Start a recording that does not contain the delay
The following example shows how this filter can be used to start a recording that does not contain the delay at the start which usually occurs between pressing the record button and the start of the performance:
silenceremove=start_periods=1:start_duration=5:start_threshold=0.02
Trim all silence encountered from beginning to end where there is more than 1 second of silence in audio:
silenceremove=stop_periods=-1:stop_duration=1:stop_threshold=-90dB