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sffilters − applies a number of filters to a soundfile. |
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sffilters [-t n][-f n][-w n][-N n][-o output][-b][-info] inputSoundfile |
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sffilters applies a variety of filters to a soundfile. |
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-t |
0 Butterworth low-pass, specify cutoff frequency. |
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1 Butterworth high-pass, specify cutoff frequency. |
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-f c |
Cutoff frequency or center frequency, depending on type of filter chosen. |
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-w b |
Bandwidth for bandpass and band-reject filters. |
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-N n |
Number of taps for the N-order FIR filter. |
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-o outputSoundfile |
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Write the output to the outputSoundfile . |
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-b |
Boost sound to maximum after filtering. -info Print the filter equations to the screen. |
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Filters 0-3 |
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Butterworth filters: y[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2] - b1 * y[n-1] - b2 * y[n-2] |
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Filter 4 |
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2nd order Infinite Impulse Response (IIR) filter: y[n] = a0 * x[n] - b1 * y[n-1] - b2 * y[n-2] |
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Filter 5 |
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2nd order Finite Impulse Response (FIR) filter: y[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2] |
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Filter 6 |
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N-order FIR filter (lowpass): y[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2] + ... + aN * x[n-N] |
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Filter 7 |
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Two-pole IIR filter: y[n] = G * (x[n] - R * x[n-2]) + b1 * y[n-1] + b2 * y[n-2] |
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sffilters -t 0 -f 1000 -o output.wav input.aiff |
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Apply a Butterworth lowpass filter (-t 0) with a cutoff frequency of 1000 Hertz (-f 1000) to the file input.aiff and place the output in the file output.wav (-o output.wav). |
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sffilters -t 6 -N 15 -f 800 -o output.aiff input.wav |
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Apply an N-order FIR filter (-t 6) with 15 taps (-N 15) and a cutoff frequency of 800 Hertz (-f 800) to the input file input.wav and place the output in the file output.aiff . |
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This program will only work with WAVE, AIFF, AIFC, and the old NeXT/Sun "snd" format soundfiles, that are 16-bit PCM encoded, with 1 or 2 channels. |
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Arun Chandra <arunc@evergreen.edu> sffilters is free software. |