swr: fix handling of timestamps that cause multiple drops or silence injections

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
ffplay: fix sws_flags

Fixes Ticket45

Reviewed-by: Marton Balint <cus@passwd.hu>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
h264: fix () placement

Fixes null pointer dereference

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>