Fix the calculation of the number of frames

Test: make cts -j123 && cts-tradefed run cts-dev -m \
CtsMediaTestCases --compatibility:module-arg \
CtsMediaTestCases:include-annotation:\
android.platform.test.annotations.RequiresDevice

Bug: 64730503
Change-Id: Ie858a52cf7267b3783f67ca378a8c5efb726495c
1 file changed