mpegtsdemux: Confused when receiving segment updates from upstream

Submitted by Guillaume Desmottes @gdesmott

Link to original bug (#734024)

Description

I'm working on implementing DLNA time based fast forward. The idea is to implement fast forward in dlnasrc by requesting smaller parts of the file to the HTTP server. Dlnasrc then sends segment updates for each fragment of the file to play (for example, if rate=2 and we use chunk of 1 second we could have something like [00:00, 00:01] then [00:02, 00:03] then [00:04; 00:05]).

This works fine with mpegpsdemux but not so much with mpegtsdemux. With 1.4 playback just stops when starting the fast forward.
With this patch http://cgit.freedesktop.org/~bilboed/gst-plugins-bad/commit/?h=trickmodes&id=bcde22f243a4cc6e053b7d89a435ee021d237214 playback is fine but the reported time is wrong (the position slider in playback-test is always stuck between the 2 same values).