libcamerasrc / gstreamer plugin expose sensor-mode configuration

[Jeffrey Katz]

Hi Jacopo & co,

> True that's what rpicam-apps do, and you will probably be able to do the same
> by enumerating the RAW modes. However you won't be able to test the frame
> durations without configuring the camera, which I'm not sure it's something
> that we want to be done in the "enumeration"
> phase...

I honestly see this as two separate functionalities:

1) Be able to specify, through some means, how the sensor should be accessed
2) Discovery of what exactly is possible with a given sensor

As I understand the discussion so far, 2) is difficult because the kernel interfaces are not yet there, creating a chicken-and-egg problem. However, I still don't understand what is preventing 1) to be independently added. Especially in our case, we know in advance what exactly we want, we're just unable to specify it. If this means an intermediate period where the rpicam-apps have to be used to discover what to set, that's okay in my book. Especially as it doesn't change anything for existing users.

-JK