When 'out' is an AVFrame that does not have buffers preallocated,
swr_convert_frame tries to allocate buffers of the right size. However
in calculating this size it failed to check for whether 'in' is NULL
(requesting that swr's internal buffers are to be flushed).
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Based on commit fb1ddcdc8f by Luca Barbato <lu_zero@gentoo.org>
Adapted for libswresample by Michael Niedermayer
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
