Topics

Linear export from FCPX

Colin Elves
 

Hello,

Does anyone here have much knowledge/experience with FCPX? I’ve been playing around with ProRes Raw workflows and I’m trying to work out how to get linear light exports out of it.

According to the Apple ProRes Raw white paper “Decoding ProRes RAW directly results in HDR linear values rather than log.” And if you select ‘none’ for both the ‘Raw to log’ and ‘Camera LUT’ Settings you can “color correct ProRes RAW video as HDR video, regardless of the library color-processing setting... No tone mapping is applied to the source, and the full dynamic range is available in the working space, even in libraries set to Standard color processing. Although highlights may initially appear blown out, you can correct this using color correction tools, such as Color Wheels and Color Curves.”

However, when I’ve done this, exported the file (as both ProRes and EXR sequences) the resulting file appears to have a very harsh gamma baked in and does not appear to behave like a linear file at all.

Does anyone who knows FCPX a bit more habe any idea how to properly export this ‘HDR Linear’ data?

Thanks!

Colin Elves,
DP, Berlin/London.

 

Hey Colin.

Any chance you can put a short 10 sec clip somewhere like dropbox?

I would really like to get my head around Prores RAW workflow.

Michael Sanders
London Based DP.

+ 44 (0) 7976 269818




On 16 Jun 2018, at 13:07, Colin Elves <colin@...> wrote:

Hello,

Does anyone here have much knowledge/experience with FCPX? I’ve been playing around with ProRes Raw workflows and I’m trying to work out how to get linear light exports out of it.

According to the Apple ProRes Raw white paper “Decoding ProRes RAW directly results in HDR linear values rather than log.” And if you select ‘none’ for both the ‘Raw to log’ and ‘Camera LUT’ Settings you can “color correct ProRes RAW video as HDR video, regardless of the library color-processing setting... No tone mapping is applied to the source, and the full dynamic range is available in the working space, even in libraries set to Standard color processing. Although highlights may initially appear blown out, you can correct this using color correction tools, such as Color Wheels and Color Curves.”

However, when I’ve done this, exported the file (as both ProRes and EXR sequences) the resulting file appears to have a very harsh gamma baked in and does not appear to behave like a linear file at all.

Does anyone who knows FCPX a bit more habe any idea how to properly export this ‘HDR Linear’ data?

Thanks!

Colin Elves,
DP, Berlin/London.

Colin Elves
 

Here you go Michael: https://www.dropbox.com/sh/iyryanhwk3qc0zm/AAAoCJQbr8CkCXK-y98LhdaSa?dl=0

Also, here’s a crappy video guide I put together on how to convert to Vanilla ProRes Log for editing/grading in other software (after a few people asked for a guide): https://m.youtube.com/watch?v=JbOGHHaIRmc&feature=youtu.be

But I would like to work out how I can get a linear file out!

Colin Elves
DP/EU


On 16 Jun 2018, at 14:49, Michael Sanders <glowstars@...> wrote:

Hey Colin.

Any chance you can put a short 10 sec clip somewhere like dropbox?

I would really like to get my head around Prores RAW workflow.

Michael Sanders
London Based DP.

+ 44 (0) 7976 269818

 

Thanks Colin - really appreciate that.


Michael Sanders
London Based DP.

+ 44 (0) 7976 269818




On 16 Jun 2018, at 14:18, Colin Elves <colin@...> wrote:

Here you go Michael: https://www.dropbox.com/sh/iyryanhwk3qc0zm/AAAoCJQbr8CkCXK-y98LhdaSa?dl=0

Also, here’s a crappy video guide I put together on how to convert to Vanilla ProRes Log for editing/grading in other software (after a few people asked for a guide): https://m.youtube.com/watch?v=JbOGHHaIRmc&feature=youtu.be

But I would like to work out how I can get a linear file out!

Colin Elves
DP/EU


On 16 Jun 2018, at 14:49, Michael Sanders <glowstars@...> wrote:

Hey Colin.

Any chance you can put a short 10 sec clip somewhere like dropbox?

I would really like to get my head around Prores RAW workflow.

Michael Sanders
London Based DP.

+ 44 (0) 7976 269818

Adam Wilt
 

Does anyone who knows FCPX a bit more have any idea how to properly export this ‘HDR Linear’ data?

I don’t think you can: there are options to set the project’s “gamma” to SDR Rec.709, HDR PQ, or HDR HLG, and master file exports follow that “gamma” (OpenEXR image sequence exports are inexplicably forced to Rec.709, even for HDR projects). There’s no way that I know of to export a linear-data file untouched by SDR or HDR “gamma”.

True, the internal processing is treating the file as linear data, unbesmirched with nasty tone mapping, but that’s just the internal processing pathway. The final output is tone-mapped in any “gamma” you want — as long as it’s Rec.709, PQ, or HLG. Linear simply isn’t one of the options.

Here’s the HDR workflow white paper: https://images.apple.com/final-cut-pro/docs/Working_with_Wide_Color_Gamut_and_High_Dynamic_Range_in_Final_Cut_Pro_X.pdf

Your best bet may be to export an FCP XML file, import it into Resolve, and perform your data exports there — assuming ProResRAW can be decoded on Resolve, which I don’t think is possible yet (I could be wrong, but I don’t have any ProRes Raw files to test with).

If you’re feeling really brave, set up the project as HLG and apply a global HLG-to-linear LUT (inverse HLG mapping) to “de-gamma” everything — sounds great in theory but I doubt it’d work quite so transparently in practice!  You could try the same trick with a PQ or 709 project, too; just make sure you grade everything to stay under the project’s clipping level. In all cases, unless you have a perfect inverse LUT, expect some errors in the resulting linearized tonal scale.

Aside from those sorts of things, you may be stuck: until Apple opens up the licensing on the ProRes RAW codec, your ProRes Raw media are likely trapped in an FCPX ghetto.

Cheers,
Adam Wilt
technical services: consulting / coding / camerawork
Vancouver WA USA (no, not that Vancouver, the other one)

Nick Shaw
 

On 17 Jun 2018, at 07:26, Adam Wilt <adam@...> wrote:

The final output is tone-mapped in any “gamma” you want — as long as it’s Rec.709, PQ, or HLG. Linear simply isn’t one of the options.
I'm not an FCP-X expert, but can you export in a camera log format? For example, an uncompressed 16-bit V-Log/V-Gamut file will contain just as much information as a linear file, and can be accurately linearised in your compositing app.

A log file will (should) not include any tone mapping.

Nick Shaw
Workflow Consultant
Antler Post
UK

Colin Elves
 

Adam: Thanks. You’ve basically confirmed what I already suspected it is currently impossible to export the linear data.

Nick: The Raw to Log menu gives you the options of clog2/Cinema Gamut, V-log/V-gamut, Slog3/SGamut3 and Slog3/SGamut3.cine - and as best as I can tell these files do match the log output of the camera - and match the ACES interpretation of the log from CDNGs, so I guess that will have to do. Just seems like an opportunity for error to have to convert the data twice.

Colin Elves
Director of Photography
Berlin & UK



On 17 Jun 2018, at 15:46, Nick Shaw <nick@...> wrote:

On 17 Jun 2018, at 07:26, Adam Wilt <adam@...> wrote:

The final output is tone-mapped in any “gamma” you want — as long as it’s Rec.709, PQ, or HLG. Linear simply isn’t one of the options.
I'm not an FCP-X expert, but can you export in a camera log format? For example, an uncompressed 16-bit V-Log/V-Gamut file will contain just as much information as a linear file, and can be accurately linearised in your compositing app.

A log file will (should) not include any tone mapping.

Nick Shaw