| Jeff Abrahamson on 26 Jan 2006 18:06:34 -0000 |
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On Thu, Jan 26, 2006 at 12:23:40PM -0500, Doug Crompton wrote: > [25 lines, 185 words, 1219 characters] Top characters: ein_otla > > Ok... thanks for your help that worked fine.... > > wget, mpg321, sox infile -b -r 8000 outfile > > The final result was a 8k rate 8 bit file. It is voice only. This is to be > sent over a radio communications channel and the quality is fine except > for one thing. Either in the original encoding or rate change, or both, > the background or silence noise is to high to do what I want to do. > > The recording purposely has a no speaking period but the noise floor is to > high for my broadcast equipment to recognize it. I need to filter, remove > all sound below a certain level. I do not think low/high pass will work > but rather sensing a period of silence below a certain level and inserting > pure silence. Sox has a noise filtering mode but it requires knowing where > there is already silence and then doing a second pass. Since I want to do > this from the command line unattended I don't think this would work. Any > ideas? My first thought was to filter out everything over 15 KHz or so. If it's voice, that should do very nicely. Telephone is (or used to be) filter below 4 KHz or so and no one ever complained too much. If you make the silent periods *really* silent, listeners tend to think something's broken. If there's music or intentional background noise, you would hurt. In any case, let me know what you finally do and how, either individually or to the list. I'm curious how you finally solve this, both what works and what doesn't. -- Jeff Jeff Abrahamson <http://www.purple.com/jeff/> +1 215/837-2287 GPG fingerprint: 1A1A BA95 D082 A558 A276 63C6 16BF 8C4C 0D1D AE4B Attachment:
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