We may or may not be able to play the latter parts
but not demuxing at all seems like the worst possible behaviour.
Fixes playback of e.g.
http://playlist.yahoo.com/makeplaylist.dll?sid=128114687&sdm=web&pt=rd
As a proper solution either multiple video streams should
be exported or side data should be used to update extradata
if necessary.
Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>