Fixed crash playing back videos with unsupported codec (qdm2).
Fixed crash playing back videos with unsupported codec (qdm2).

svn path=/trunk/libavg/; revision=9205

scotty007/libavg,yyd01245/libavg,libavg/libavg,yyd01245/libavg,hoodie/libavg,hoodie/libavg,th3infinity/libavg,libavg/libavg,th3infinity/libavg,hoodie/libavg,hoodie/libavg,scotty007/libavg,yyd01245/libavg,th3infinity/libavg,th3infinity/libavg,scotty007/libavg,scotty007/libavg,libavg/libavg,libavg/libavg,yyd01245/libavg