I pushed an update with some minor performance improvements. It might cut half a second off of channel loading lol. This only applies to apps that are not running in compatibility mode.
Overall I don’t anticipate there being anything else that can be done to speed things up further.
If speed is your primary concern you should buy the fastest android device you can, configure it to never sleep, and only tune channels from one app so that app can sit idle in the foreground.
I looked into building some sort of “keep alive” feature that would keep all of the tuners awake with the most frequently used app in the foreground. However, this process would have to lock each tuner as it runs and in itself would end up delaying tuning actions from time to time. Not worth it IMO.
Edit: With further testing this is working very well. At least with YTV when it's already open.
Device: Chromecast with Google TV (4k)
INFO:root:Tuner: Tuning completed in 2.55 seconds. Display was on, application (com.google.android.youtube.tvunplugged) was running.
INFO:root:Tuner: Tuning completed in 2.22 seconds. Display was on, application (com.google.android.youtube.tvunplugged) was running.
INFO:root:Tuner: Tuning completed in 2.38 seconds. Display was on, application (com.google.android.youtube.tvunplugged) was running.
INFO:root:Tuner: Tuning completed in 2.2 seconds. Display was on, application (com.google.android.youtube.tvunplugged) was running.