wtvdec: prevent memory leak in get_tag()
rv10: always check direct mode interpolation times.

Fixes Division by 0

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
rmdec: Limit videobufsize to remaining amount of data

Fixes excessive memory allocation

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>