When a video filter returned inf as PTS, the player crashed. One
reason for this was that decode_audio() was called with a negative
minlen parameter, which at some point caused it to call a memory
allocation function with a ridiculous value, triggering an out of
memory code path in talloc.c. (talloc.c has been modified to abort()
on out of memory situations.)
Fix this by sanity checking minlen in decode_audio(). (The check
against outbuf->len always succeeded, because it's an unsigned
comparison.)
Make an existing sanity check in mplayer.c more robust: check for NaN
too, which happens if the video PTS is inf.
This happened with "-vf pullup,softpulldown" (but is not triggered when
the following commit is applied).