Hi all,
For one customer we needed a solution to the problem of getting the frames when the video and the graphics layers have been already merged in the DM816x, so in order to solve the problem we ported the writeback driver to the Ridgerun SDK in order to make it work with EZSDK 5.05.02.00 and we created a new camera device in linux (/dev/video7) which allows you to grab the frames using a gstreamer plugin like v4l2src, encode it and save it to a file or just send it through the network. It is important to mention that doing this we are taking advantage of the hardware capabilities (VPSS) to merge the layers and send the frame back to the ARM so it is just 5% or less loaded during the process.
More info:
https://developer.ridgerun.com/wiki/index.php/Writeback_driver_support_for_DM8168
-David