Shooting HLG - First Experience - Part 2 - HDR

[Laval 21]

Inspired by discussion triggered by my PREVIOUS POST on this topic, and after watching an interview with Alister Chapman, I experimented with HLG footage a bit more  (without a special HDR Monitor).  This time, rather than converting HLG clips to Rec.709 clips, I created a new video in true HLG format, to see how it would work for both HDR and SDR TVs.

 I actually ended up creating two versions of the same video.  Both versions were created with the same Video Codec:

•  ‘HDR TV’ version – in this version I wanted to see what would be the quality of the video without any color grading (okay, almost no color grading)
• ‘SDR TV’ version – in this version I did some minimal color grading to get an image quality on an SDR screen similar to the one an HDR screen (in my subjective opinion).  

I selected several video clips that I shot in HLG (BT2020 color space) at different depths (from 5 m to 35 m) and did the following (mostly following Apple’s recommendations):

1.    Created a library in FCPX and set it to  Wide Gamut HDR

2.    Imported all clips to this library

3.    Slightly adjusted Midtones by lowering brightness to -0.1 (this what I understand Alister Chapman has recommended)

4.    Slightly adjusted Hue vs Hue of Hue/Saturation Curve of a few clips to change water color from greenish to blueish.

5.    Slightly increased sharpness (3.78)

6.     Applied HDR Tool (PQ Output Tone Map)

7.    Shared the project as a Master File, using Video Codec: Apple ProRes 422 and Wide Gamut HDR - Rec. 2020 HLG color space

8.    Uploaded the Master file to YouTube

As you can see from the above steps, I basically did not do any color grading, and all above steps took me only about 5 to 10 min, as I was using adjustment layers, to which I applied most adjustments, rather than to individual clips.  

Here is the LINK to the 'HDR TV' version of the video. 

When I watched this video on the my HDR TV (Samsung Q80R, 2019) I was quite impressed with its quality.  

Then, I watched the same video on my old plasma TV and a 2-year old HDR TV, on iMac, on MacBook Pro (2018), on iPhone X, and on my new Dell laptop (2020). I noticed that colors on these screens got 'washed out' a bit, compared to colors on my HDR TV.   So, I decided to create another version of this video (‘SDR TV’ version), in which, in addition to the above steps 1 to 8, I  made the following adjustments to increase contrast and brightness:

1.    Increased brightness of Highlights up to +0.21

2.    Decreased brightness of Shadows down to -0.22 for some clips

3.    Increased saturation of Midtones slightly

As a result, I got a video with quality  quite comparable to the ‘HDR TV’ version (in my humble opinion).  As such, it appears that for people who do not watch YouTube videos on an HDR TVs  the second version ('SDR TV') would work better. 

Here is the LINK to the 'SDR TV' version of the  video.

Most probably, quality of this second video could be improved further by making some additional adjustments, but I already see that shooting in HLG underwater could produce very good quality videos (at least to my taste) without much grading and without a special HDR monitor.

I should note, however, that I am not sure how good could be quality of underwater footage shot in HLG picture profile using other cameras.  With SONY cameras like the one I have  (Sony FDR-AX700 / HXR-NX80 / PXW-Z90), it is very easy to set manual white balance underwater with just one click, and I did it for every single shot.  Sometimes, however, when there is not much ‘white’ color in a scene to be used by the camera for reference, you have to experiment a bit, and this is where the mastery is.  I am not there yet, and I need to practice more to improve this skill.

Also, I would like to mention that I am not an expert in HLG, and if anyone is interested in learning more about advantages of HLG I would refer to experts like Alister Chapman.  

If you would like to learn more about using HLG in underwater videography, I would refer you to J. M. Núñez’s WEBSITE.  Juan has tonnes of experience in shooting HLG underwater, and his website is full of very useful and practical information and tips.

Please share your opinion about picture quality of the two versions of my video on HDR and SDR screens when you have time.

Thank you all.  Stay home and stay healthy.  

Val

Edited April 10, 2020 by Laval

[Interceptor121 707]

As explained in my tutorial as you cannot see on the HDR screen what is coming out lacking a monitor you need to use the PQ but apply some small improvements than go back to HLG deleting the HDR tools adjustments

The difference you see is because is graded differently not because of HDR / SDR conversion

On my HLG set it shows that underwater footage of the nature captured in your clip has really little dynamic range and does not benefit at all from HDR

Also consider that some translation on computers that use sRGB naturally reduces contrast this depends on the implementation of gamma curve in the device not on your clip

I still think the mix of situation and camera you have does not warrant HDR and you should shoot directly SDR maybe see if you have a log option to record in case you want some headroom

[Lionfi2s 74]

Hi Laval,

I have seen the sdr version of the footage and I think you are pushing the files too much and they just "collapse". You are trying to bring out colors that are not captured the way you want them or not captured at all. The result is ugly chroma noise (lots of it in the blues), loss of texture in reds etc.  My 2 cents forget HLG and log with 8 bit files and a small sensor camera. Try simpler things and stop custom white balancing if you are deeper than 6 meters (maybe 9 in very clear blue waters), Go close and WB on your lights if not using lights just accept that the footage will be blue or green. 

