@Orico4 thanks for the help. I managed to make it work, but now I have different problem.
Setting up pins on Pixracer is not working correctly. Camera is triggered all the time, regardless what are the settings at QGC. Frequency of data is changing by it self, enabling and disabling GPIO pins also does not have any meaning.
Here is also a video when I tried to modify parameters: https://sendvid.com/q80lolda
Any idea what I could do differently?