[FFmpeg-user] silenceremove use

Ted Park kumowoon1025 at gmail.com
Wed Feb 19 11:11:02 EET 2020

> Is there anyone who has experience with the silenceremove filter? I'm trying to remove long silences from recordings i made on my phone. The silences are actually a constant noise because of the microphone gain is set to 5.0x. (The playback meter in Audacity says the noise is around -48 to 42 dB). It is around 9 hours in duration. 1,1 GB large, signed 16 bit little endian mono 16 kHz wave file. Audacity says it's 32 bit float wave file though.

Hey there,
As you’ve noticed you pretty much need to know the basic “profile,” I guess, of the silence in your audio for best results. You could use the show volume filter with ffplay, 
% ffplay -f lavfi -i “amovie=$INPUT,showvolume"
To get a general idea of what the noise is like, and apply the options accordingly.
e.g. 	Use the levels of the silence/noise sections for the level options, setting -20db would cut out a lot more than noise, I think; see if there are short periods of noise, other than background noise, but still noise, and see how long those are to set a value for the duration options; also see if using peak and a window of 10 seconds makes sense (It might not, even if you set a more sensible value for the threshold, basically I think that would make it treat anything as silence if in a 10 second window it rises above the threshold even once)

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