How to handle negative dvb pcr changes in gstreamer

[abdus_salam]

Hi,

First of all, I asked the same question on stackoverflow a few days ago and
as there is no response yet, I decided to post it over here. To avoid any
confusion, here is the link for the original question
http://stackoverflow.com/questions/34786975/how-to-handle-negative-dvb-pcr-changes-in-gstreamer

On our gstreamer pipeline which plays DVB streams, we are calibrating the
system clock with PCR values from the stream. However, when the stream wraps
(looping a recorded stream use case) or a broadcaster decides to change the
PCR base to a value smaller than the current one (allowed in the spec), I am
not quite sure how this should be handled because, due to its monotonic
nature, clock freezes until it catches up with the last value.

One workaround I can think of is, first calibrating the clock to max clock
value, then let the clock overflow and recalibrate it with the new PCR. Is
this a valid thing to do? I presume the pipeline elements are designed to
cope with clock wraps.

The other question is, what does 'GST_CLOCK_TYPE_OTHER' actually mean? As on
our target platform we use gst 0.1, I can't quite test it but I wonder if
setting this for the default system clock allows non-monotonic operation
(i.e. negative jumps) on 1.x?

Regards,





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