SoX recording audio and trimming silence

sox -t alsa default ./recording.flac silence 1 0.1 5% 1 1.0 5%
Records audio from your mic in FLAC (Free Lossless Audio Codec) format, starts only after it detects at least 0.1 seconds of noise and stops after 1 second of silence. You can adjust the percent values (sensitivity) to best fit your microphone and voice (0.1% if you have a great quality mic, higher if you don't, 0% does not trim anything). Useful for speech recognition in conjunction with my previous command titled 'Google voice recognition "API"' (http://www.commandlinefu.com/commands/view/8043/google-voice-recognition-api).

1
By: sairon
2011-03-08 14:36:39

These Might Interest You

  • Very useful for recording radio scanner for instance as the resulting audio file contains only audio signal that exceeds -45dB and the file name tells you when the recording was done. Why waste time listening silence? ;) Show Sample Output


    0
    rec -r 44100 -p | sox -p "audio_name-$(date '+%Y-%m-%d').ogg" silence -l 1 00:00:00.5 -45d -1 00:00:00.5 -45d
    FuFighter · 2011-02-17 08:55:01 0
  • It find out the mic recording level at the moment of run the command and if a noise level is higher it starts to record an mp3 file. The resulting file will have only the sounds not the silences.


    2
    arecord -q -f cd -d 1 recvol.wav;sox recvol.wav -n stat 2>&1|grep RMS|grep amplitude|cut -d"." -f2|cut -c 1-2>recvol;echo $((`cat recvol`+1))>recvol;rec -t wav - silence 1 0.1 `cat recvol` -1 1.0 `cat recvol`%|lame -s 44.1 -a -v - >record.mp3
    geaplanet · 2014-02-27 23:23:55 0
  • The option -an disables audio recording, -f forces the use of video4linux for the input, -s sets the video to the size 320x240, -b sets the recording bitrate, -r sets the frame rate to 15fps, -i gives the input device, -vcodec sets the output format. Press Q to stop recording or you can specify the recording time with the -t option like -t 00:1:30


    3
    ffmpeg -an -f video4linux -s 320x240 -b 800k -r 15 -i /dev/v4l/video0 -vcodec mpeg4 myvideo.avi
    dcabanis · 2009-06-19 17:41:43 2
  • There are some pretty good live performances on late night TV. With Mythtv I record David Letterman, Jimmy Fallon, and Conan nightly all in HD from over the air broadcasts. If I find a live performance I like I copy it to my Rockboxed iPod using this command. The Rockbox firmware knows how to downmix 5.1 audio. The command above extracts the audio from the video starting at 58 minutes and 15 seconds. It ends at the end of the file since this was the last performance of the recording. The command creates an ac3 file. I copy the ac3 file to my Rockbox iPod and rock on.


    3
    ffmpeg -ss 0:58:15 -i DavidLettermanBlackCrowes.mpg -acodec copy DavidLettermanBlackCrowes.ac3
    PLA · 2009-09-14 00:08:36 0

What Others Think

Hello, this works perfectly for actually recording the audio, although the recorded flac does not end up being readable by the Google Voice recognition API. I did have to change "alsa" with "waveaudio". Any ideas would be much appreciated. I tried going through the SOX documentation and trying various things, but nothing worked. Thank you.
aml25 · 325 weeks ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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