Allows PCR<=>PTS<=>offset estimation/calculation
Right now the calculation is very naive, but can be extended later on
without disrupting the code in tsdemux/mpegtsbase
* Don't take into account packets that arrived at the same time as
previous ones for clock skew estimation
* Add convenience method for processing the next ts packet
This is probably the cause for an occasional crash while streaming
MPEG. Blind fix after staring at the code and following logic, so
may or may not fix the issue, I cannot test.
(Port of 4275a70cb5 from mpegdemux)
buffer timestamps are converted to GstClockTime to cover pcr/pts wraps.
multiple pcr/pts wraps are handled with an index which ensures at most
a single pcr wraparound between two entries.
the last seen pcr is recorded to have a nearby index point for short seeks
resuming playback might be delayed if the postion is not a keyframe
TODO: replace manual packet scanning and parsing in the initial duration estimation
