Hello, I tried many times to export videos but it always export with a black background or like if the video was downsized. I tried to change every parameters but it never solved.
Can anyone help me ?
Picture of the bug / problem :
Not a bug, just make certain that your video mode settings (Settings>Video mode) match the video before you import the video
Thanks it works now 
but why does the automatic video mode isn’t working ?
‘Automatic’ works fine (I use it 99% of the time), but it set’s the project’s ‘settings’ relative to the first video clip imported.