[Interest] QVideoFilter questions

[Jason H]

I'm trying to use this new (5.5) class for some very basic video frame analysis.  (Like, average and stddev luminance values) I wish to use the Filter class in QML.

I have a few questions:
1. I want to support as many mobile devices as possible. What are the pixel formats that I must support? Is there a list of what devices use what pixel formats?

2. From the docs - "For filters that only calculate some results and do not modify the video frame, it is also possible to operate asynchronously. They can queue the necessary operations using the compute API and return from this function without emitting any signals. The signal indicating the completion is then emitted only when the compute API indicates that the operations were done and the results are available." I wish to do this. 
- What does that look like? 
- What "compute" API? 
- How are the results communicated back to QML?