System information (version)

• OpenCV => opencv-python 4.5.5
• Operating System / Platform => win10
• Compiler => pre-compiled

Detailed description

Currently, it always needs FFmpeg/FFprobe to extract frame type info before any future processing, but calling a new process is slow and complex for other codes.
I,P,B frame type info could be useful to do some scene-change detection.

But OpenCV currently misses the function to get that info, but it should be there when OpenCV reads the video files.
Could OpenCV enhance this feature?

Thanks

Steps to reproduce

N/A

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