StageVideo sample compiles but doesn't play anything

[f-rank]

Tried some examples from the sample directory.
At first I thought it was the empty link the example is pointing to, but after changing it to another .mp4 location or trying to play local video, while adding some traces to see if it is executing, it looks like it is running through without anything happening.
Maybe missing something here and it needs some specific codec in the .mp4 ?

[thomasuster]

This is what I see which also looks unintended. @hughsando any ideas?