[CentOS] Stripping silent periods from MP3s

Lamar Owen lowen at pari.edu
Mon Dec 13 16:26:12 UTC 2010


On Sunday, December 12, 2010 12:48:36 pm Keith Roberts wrote:
> Or are there any other programs that can be used to strip 
> silent periods from MP3's?

Please see the mp3splt and mp3join programs referenced by 
http://stream-recorder.com/forum/mp3-splitting-based-silence-detection-command-line-t5510.html

The most difficult thing you'll have to do is define what you mean by silence; even with 16-bit source material referenced to K14 (-14dBFS = 0dBr; good radio quality headroom) you have a low end limit at  -84.08dBr (16 bits * 6.02dB + 1.76dB gives 98.08dB of dynamic range; with -14dBFS as the 0 dB relative reference, that gives a minimum audio level (noise floor) of -84.08dBr).  Even with 24 bit audio you never reach absolute silence (- infinity dBr; at best, using a K20 reference (-20dBFS = 0dBr; cinematic headroom standard) you get to -126.46dBr; 146.46dB of dynamic range at 24 bits, which exceeds the human ear's dynamic range of 140dB). 

But the mp3splt tool allows you to tell it what you mean by silence; you set a dB threshold and set a time the signal must be below that threshold; then you re-join the split files and you have your silence-removed audio.

For more info on the 'K system' for digital audio to reference level setup, see Bob Katz's 'Mastering Audio' (has nothing to do with the common meaning of mastering, as in learning about audio; this book is about taking a mixed track and then mastering it for duplication) or his website, specifically the pages at:
http://www.digido.com/level-practices-part-2-includes-the-k-system.html



More information about the CentOS mailing list