* src/stream_output/stream_output.c:

* src/stream_output/stream_output.c:
  - for muxers that request some preparsing before starting muxing,
    we now wait for 1.5 seconds worth of data to be in the fifo instead
    of waiting for 1.5 seconds of real-time.
  - if we have have control over the output pace, we also wait before
    starting muxing (produces nicer streams).