* qatar/master:
libx264: only use ABR mode when the user explicitly set bitrate.
libx264: use medium preset by default.
mp2 encoder: make 128k the default bitrate.
movenc: use libx264 by default when possible for mov, mp4 and psp
avienc: saner default audio codec.
matroskaenc: saner default codecs.
avplay: add examples of how to specify size/pixel format through private options
lavc: add A|E|D flags to "ac" and "ar" options
Conflicts:
doc/ffplay.texi
libavcodec/libx264.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>