Logitech Brio and HDR

[Fast Draw]

Hi, I am trying to get an HDR picture/video out of the Logitech Brio (which is advertised as "HDR").

I have noticed

• If I set Color Format to P010 and Color Space to Rec. 2100 (PQ), this will result in HDR video.
  
  
• However, it doesn't seem to matter if the input source is actually HDR or not. In the video capture device, if I set the color space to something non-HDR, like Rec. 709, this will also result in an HDR recording. Also, if I switch out the Brio for a different webcam, that is not advertised as HDR, it will also result in an HDR recording.
  
  

It seems that I have no way to confirm if the picture coming from the video capture device is really HDR. Or am I thinking about this wrong? I have tried to raise this issue with Logitech support, but they told me (this is a direct quote, including typo(s)):

OBS supports HDR function and i can confirm that it allows recording in HDR, but I am not able to inform you how to adjust the settings for HDR streaming as this is a third party software and we do not support it officially.

 

[Suslik V]

OBS Studio can output either HDR (>8-bit depth per channel) or SDR (=8-bit per channel). Your content can be 8-bit, but the output (file) still will be 10-bit per channel if you set corresponding Setting>Advanced>Color Format in the OBS itself (the program "converts" 8-bit video source into 10-bit internally, on the fly).

There are number of changes in the code, so next OBS release can has better support of your camera device. For example:

win-dshow: Ignore FFmpeg colorspace if overridden by jpark37 · Pull Request #7880 · obsproject/obs-studio

Description Verified MJPEG devices are no longer locked to Rec. 601. Motivation and Context Want to be able to have more accurate colors. How Has This Been Tested? Verified matrix override works no...

github.com

Some encoders not compatible with HDR and can store only 8-bit data.

 

[Fast Draw]

Does this mean that OBS will just create HDR out of any input source, regardless of whether the source is HDR or not, but not give any indication if the source is HDR?
I just tried the beta (29.0 Beta 2 Pre-release) with the changes you menationed included, but I do not see a difference on the user interface side. I can still seemingly choose any color space for any webcam, including HDR (Rec. 2100 PQ), regardless of what the webcam might actually support or not.

 

[Suslik V]

This means that OBS can compose the 8-bit sources together with the 10-bit sources in any combinations. It is universal.
The output "bitness" of OBS is determined by the Setting>Advanced>Color Format setting. In other words, this setting sets the "bitness" of the canvas where you adding your video sources.

The info window (or log-file info) that can point to all properties of the captured source (including its "bitness") - I didn't heard about it yet. Some additional info is available only for the developers during the program creation/debugging but it is not designed to be viewed by end users.

 

[Fast Draw]

There is no indication about the video capture device's color space in the log file. Is there a verbose logging perhaps?

This is all I'm getting:

12:18:50.599: [DShow Device: 'Brio new'] settings updated:
12:18:50.599: video device: Logitech BRIO
12:18:50.599: video path: \\?\usb#vid_046d&pid_085e&mi_00#6&1218e25c&1&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global
12:18:50.599: resolution: 1280x720
12:18:50.599: flip: 0
12:18:50.599: fps: 60.00 (interval: 166666)
12:18:50.599: format: MJPEG
12:18:50.599: buffering: disabled
12:18:50.599: hardware decode: enabled
12:18:50.651: using video device audio: no
12:18:50.651: audio device: Microphone (Logitech BRIO)
12:18:50.651: sample rate: 44100
12:18:50.651: channels: 2
12:18:50.651: audio type: Capture
12:18:50.658: [rtmp-services plugin] Remote update of URL "https://obsproject.com/obs2_update/rtmp-services/v4/package.json" failed: The requested URL returned error: 404
12:19:22.707: ---------------------------------
12:19:22.708: [DShow Device: 'Brio new'] settings updated:
12:19:22.708: video device: Logitech BRIO
12:19:22.708: video path: \\?\usb#vid_046d&pid_085e&mi_00#6&1218e25c&1&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global
12:19:22.708: resolution: 1280x720
12:19:22.708: flip: 0
12:19:22.708: fps: 60.00 (interval: 166666)
12:19:22.708: format: MJPEG
12:19:22.708: buffering: disabled
12:19:22.708: hardware decode: enabled
12:19:22.734: using video device audio: no
12:19:22.734: audio device: Microphone (Logitech BRIO)
12:19:22.734: sample rate: 44100
12:19:22.734: channels: 2
12:19:22.734: audio type: Capture

 

[Suslik V]

No. That's all you have right now.

As for your device (Logitech BRIO, model number: V-U0040, if I understand it right), the manufacturer's site says that the device has 8-bit per channel colors, and only 8-bit colors.

Color Graphics

8-bit color system

If this info is correct, then it means that the output from the device is SDR (8-bit). But internally, camera may use advantage of the 10-12-"any_number"-bit ADC that digitizes the light information from the sensor. Later this data converts (read truncates) to 8-bit colors at decent level of brightness in halftones under the various lighting conditions. And this technology can has name RightLight. The last is only my guess of course, you may contact manufacturer to get more clear info if your product can actually output the 10-bit colors.