Troubleshooting OpenCL

PROBLEM

I'm having problems with exporting/processing images.

My images have artifacts in them when viewing/processing.

Processing/viewing images is slow.

SOLUTION

The quickest way to see if OpenCL is causing these issues is to set it to 'Never' under Preferences > General. For more information, see below:

The issues described above are usually associated with OpenCL (Open Compute Language) which enables the effective utilization of thousands of computing units within modern graphics cards. For Capture One, only relatively new GPU cards have enough computing power and onboard RAM to be utilized effectively. Whilst OpenCL is designed to increase performance in Capture One, you may also find some instances when it can decrease performance instead or cause some issues while processing and editing images. Such issues usually occur on the machines which do not meet our recommended system requirements for running Capture One. You can find those system requirements in the release notes for the particular version of the Capture One software you are using.

The issues that might be related to OpenCL

• Scrambled or somewhat 'glitched' previews when making adjustments
• Crashes when processing/exporting images
• Artifacts in processed images
• Slow processing times
• Slow mask drawing
• Crash when opening Capture One

How to define whether OpenCL is initialized?

• Ensure that OpenCL is set to 'Auto' in your Preferences.
• Reset adjustments on an image.
• Enable the focus mask by going to View > Show Focus Mask in the Capture One main menu.
• Slide the exposure slider gradually.

If the focus mask is disabled while you are increasing your exposure, OpenCL is being utilized. If it remains visible while making these adjustments, then OpenCL has failed to initialize or is not in use.

If Hardware Acceleration is stuck at 0% on initialization (Windows OS)

This is an access issue with Capture One enumerating installed OpenCL platforms. You can fix that by following the steps below:

• Close Capture One, then hold down the Windows key and press the R key on the keyboard.
• Type regedit in the window. This brings up the Registry Editor.
• Select Yes to make changes.
• Go to Computer -> HKEY_Local_Machine -> SOFTWARE -> Khronos -> OpenCL -> Vendors.
• Right-click on IntelOpenCL64.dll and choose Modify.
• Enter "1" (without the quotes) in the Value data field. Press OK.

NOTE (for AMD Radeon RX 5700 graphics card users) 

Delete the version-specific preferences folder:
C:\Users\UserName\AppData\Local\Phase_One\CaptureOne.exe_StrongName_y3yh4brhpfi14u41fltdrpfruizxirsn
The last part \(...)_Strongname_(...) might be different for you.

Then restart the computer and Capture One. That way, Hardware Acceleration should be fully initialized.

Learn how to find the AppData folder on Windows

Rebuilding kernels

If you have a machine that meets our recommended system requirements, you may need to rebuild the kernels needed for OpenCL to initialize properly.

Capture One 20.0.0 and later versions

macOS

Close Capture One and then delete the contents of the ImageCore folder as shown in the image below. You can find this folder by navigating to ~/Library/Application Support/Capture One/ImageCore (this can easily be done in Finder via Go > Go To Folder menu item). When you restart Capture One, OpenCL will rebuild the hardware acceleration kernels- let it finish before quitting the software. This rebuild will only need to be done once.

Windows

Similar to the procedure on macOS, delete the contents of the ImageCore folder and restart Capture One, whereby OpenCL will re-initialize.

C:\Users\User_Name\AppData\Local\CaptureOne\ImageCore

Learn how to find the AppData folder on Windows

Capture One 12.1.5 and earlier versions

macOS

Close Capture One and then delete the contents of the ImageCore folder as shown in the image below. You can find this folder by navigating to /Users/Shared/ImageCore (this can easily be done in Finder via Go -> Go To Folder menu item) When you restart Capture One, OpenCL will rebuild the hardware acceleration kernels- let it finish before quitting the software. This rebuild will only be done once.

Windows

Similar to the procedure on macOS, delete the contents of the ImageCore folder and restart Capture One, whereby OpenCL will re-initialize.

Disable OpenCL in Capture One

General guidelines

If viewing, processing, or exporting issues still occur, set the OpenCL options to Never in the General tab. Navigate to the Preferences -> General -> Hardware Acceleration (Use OpenCL for) and set the Display and Processing options to Never. Restart Capture One.

Disable OpenCL in Capture One in case of a crash at startup 

• Windows: Run the script DONOT_useopencl.reg and restart Capture One (the download also contains a restore script to re-enable OpenCL useopencl.reg)  Download here.
• MacOS: Download AdjustOpenCL_External.zip and run this application AdjustOpenCL_External.app, disable OpenCL, and restart Capture One.