Fixes: 4035/clusterfuzz-testcase-minimized-6479308925173760
Fixes: runtime error: signed integer overflow: 9 * 402653183 cannot be represented in type 'int'

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>