Duration in mvex wrong if subtitle track in use

[GoogleCodeExporter]

What steps will reproduce the problem?
1. mux smpte-timed-text tracks
2. find mvex box holding wrong value
3.

What is the expected output? What do you see instead?

What version of the product are you using? On what operating system?

Please provide any additional information below.
Workaround was to circumvent "getTrackDuration" in createMvex if track is of 
type subt.

Original issue reported on code.google.com by christia...@castlabs.com on 16 Oct 2013 at 5:05

[GoogleCodeExporter]

Correction: fragmentDuration in Box mehd (not mvex) is getting the wrong value 
for duration  currently.
Something like 220% of actual video/audio fragment durations. 

Original comment by christia...@castlabs.com on 16 Oct 2013 at 5:13

[GoogleCodeExporter]

please provide an example

Original comment by sebastia...@castlabs.com on 16 Oct 2013 at 9:10

[GoogleCodeExporter]

False alert; If duration of SMPTETT track is set correctly, then values in mehd 
are correct - so everything fine with the tool

Original comment by christia...@castlabs.com on 17 Oct 2013 at 10:09