am 2f9a1ce2: When checking the current playback position against the length of the file, make sure the length is valid. Otherwise we can end up endlessly (recursively) calling next(), and run out of stack.

Merge commit '2f9a1ce2f3b0ae72d698c240ce8448bc7cfe3a77'

* commit '2f9a1ce2f3b0ae72d698c240ce8448bc7cfe3a77':
  When checking the current playback position against the length