问题
Is there any way using AVFoundation and CoreVideo to get color info, aperture and focal length values in real-time?
Let me explain. Say when I am shooting video I want to sample the color in a small portion of the screen and output that in RGB values to the screen? Also, I would like to show what the current aperture is set at.
Does anyone know if it is possible to gather these values? Currently I have only seen that this is possible with still images.
Ideas?
回答1:
AVCaptureStillImageOutput will get you a real time still from the video stream, including exif data for focal length, aperture, etc. Color info you could calculate yourself from that bitmap.
回答2:
AVFoundation, CoreVideo, and CoreMedia include support for getting a video bitmap in "real-time". From there you can process a portion of the RGB pixels however you want.
I don't know of any current public iOS API to get you the aperture.
The focal length is fixed, but differs between product models. ifixit.com might have that info.
来源：https://stackoverflow.com/questions/3772426/iphone-real-time-video-color-info-focal-length-aperture