The easiest way to know if your videos are playing with GPU acceleration are to watch the process of xplayer, mpv or whatever you are playing. The CPU usage should be no more than 10% for that process/program if it is using acceleration.
Let's manually play with vdpau to make sure it works before we make it permanent:
First make sure you have libvdpau installed:
sudo apt install vdpau-driver-all
I'm having trouble making it work on very shaky video the result seems kind of warped/blurry/fish eye like and not as good as some other examples I've seen:
ffmpeg -i MVI_1285.MOV -vf vidstabdetect=shakiness=10:accuracy=15 -f null MVI_1285.trf
ffmpeg -i MVI_1285.MOV -vf vidstabtransform=smoothing=30:input="transforms.trf" MVI_1285.MOV.mp4
I've played around with the shakiness, accuracy etc.. but not the smoothing part.........
#if you have nvidia make sure you install the nvidia-cuda-toolkit so hardware acceleration can be used
tar -jxvf ffmpeg-3.3.2.tar.bz2
install prefix /usr/local
source path ........