EDIT: Too slow, but don't want to delete the whole text. took me some time
Okay here we go. In the comment section under Souls Unsqueezed in steam forum someone explained in pieces how to get rid of the black bars. This method worked now 3 times in a row for me (load game, close game, start again, and so on)
(description is for 21:9 2560 x 1080)
( not needed - modify your ds3.exe and replace 398EE33F with 26 B4 17 40 (already known from other games))
- modify your ds3.exe and replace 800700003804 with 000A00003804 (this will make possible to set 2560 x 1080 in window mode. without the change you can only set it to 1920 x 1080)
- modify your GraphicsConfig.xml (appdata - roaming - dark souls III) to:
<config><ScreenMode>
WINDOW</ScreenMode>
<Resolution-WindowScreenWidth>2560</Resolution-WindowScreenWidth>
<Resolution-WindowScreenHeight>1080</Resolution-WindowScreenHeight>
- download "windowed borderless gaming" and install it
OR you can set your GraphicsConfig.xml to read only and change to fullscreen later in game options
- start dark souls 3, it should start in window mode. check in options if the resolution is set correct (
http://i.imgur.com/T9zWu1U.jpg )
- load your game (you should see some flickering image on the right side while the item descrition is displayed)
- it should now load without the black bars.
- click your windowed borderless gaming icon in your task bar. add window, click back to dark souls 3 and press f3
OR as mentioned, set the game in options to fullscreen.
game should be now in fullscreen without any black bars
testet it right now before posting a fourth time and it loaded again without black bars.
EDIT: DSR works as well. When you set your GraphicsConfig.xml to read only and don't use "windowed borderless gaming" to "force" fullscreen you can set your game to fullscreen in options an choose whatever resolution you want to. If the game is started without the black bars, the bars won't come back until you restart it, independent which resolution you are choose