Fixed a video editor crash due to "divided by 0"

The crash was because the video sample was too short and has 0 duration (or a single frame video).
This patch is just simply not to support 0 duration video for editing.

Change-Id: I2c7ff78b1e884a4d3a5051f87cdbeeb5dc3078a6
related-to-bug: 6670656
1 file changed