This is needed especially for AV1: If a reformatting error happens (e.g.
if the length field of an OBU contained in the current packet indicates
that said OBU extends beyond the current packet), the data pointer is
still NULL, yet the size is unchanged, so that writing the data leads
to a segmentation fault.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>