I am trying to use the following command with the latest ffmpeg build to remove silence from my .mp3 files:
ffmpeg -i SILENCE.mp3 -af silencedetect=n=-50dB:d=1 -y -ab 192k SILENCE_OUT.mp3
However, the following output is produced:
ffmpeg version N-66154-g1654ca7 Copyright (c) 2000-2014 the FFmpeg developers
built on Sep 5 2014 22:10:38 with gcc 4.8.3 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --
enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-lib
modplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrw
b --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinge
r --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --en
able-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis
--enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-
libx265 --enable-libxavs --enable-libxvid --enable-decklink --enable-zlib
libavutil 54. 7.100 / 54. 7.100
libavcodec 56. 1.100 / 56. 1.100
libavformat 56. 4.100 / 56. 4.100
libavdevice 56. 0.100 / 56. 0.100
libavfilter 5. 1.100 / 5. 1.100
libswscale 3. 0.100 / 3. 0.100
libswresample 1. 1.100 / 1. 1.100
libpostproc 53. 0.100 / 53. 0.100
Input #0, mp3, from 'SILENCE.mp3':
Metadata:
title : Snowblind (Featuring Tasha Baxter)
artist : Au5
album : Snowblind (Featuring Tasha Baxter)
genre : Electronica
performer : Au5
track : 1/1
date : 2014
album_artist : Au5,Tasha Baxter
major_brand : mp42
minor_version : 0
compatible_brands: isommp42
encoder : Lavf55.42.100
Duration: 00:05:50.80, start: 0.025057, bitrate: 192 kb/s
Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 192 kb/s
Output #0, mp3, to 'SILENCE_OUT.mp3':
Metadata:
TIT2 : Snowblind (Featuring Tasha Baxter)
TPE1 : Au5
TALB : Snowblind (Featuring Tasha Baxter)
TCON : Electronica
TPE3 : Au5
TRCK : 1/1
TDRL : 2014
TPE2 : Au5,Tasha Baxter
major_brand : mp42
minor_version : 0
compatible_brands: isommp42
TSSE : Lavf56.4.100
Stream #0:0: Audio: mp3 (libmp3lame), 44100 Hz, stereo, s16p, 192 kb/s
Metadata:
encoder : Lavc56.1.100 libmp3lame
Stream mapping:
Stream #0:0 -> #0:0 (mp3 (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
[silencedetect @ 0000000004398f40] silence_start: -0.00628118
[silencedetect @ 0000000004398f40] silence_end: 3.21413 | silence_duration: 3.22
041
[silencedetect @ 0000000004398f40] silence_start: 343.844
[libmp3lame @ 00000000043b2940] Trying to remove 1152 samples, but the queue is
empty
size= 8223kB time=00:05:50.79 bitrate= 192.0kbits/s
video:0kB audio:8222kB subtitle:0kB other streams:0kB global headers:0kB muxing
overhead: 0.011485%
The generated audio file however still has the original length without any silence removed. See the following images:
Any help is appreciated!
EDIT: Alright, silence detect is only DETECTING the silence. Not removing it. I will try to post a solution for this.
Use the silenceremove
filter. This removes silence from the audio track only - it will leave the video unedited, i.e., things will go out of sync
Its arguments are a little cryptic.
An example
ffmpeg -i input.mp3 -af silenceremove=1:0:-50dB output.mp3
This removes silence
1
) 0
)-50dB
).Documentation: FFMPEG silence remove filter
Also anyone looking to find the right value to classify silence as may wish to look into normalising their input audio volume to 0dB
first, to do this in ffmpeg see this answer.
Edit
As pointed out by @mems, to detect whether your version of ffmpeg has the filter run
ffmpeg -hide_banner -filters | grep silenceremove
if you have the filter it'll output something like
silenceremove A->A Remove silence