tsdemux: reverse playback support

Submitted by Lori Anderson

Link to original bug (#702595)

Description

I'm working on playspeed support related to mpeg-ts using latest GStreamer-1.X code on Ubuntu 12.4. I have been testing with the GStreamer playspeed tutorial - "Basic tutorial 13: Playback speed" (http://docs.gstreamer.com/display/GstSDK/Basic+tutorial+13%3A+Playback+speed). (See Bug 694369 for code attachment and a sample mpeg2 ts file).

The tutorial fails when attempting to switch to a reverse playspeed. To demonstrate issue, enter "S" to switch from 1x to 2x playback speed. Then enter "D" option to change direction from 2x to -2x rate

I get the following error:
GStreamer-CRITICAL **: gst_segment_clip: assertion `segment->format == format' failed
0:00:39.902699443 11915 0xb5d144f0 WARN mpeg2dec gstmpeg2dec.c:474:gst_mpeg2dec_discard_buffer: Could not find buffer 1822, will be leaked until next reset

Version: 1.x