DWQA QuestionsCategory: PiVideoFramerate detection
J.G. asked 4 months ago

Dear Lintest Team,
 
I am working with a PiCapture SD1. I use the pivideo_class in several python3 scripts and some analog video sources.
In my case i have the problem with different frame rates of my analog video sources. The frame rates are not well documented by the product manuals of these sources . As a result of this i got some pictures which are not fully colored or not the “right” way at random moments. These picture failures seems to be “lined”. For example the first 2 lines are colored but the rest of the picture got black&white or green.
These problems are rarer by using “raspistill” shell method.
Is there a possibility to detect the framrate by the pivideo software or python module ?
Or are these failures are not caused by the frame rate ?
 
Thank you for your support.
 
Best regard J.G. (Germany)

1 Answers
mwlinder Staff answered 4 months ago

It isn’t clear to us what might be causing this – if you could send an example capture that demonstrates the problem it may provide some ideas.
Usually changes in the frame rate are handled well by PiCapture.   The only exception we’ve seen is with extreme cases when the frame rate results in data rates that are either too slow or too fast for the RPi camera interface.   The frame rate for data supplied to the RPi GPU matches the frame rate of the input video.
There is currently no way to determine the actual frame rate of the video input to PiCapture.   

J.G.Framerate detection