am eff30e3d: Change the default time scale for audio/video track during recording and reduce rounding errors in calculating the sample duration

Merge commit 'eff30e3d1b005fd0696390d1dd47ec4ff0c52784' into gingerbread-plus-aosp

* commit 'eff30e3d1b005fd0696390d1dd47ec4ff0c52784':
  Change the default time scale for audio/video track during recording