Seeing your post, I tried the other two options, namely canvasitems and viewport. But both the settings only limited the window size to the camera, but didn’t affect the black bar at all.
Are you using a sprite sheet or texture Atlas ? Make sure you don’t have neighboring pixels getting UV mapped and resulting in the black bar ? You might be sampling the texels in a neighboring frame kind of thing.
Also! I managed to fix it by opening the file in aseprite normally (NOT by Import sprite sheet) and then I held Ctrl, then I dragged the whole thing upwards by 2 pixels. I saved it and now all the sprite have a vertical offset of 2 pixels by default.
I have had this same issue, and I am almost certain it has to do with the animation player, not the sprite necessarily. I’ve tried to tweak this but to no avail. I am certain it has something to do with how godot renders the sprite sheet you are using when it calculates the key frames.
edit:
I’ve also found this is an issue with the sprite placement on the sprite sheet. If you are using a sheet that has sprites touching, this will cause that problem. It also happens when using animated sprites as well. My workaround was to just separate sprites better on the sheet.