Scaling and whitelist

  • Hi. I use Libreelec 10 on a Raspberry Pi 400 connected directly on a Benq HT2050A projector (Full HD). Everything works great except this problem where the projector would go black for about 7 seconds each time I play a video. I'm using the delay video option but that doesn't seems to work correctly for playlists. Reading around it seems this is caused because the two parts need to work out resolution and/or refresh rate if I understood correctly. The solution to this seems to be to use the whitelist option. I checked the whitelist section, and I get alot of modes in there to choose from.

    In general, is it better if the scaling is done by the Pi or the projector? Lets say I have a 480p video, if I whitelist this mode, Libreelec will send it to the projector as is (from what I understand), and the projector will do the scaling to 1080p. If I don't use whitelist at all, the Pi will do the scaling to 1080p and then send it to the projector. Any difference on picture quality between these two cases? If the scaling is done by the projector, is it taxing for the projector, it gets hot as it is and I don't want it to release even more heat in the room, especially during summer. Thanks.

  • Projectors generally switch resolutions slower than TVs do so the goal is to eliminate or minimise the refresh rate switching. So lets assume you mostly play DVDs/Movies which have a native 23.976Hz refresh rate; set the Kodi desktop to [email protected] and now there is no transition when playing media. You will still see it when e.g. playing PAL media (25Hz). The alternative is to switch Kodi to 1080@60 and disable the whitelist and adjust-refresh completely, and all media will be upscaled/adapted to 1080@60. You might see the occasional glitch in playback but generally Kodi handles this well, and as the picture on a projector is not as sharp as an LCD/OLED panel you probably won't notice.

  • Thank you very much chewitt. So the culprit is refresh rate. Disabling adjust-refresh completely seems like a solution. Will experiment a little and report back (with a question or two more likely) :)