Diagnosing Frame Sync Issues?

[Stirling Westrup]

This may, or may not, be a GStreamer issue. I've written a video-wall
application that splits a playing video into pieces and shows the pieces on
zero-clients connected to the host computer via USB or Ethernet cable.

This basic functionality is working, but when playing large (ie 4K
resolution) videos, we sometimes see momentary differences between when
different monitors get updated with the next frame of video.

Now, I can easily imagine a number of places that a video frame may be
delayed so as to show after its neighbor:

1) Inside the GStreamer pipeline.
2) Inside the network stack
3) due to USB bandwidth issues.

So far the only code in GStreamer that tries to maintain sync is that in
the queue that handles each output monitor. The assumption made was that
that would be sufficient. I could (with a lot of rewriting) replace all N
output queues with a single N-way multiqueue, but I'm unsure that such a
move is actually necessary.

Does anyone have any suggestions of ways, techniques, whatever to try to
narrow down cause of the frame sync issue before I go rewriting great
chunks of code. I would hate to do all that just to find out it was a USB
driver issue all along...

-- 
Stirling Westrup
Programmer, Entrepreneur.
https://www.linkedin.com/e/fpf/77228
http://www.linkedin.com/in/swestrup
http://technaut.livejournal.com
http://sourceforge.net/users/stirlingwestrup
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