Mp4: allow end values bigger than track duration.
Mp4: allow end values bigger than track duration.

If start time is within the track but end time is out of it, error
"end time is out mp4 stts samples" is generated.  However it's
better to ignore the error and output the track until its end.

firebase/nginx,hy0kl/nginx,hy0kl/nginx,firebase/nginx,firebase/nginx,hy0kl/nginx,firebase/nginx