Decoding

THIS SECTION ONLY APPLIES TO PRE-1.0 DISCORDCOMPRESSOR

"Decoding": {
	"HardwareAccel": "auto",
	"TonemapHWAccel": true
},

HardwareAccel

Same as in FFmpeg. auto should be fine, you can try cuda (NVIDIA) or qsv (Intel) for a potential speed boost. If your CPU is fast enough, disabling hardware accel (none) will also speed things up, especially on the 1st pass.

TonemapHWAccel

Applies to HDR videos. Needs an OpenCL-capable GPU and OpenCL support in your ffmpeg build. Disable if you're having flickering/colour issues in HDR videos.