Re: VDPAU Error: DISPLAY PRE-EMPTED
From that output it looks like the failing step is the init script trying to run 'git submodule update --init' in the ffmpeg directory. The "shift: 634: can't shift that many" message comes from git; probably the shell script implementing 'git submodule' tries to do something completely nonsensical. As far as I can tell that's a bug in your git version (126.96.36.199 is relatively old). You could try manually running 'git submodule init; git submodule update' in the ffmpeg directory; if it creates a ffmpeg/libswscale directory populated with files then things should probably work. Other than that I can't help as I don't know what git bug you're encountering. You should probably try to get a fixed (newer) git version from somewhere.