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DUT / automatic video content glitch testing

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Joined: November 7th, 2020, 4:26 am
Country: Germany

DUT / automatic video content glitch testing

Post by Sefa.aydemir » November 7th, 2020, 5:13 am


we have a GV Kayenne switcher that produces glitches in the video output of its image store when in E/E Mode and is passing through a live signal. That happens maybe 5 to 10 times within a production day. We use this device to pass through e. g. a 1080i25 signal and want to produce a typical "film-like" look through discarding one field of video and double the other (e.g. discard field 2 and double the lines of field1). This results in a temporal half framerate in means of the motion in the content leading to the desired film-like "stutter". We are aware that this reduces the vertical image resolution to to the half of the original camera signal, but this is ok for our custumers.

For the last few weeks we now see a specific error in our recordings of that output after someone has seen a glitch in the live program of that image store output (we are not able to reproduce it as we don't know the cause of the problem). It is a matter of coincidance that someone sees it and then we can have a closer look on our recordings.

What exactly happens?
Instead of playing out the frame sequence in the right order like this
1-2-3-4-5 etc.
it plays out
I hope it gets clear.

We would like to Test some spare parts of the switcher, but we have to be sure, that the error has been fixed and does not occur the next production date. But it is nearly impossible for a human eye to keep track of every frame for ours, not even for 20 seconds, if you can't predict WHEN the error occurs (if at all).

My question is, what kind of test equipment can do that test observation for maybe one day and report every one of that glitch.

It has to be said that this is not a matter of technical SDI stream analysis in a manner of the singal/stream structure. The technical aspect of the SDI signal are fine, it is just a repeated frame and thus clearly just a "wrong" content in one frame, that we see.

Does anybody know, how we can automate a test, that maybe compares each Input frame with its respective output frame and reports the error (delta CONTENT in input to output) in some kind of log file. With that, we could maybe finde the defective part by subsequently replacing parts of the switcher instead of buying a complete new switcher.

Does Tektronix offer such equipment? Or any other vendor? Or is there a way of "DIY" test scenario that can accomplish this task?

I know there are much more sophisticated analysis devices out there (e. g. PQA500 for every kind of image processing down to simulated human visual perception and even more) but my task seems to me like a very simple thing to achieve regarded those. I belive the PQA500 could do it, but with all the documents on the web about it, I am not able to identify a workflow that aims at what we have to accomplish. Its just to complex for me. I need a hint from the specialists.

Any help appreciated!

With best regards
Sefa Aydemir

Posts: 33
Joined: September 1st, 2018, 11:27 am
Country: Greece

Re: DUT / automatic video content glitch testing

Post by Kiriakos » November 11th, 2020, 11:47 pm

Down to plain troubleshooting, I would worry about the power supply of your GV Kayenne switcher.
And I would add also one uninterruptible power supply (UPS) at the ACV side for max protection against Mains voltage fluctuation.

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