Amlogic Video Engine video playback acceleration

Hello Libre Computer Community,

I am currently experimenting with video playback on Fedora with the Alta. So far I have tried all available video outputs in mpv:

gpu Shader-based GPU Renderer
gpu-next Video output based on libplacebo
vdpau VDPAU with X11
wlshm Wayland SHM video output (software scaling)
xv X11/Xv
sdl SDL 2.0 Renderer
dmabuf-wayland Wayland dmabuf video output
vaapi VA API with X11
x11 X11 (software scaling)
libmpv render API for libmpv
null Null video output
image Write video frames to image files
tct true-color terminals
caca libcaca
drm Direct Rendering Manager (software scaling)
kitty Kitty terminal graphics protocol

None of them are truly video accelerated and only few of them have the correct display resolution or they just don’t work at all. I have tried with VLC aswell, but even then I could observe way to high cpu usage. What is the correct way to playback video on the Alta?

Firefox hw accelerated video playback is affected aswell. AFAIK the vdec driver from Amlogic is integrated into the kernel. I have verified the correct detection of the accelerator with v4l-utils.