[MaxiHori]

I have a projector attached to my computer (HDMI) and I want display Kodi in it like if it was a second monitor.

The projector is a Optoma HD131xe W and it's native support is 1920x1080
but whenever I go over 1366x768 (only in fullscreen mode, while windowed it works) It's like I can only see 1/4 of the screen upscaled to full screen

here's a pic:

[PatK]

I'm not sure what O/S you're using, but if you make the 2nd display (projector) your desktop and resize 1080p using the gfx card software, then launch XBMC in windowed mode, then adjust in settings 1080p full screen to match you should be good. Be sure the projector is on before you switch displays, otherwise you'll get a default size similiar to what you mentioned.

[MaxiHori]

I'm not sure what O/S you're using, but if you make the 2nd display (projector) your desktop and resize 1080p using the gfx card software, then launch XBMC in windowed mode, then adjust in settings 1080p full screen to match you should be good. Be sure the projector is on before you switch displays, otherwise you'll get a default size similiar to what you mentioned.

I made my projector the primary screen (and disabled the other one), resized to 1080p and then opened XBCM in windowed mode, everything fine. But as soon as I place it in full screen I get the same issue

[PatK]

This could be the overscan settings in the projector itself, In XBMC.Kodi going into settings/system there are tools to enable size within the given gfx card parameters, make sure you have a look. I guess what is perplexing is that you have a desktop sized correctly on the proj, yet when going full screen it's over-scanned. There is a possibility that the momentary switch from desktop to full screen causes a loss of the video signal whihc kicks in the default settings sent back to gfx card.

[MaxiHori]

This could be the overscan settings in the projector itself, In XBMC.Kodi going into settings/system there are tools to enable size within the given gfx card parameters, make sure you have a look. I guess what is perplexing is that you have a desktop sized correctly on the proj, yet when going full screen it's over-scanned. There is a possibility that the momentary switch from desktop to full screen causes a loss of the video signal whihc kicks in the default settings sent back to gfx card.

Must be this! The moment that I change to full screen the projector shows it's own loading button and it act like if it has lost the signal and it's taking it back. you must be very knowledgeble o_O
But I don't quite understand what im supposed to do, I can only see some basic settings in Kodi

[PatK]

Your solution will revolve around the projector and tweaks, In the desk top resolution you should see what the EDID sends as available resolutions in your Proj which is not the default. The idea is either to create a new default in the proj or fool it into using the supplied res. This get's complicated real fast there is a possibilty that a custom driver or some hardware inbetween solution might be able to hold onto the res, but I don't have any working experience to relate other than to suggest you ask in A/V forums or the manufacturers for work arounds.

The only other suggestion I could make is to use windowed mode, I have seen some solutions for hiding the a window frame somewhere in the forums.

[MaxiHori]

Your solution will revolve around the projector and tweaks, In the desk top resolution you should see what the EDID sends as available resolutions in your Proj which is not the default. The idea is either to create a new default in the proj or fool it into using the supplied res. This get's complicated real fast there is a possibilty that a custom driver or some hardware inbetween solution might be able to hold onto the res, but I don't have any working experience to relate other than to suggest you ask in A/V forums or the manufacturers for work arounds.

The only other suggestion I could make is to use windowed mode, I have seen some solutions for hiding the a window frame somewhere in the forums.

I did some test and the projector loading screen did not appear when switching from windowed to full screen mode like I said before, but only when changing resolution.
I found the EDID control panel in my video drivers and I applied "1080p60 standard" and the projector showed the loading button and then 1920 x 1080 @60Hz so it seems working as it should be.

I noticed that If I place Kodi in window mode but taking all the space available (like full screen but with borders) and then choose the "calibration" option it shows that in windowed mode it is using 1280x670 as a resolution,
but at the same time when I see the screen property in windows it still says that im using 1920 x 1080 3D.
So I can't even do that trick of keeping it in windowed mode since even in windowed mode the resolution is wrong!

The projector doesn't have any settings for resolution, so if it is not a Kodi problem than my only option would be the graphic card drivers but if I use VLC for example I can totally use the fullscreen mode in full hd resolution.

Don't know how to identify the problem here

[PatK]

If VLC plays out correctly than something is amiss. There really shouldn't be any issue with the drivers, but that re-sync of video is where it starts. When I go into video re-calibrate I get 1920x1167 (1920 x 1200 monitor) and 1920 x 1047 (TV in windowed mode). Question is what gfx card & software, check your O/S display modes vs GFX settings and make sure they're all in line. Obviously if you have a 1080p sig, and the desktop is 1080p and the proj is setting 1080p something is setting this all back to default much lower.

Of course you could use VLC as an external player, not the solution but a workaround. Quite a few XBMC/Kodi skins interfaces are 720 but they play back 1080p video in the player, but I doubt this is in play here.