Merge commit '56f98e34'

* commit '56f98e34':
  output example: convert audio to the format supported by the encoder

Conflicts:
	doc/examples/muxing.c

Not merged as our example code already does that for what is needed
and we generate matching data for the rest. generating fixed data
and converting all parameters could be done of course.
Merged-by: Michael Niedermayer <michaelni@gmx.at>