HW accelerated video decode matrix

RPI:

• h264: hw decode & hw compose, low latency. needs "fkms" enabled on rpi 4
• h265: hw decode & gpu compose (Pi 4 only), medium latency
• mjpeg: sw decode & gpu compose, medium latency

X86:

• h264: sw decode & gpu compose, low latency (on devices with good cpu compute power)
• h265: sw decode & gpu compose, low latency (on devices with good cpu compute power)
• mjpeg: sw decode & gpu compose, low latency (on devices with good cpu compute power)

Other platforms: sw decode & gpu compose should always be available as fallback.

You can also always use QOpenHD with a transparent background and start your manual video decode pipeline in a window behind. (requires X server)