For me signal not Stable , see screen shot below .
For you If signal good and stable then record one minute and report the bug for lav filter at github press new issue and explain your problem and then upload the video you recorded https://github.com/Nevcairiel/LAVFilters/issues
For you If signal good and stable then record one minute and report the bug for lav filter at github press new issue and explain your problem and then upload the video you recorded https://github.com/Nevcairiel/LAVFilters/issues