System Information

N/A, issue affects all platforms and distributions of 4.11.

Detailed description

It appears that commit 305b57e (backporting changes from 5.x) changed the default value of CAP_PROP_ORIENTATION_AUTO. I noticed the issue since I have some open source projects that relied on this being turned on by default.

The value now seems to be disabled by default:

Previously, it was enabled by default:

For users of my project, this means if they update to the latest version of OpenCV, frames extracted from the video are no longer rotated correctly. Was this change intentional? I could not find any references to these changes in the changelog.

I noticed this change due to tests in one of my projects which verifies that videos are autorotated based on metadata. Although a workaround could be to set CAP_PROP_ORIENTATION_AUTO explicitly, I have several projects which relied on this being enabled by default. Performing auto rotation by default also seems like a reasonable choice for an API, since there already was an explicit opt-out mechanism. I suspect changing this may break other existing applications as well.

Steps to reproduce

There appears to be a rotated video present for the test cases in modules/videoio/test/test_orientation.cpp. However, none of the existing test cases demonstrate/validate the expected default of CAP_PROP_ORIENTATION_AUTO. It's probably worth adding a test for this to prevent any regressions (it should be possible to determine if a backend supports it at runtime), and also to update the documentation accordingly.

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues, forum.opencv.org, Stack Overflow, etc and have not found any solution
• I updated to the latest OpenCV version and the issue is still there
• There is reproducer code and related data files (videos, images, onnx, etc)