`VideoCapture.Open()` is significantly slower on x64 as compared to x86.

[xytec]

Summary of your issue

VideoCapture.Open() is significantly slower on x64 as compared to x86. x64: 5 to 10 seconds x86: 1 to 2 seconds

I noticed this issue was raised but there wasn't a solution.

Environment

OpenCvSharp-4.5.3-20210821 .NET Framework 4.7.2 Windows 10 64-bit

What did you do when you faced the problem?

I ran the sample project provided (Added a x64 configuration).

• \Sample-4.5.3-20210821\VideoCaptureForm

Example code:

paste your core code

Output:

paste your output

What did you intend to be?

[Timocop]

What Capture API do you use? You haven't posted any sample code to reproduce. But i also noticed that - when getting webcam streams - camera.Set(OpenCvSharp.VideoCaptureProperties.FourCC, OpenCvSharp.VideoWriter.FourCC("MJPG")) and VideoCaptureAPIs.MSMF takes a very long time to load (10 seconds) compared to VideoCapturesAPIs.DSHOW which loads instantly. Set the Capture API manually, instead of VideoCaptureAPIs.ANY. This will also remove weird webcam artifacts!

[xytec]

Thanks! Setting it to VideoCapturesAPIs.DSHOW solved the issue.

I was running the sample code provided (The exact project was mentioned in my post above, so I did not think it was necessary to post the code).

[bryansiebert]

It seems to be this issue opencv/opencv#17687 Adding Environment.SetEnvironmentVariable("OPENCV_VIDEOIO_MSMF_ENABLE_HW_TRANSFORMS", "0"); will fix it. Using VideoCapturesAPIs.DSHOW also works but it gave me a much choppier stream

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[alexSmail]

I have the same issue when i run the application using any cpu it take 2sec to laod the camera. when using x64 it takes 14sec!

[ucool-wu]

It seems to be this issue opencv/opencv#17687 Adding Environment.SetEnvironmentVariable("OPENCV_VIDEOIO_MSMF_ENABLE_HW_TRANSFORMS", "0"); will fix it. Using VideoCapturesAPIs.DSHOW also works but it gave me a much choppier stream

It work!