Fixes: signed integer overflow: -1268324762623155200 * 8 cannot be represented in type 'long'
Fixes: 30123/clusterfuzz-testcase-minimized-ffmpeg_dem_THREEDOSTR_fuzzer-6710765123928064
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 7e5034f97e41d3f8112c1f8da3b5274ab99ef6f8)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>