Video buffering

I flew Zoe over the weekend with the camera motion running, and it was pretty exiting watching her cartwheel across the lawn – clearly there’s more to do in the testing before I try again!

So I did a passive flight in the ‘lab’ just now and got these stats; I had hoped to show a comparison of the accelerometer measured distances vs the camera video distances, but that’s not what I got:

Motion stats

Motion stats

The lower 2 graphs are the interesting ones: the left one shows how bad the integration error is with the accelerometer – all the details in the accelerometer are swamped by integrated offset errors.  It also shows that we are only getting data from the video every four seconds.

So I did a test with my raw motion code (i.e. no overheads from the other sensors in the quadcopter code), and it showed those 4 second batches contain 39 samples, so clearly there’s some buffering of the 10 Hz video frame rate as configured.

So next step is to work out how to identify whether it’s the FIFO or the video that’s doing the buffering, and how to stop it!