as for the media_modules repo your linked did you try it ? the code is oriented for the 4.9 mainline kernel if I understand, but the mainline kernel still lacks alot of things.
Maxime Jourdan is doing some great work in the media part of the mainline kernel but his patches haven't made their way to the stable tree yet, so we need to wait I guess.
I haven't tried but I would like to do. I'm not a kernel developer so if the code needs heavy changes to compile I may can't do it.
The linked code can hw decode all formats via dvb layer. It's not for the mainline kernel, it's for amlogic special kernel (4.9) and it may compatible with 3.14. If it works we don't need the userspace stuff.
For the first look it can easily put the drivers/amlogic dir and I think I need to remove existing dvb codes, then I could compile it without the avl frontend driver. Then I could test it with the gstreamer dvbsink plugin.