filters = '
Normalize

Bringing to highest possible loudness without distortions
Fade
1Beginning    Duration [sec]
1End     Duration [sec]


Add a fade effect to the beginning, end, or both of the audio.
For fade-ins, this starts from the first sample and ramps the volume of the audio from 0 to full volume over Duration seconds.
For fade-outs, the volume will be ramped from full volume down to 0 starting at Duration seconds before the stop-time.
No Silence
1Beginning      1End Silence threshold [0 - 1]

Removes silence from the beginning or end of the audio. Silence is anything below a specified threshold.
Threshold is used to indicate what sample value you should treat as silence. For digital audio, a value of 0 may be fine but for audio recorded from analog, you may wish to increase the value to account for background noise.
Bass
 ratio  Frequency [Hz]


Boost or cut the bass (lower) frequencies of the audio using a two-pole shelving filter with a response similar to that of a standard hi-fi’s (Baxandall) tone-controls.
Frequency sets the filter’s central frequency and so can be used to extend or reduce the frequency range to be boosted or cut. The default value is 100 Hz.
Treble
 ratio  Frequency [Hz]


Boost or cut the treble (upper) frequencies of the audio using a two-pole shelving filter with a response similar to that of a standard hi-fi’s (Baxandall) tone-controls.
Frequency sets the filter’s central frequency and so can be used to extend or reduce the frequency range to be boosted or cut. The default value is 3 kHz.
Reverse

Reverse the audio completely.
Speed Factor
 Ratio

Adjust the audio speed (pitch and tempo together).
Ratio is either the ratio of the new speed to the old speed: greater than 1 speeds up, less than 1 slows down.
Pad
1Beginning    Duration [sec]
1End    Duration [sec]


Pad the audio with silence, at the beginning or end of the audio.
Band Reject
 Frequency [Hz] Dispersion [Hz]

Band-reject filter with central frequency (in Hz) frequency, and (3dB-point) band- width Dispersion in Hz.
Chorus
 Delay [msec] Decay [Hz] Speed [Hz] Depth [msec]

Add a chorus effect to the audio.
Each four-tuple delay/decay/speed/depth gives the delay in milliseconds and the decay with a modulation speed in Hz using depth in milliseconds.
Echo
 Delay [msec] Decay [Hz]

Add echoing to the audio. Each delay decay pair gives the delay in milliseconds and the decay of that echo.
Reverb
 Time [msec] Delays [msec]

Add reverberation to the audio.
Each delay is given in milliseconds and its feedback is depending on the reverb-time in milliseconds. Each delay should be in the range of half to quarter of reverb-time to get a realistic reverberation.
Flanger
 Delay [msec, 0 - 10]  Depth [msec, 0 - 10]
 Regeneration [%, -95 - 95]  Width [%, 0 - 100]
 Speed [Hz, 0.1 - 10] Shape   sin     triangle
 Phase  linear    quadratic

Apply a flanging effect to the audio.
Delay: base delay in milliseconds, depth: added swept delay in milliseconds, regeneration: percentage regeneration (delayed signal feedback), width: percentage of delayed signal mixed with original, speed: sweeps per second (Hz), shape: swept wave shape, phase: swept wave percentage phase-shift for multi-channel (e.g. stereo) flange; 0 = 100 = same phase on each channel, interpretation digital delay-line interpolation.
Highpass
 Frequency [Hz]
Pole -1 single   -2 double


Apply a high-pass filter with 3dB point frequency.
The filter can be either single-pole or double-pole.
Lowpass
 Frequency [Hz]
Pole -1 single   -2 double


Apply a low-pass filter with 3dB point frequency.
The filter can be either single-pole or double-pole.
Phaser
 Delay [msec] Decay [Hz] Speed [Hz]

Add a phasing effect to the audio.
Delay in milliseconds and the decay with a modulation speed in Hz. The decay should be less than 0.5 to avoid feedback.
Stretch Factor
 Ratio

Time stretch the audio by the given factor.
Changes duration without affecting the pitch. Ratio of stretching: >1 lengthen, <1 shorten duration.
Tremolo
 Speed [Hz] Depth [%]

Apply a tremolo effect to the audio.
The tremolo frequency in Hz is given by speed, and the depth as a percentage by depth (default 40).
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