The goal is to crop a preview on the surface for frames that come from Camera2 api capture session, but not to crop the video that will be created itself.
For example, I have a streaming resolution of 1920x1080 (16:9), and the screen size (just for instance) 2000x3000 (2:3 -> 6:9 or 16:24, lets pick the second variant for example), so I'd like to have my video in the original streaming resolution - 1920x1080, but my preview to fill all the available space without View resizing - so it should be 5333x3000 (just bumping the size up to fill the rectangle area using the same aspect ratio as the streaming resolution's one), and then to "cut" the "frame data that corresponds to this surface's resolution (which is, I suppose, 5333x2000)" to 2000x3000 (just remove (5333 - 2000) / 2 from both top and bottom).
Is it possible?
P.S.: the bad thing is that google sample for camera2 api resizes the view itself, and these "blank areas" are undesired for me. I haven't found anything that even closely matches my problem.
P.S.S.: AFAIU this SO solution crops the frame that comes from the camera itself, but I need my video to be in the original resolution.
If you're using a TextureView, you can probably adjust its transform matrix to scale up the preview (and cut off the edges in the process). Read the existing matrix, fix up the aspect ratio and scale it up, and then save the new matrix.
But please note that saving a different field of view than what you're showing to the user is probably going to get you negative reactions - please use the preview to frame what they want to record, and if what you're saving has extra stuff, the recorded video won't match expectations. Of course, maybe this isn't a concern for your use case.