t convert rec.709 gamma we basically ignore management so what we see is what we get.
In the case of a broadcast version this would make everything darker because our decisions were sRGB based.

The question here is:
Is using OCIO to go from Output sRGB to Output rec.709 a valid way of countering this? It would make it quite easy for us to prepare the broadcast version this way. Just slap it on top of the graded file and place all graphics above it.

Love to hear if this works or if there are other / better ways.

That seems reasonable to me. Basically what you want to do is undo the sRGB EOTF and apply the Rec. 709 EOTF. I’m not a complete pro with OCIO but I believe converting one output to the other should accomplish your goal. (Hopefully someone will correct me if I’m wrong :slightly_smiling_face:)

Thanks for your reply Scott!
I was thinking maybe there can be some tricky situations dealing with inverting RRT and back again.
Would a single lut file be cleaner in this regard or same result?

I am not entirely sure how intelligent OCIO 1.0 is with optimisation. Because it is LUT based, this approach might well end up going through an entire inverse RRT+ sRGB ODT transform, followed by a forward Rec.709 one, when all that is really needed is a simple 1D LUT. How significant any loss due to this might be I cannot really say. It may well not be noticeable.

Actually, I just did a quick test in Nuke, and you can definitely see a difference in the shadows on the waveform between the actual Rec.709 Output Transform and an sRGB Output Transform followed by an OCIO conversion from Output - sRGB to Output - Rec.709. Doing the conversion as a pure 1D transform gives a much better result.

EDIT: Using an OCIO Colourspace conversion with

  • in = Utility - Curve - sRGB
  • out = Utility - Curve - Rec.1886

does it the 1D way, and gives a better result.

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Thanks for chiming in @nick . When I wrote my response this is what I was thinking about but it didn’t occur to me that OCIO v1 converting between the Output options would run an inverse/forward combination.

The 1D approach is simpler, cleaner, and exactly what I was intending in the first place.

Thanks @nick ! That’s exactly what I was wondering when I started this question.
I didn’t realize this could also be achieved with the config. I will add them to our stripped down config. Very clean solution thanks a lot :slight_smile:

I asked BorisFX a while ago about OCIO v2 implementation mostly for GPU support and they said they were going to look into it so we’ll see that hopefully in the near future.