It closes #3512.

It is needed to be sure that the first image displayed after a discontinuity
(flush or seek) is the right one.

First priority is file-extension user gives, if that isn't
specified, use mux-value and if that's not valid (eg mp4), fallback
to flv-muxing.

Doesn't allow mp4-muxer on other than file-output (doesn't check rtp atm).
Also tries to be littlebit clever and cleanup sout-mrl.

Signed-off-by: Christophe Mutricy <xtophe@videolan.org>

Left-over from pre-libtool era

Basicly sets setting to empty or default. Shouldn't affect others than x264-module.

It is faster (and has use a bit of sse2), and better looking IMHO.

It segfaults otherwise.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

It closes #3620.

Untested