The Trial version of MixCast is capped to 1280x720 resolution but our full offering supports rendering at up to 4K. The only limitation on this is that for titles without the MixCast SDK (that are instead providing MR through the SteamVR SDK), your experience render resolution is limited to 1/2 the resolution of your active monitor. This means that you would need a 4K monitor to produce 1080p output with a non-MixCast-SDK title.