avformat/tta: fix crash with corrupted files
av_add_index_entry() can fail, for example because the parameters are
invalid, or because memory allocation fails. Check this; it can actually
happen with corrupted files.
The second hunk is just for robustness. Just in case functions like
ff_reduce_index() remove entries. (Not sure if this can actually
happen.)
Fixes ticket #4294.
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit
6a0cd529a35190d9374b0b26504e71857cd67b83)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>