This fixes segmentation faults caused by passing a packet_ptr of NULL to
memcpy.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
(cherry picked from commit 40eb2531)
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>