Thanks for the advices!
Anyone who doesn’t hear the difficulty of detecting sound, I noticed in the video at once.
The sound is like some record is rattling. I checked the recordings and found no errors. When changing the oil, I checked the filter and there was no metal filings inside. The sound occurs when the engine starts running and emits more vibration. It does not appear at idle and higher speeds. I continue my search, I start breaking down the exhaust, first the cover plates, the exhaust drum and so on. I also check the exhaust seals, I had a problem that the exhaust bolts were lost, they fell out of the vibration. What I still think about is that in the exhaust, one of the plates of the continuation was released by the welding, which can still move cold but gets stuck warm due to the thermal expansion.
Laszlo