$ ffmpeg -h filter=nlmeans
Filter nlmeans
  Non-local means denoiser.
    slice threading supported
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
nlmeans AVOptions:
  s                 <double>     ..FV.... denoising strength (from 1 to 30) (default 1)
  p                 <int>        ..FV.... patch size (from 0 to 99) (default 7)
  pc                <int>        ..FV.... patch size for chroma planes (from 0 to 99) (default 0)
  r                 <int>        ..FV.... research window (from 0 to 99) (default 15)
  rc                <int>        ..FV.... research window for chroma planes (from 0 to 99) (default 0)

This filter has support for timeline through the 'enable' option.