I will later try to watch the HDR on my tv as well

 

[Laval 21]

12 hours ago, Interceptor121 said:

As explained in my tutorial as you cannot see on the HDR screen what is coming out lacking a monitor you need to use the PQ but apply some small improvements than go back to HLG deleting the HDR tools adjustments

The difference you see is because is graded differently not because of HDR / SDR conversion

On my HLG set it shows that underwater footage of the nature captured in your clip has really little dynamic range and does not benefit at all from HDR

Also consider that some translation on computers that use sRGB naturally reduces contrast this depends on the implementation of gamma curve in the device not on your clip

I still think the mix of situation and camera you have does not warrant HDR and you should shoot directly SDR maybe see if you have a log option to record in case you want some headroom

Thank you for watching my videos and your valuable feedback.   I will try your recommendation "use the PQ but apply some small improvements than go back to HLG deleting the HDR tools adjustments". 

[Laval 21]

10 hours ago, Lionfi2s said:

Hi Laval,

I have seen the sdr version of the footage and I think you are pushing the files too much and they just "collapse". You are trying to bring out colors that are not captured the way you want them or not captured at all. The result is ugly chroma noise (lots of it in the blues), loss of texture in reds etc.  My 2 cents forget HLG and log with 8 bit files and a small sensor camera. Try simpler things and stop custom white balancing if you are deeper than 6 meters (maybe 9 in very clear blue waters), Go close and WB on your lights if not using lights just accept that the footage will be blue or green. 

I will later try to watch the HDR on my tv as well

 

Thank you, Lionfi2s.  I appreciate your feedback and recommendations. I will definitely try them.

[Lionfi2s 74]

Not to open another HLG thread, I have found the time and worked on some HLG files that were sitting on my hard drive since 2018.

There are nothing special in terms of content or editing but I just wanted to see how they behave and how much I can push them. 

These were graded and edited on REC 2100 HLG color space and gamut on the free version of Davinci Resolve using only the scopes as reference as I dont have an HDR monitor. No secret sauce on exporting etc, just followed youtube recommendations for HDR content.

I intentionally pushed the files way more that I normally do to have an idea of how much they can be abused and to my surprise and contrary to what I read they handled it well. If this is was a commercial shoot I would have pushed way less the footage to make it more compatible for SDR devices.

If you are watching on an SDR monitor you will notice the abuse more but it is only a matter of the monitor color space, watch it in an HDR tv and you ll see the difference. 

For sure there is more room to play with as HDR and its workflow still holds secrets and requires some extra equipment but I think if you are a bit careful when shooting the footage HLG is a viable and quick solution to have HDR and acceptable SDR content.

PS not LUTS have been used or abused during the making of this clip

 

 

 

[thani 86]

Thank you for sharing. it is a very good test and very encouraging result. Did you shoot in HLG profile or Standard Profile as you wrote in the clip? Why not shoot 400mbps instead of 150?

Edited May 26, 2020 by thani

[Lionfi2s 74]

1 hour ago, thani said:

Thank you for sharing. it is a very good test and very encouraging result. Did you shoot in HLG profile or Standard Profile as you wrote in the clip? Why not shoot 400mbps instead of 150?

It is indeed encouraging for the results and ease of use. With more sensible grading the results will be even better. I shot HLG by standard I mean no modifications to the HLG profile. I was filming some more important footage that I didn't want to experiment with and my v90 card was full so at the end of some dives I played with HLG.

[Laval 21]

On 8/22/2019 at 1:08 AM, AlMitch said:

See answers above. 

 

On 5/26/2020 at 10:32 AM, Lionfi2s said:

If you are watching on an SDR monitor you will notice the abuse more but it is only a matter of the monitor color space, watch it in an HDR tv and you ll see the difference. 

I watched your video on different monitors (SDR and HDR), and I like the quality.  I enjoyed the quality on my big HDR TV more of course, but overall it is very good.  Thank you for sharing.  I hope you would keep experimenting with HLG.  I would be interested to see your your video from that trip recorded in Rec 709.