nutdec: check for negative frame rate in decode_info_header

A negative frame rate triggers an av_assert2 in av_rescale_rnd.

Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 6621105877ce0d65724a8ab60b3a50160adbe65d)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
1 file changed