jthedering
90ee2b0aa9
Added: Filter type "IIR", which allows to specify a user-defined IIR filter of arbitrary order with custom coefficients. Improved: For playback devices, the APO is now installed both as GFX (post-mix) and LFX (pre-mix) APO. Normally the filtering happens in GFX, but the command "Stage" allows to select LFX to apply effects based on the number of input channels. Added: Expression language. The commands "If", "ElseIf", "Else", "EndIf", "Eval" and inline expressions allow to change the filter behaviour based on runtime conditions. Added: Command "Copy", which copies audio data between channels. Added: Command "Delay", which delays the audio on the currently selected channels. Improved: Configuration files are now locked exclusively for writing while reading them. Improved: There is now a transition (10 ms) from old to new configuration after loading. Improved: Substantial internal restructuring to improve extensibility and maintainability. Filtering commands now work exactly in the order they were specified. Fixed: When the microphone input was in stereo but the application requested a mono stream, the audio was heavily distorted. Fixed: The sine sweep generated by the Benchmark application had floating-point precision issues leading to severe artifacts when certain filters were applied.
19 lines
524 B
Plaintext
19 lines
524 B
Plaintext
# This shows how to create a lowpass biquad filter using the IIR filter type
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# The result should be equivalent to the command
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# Filter: ON LP Fc 3000 Hz
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Do: `freq = 3000`
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Do: `Q = 1/sqrt(2)`
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Do: `omega = 2 * pi * freq / sampleRate`
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Do: `sn = sin(omega)`
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Do: `cs = cos(omega)`
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Do: `alpha = sin(omega) / (2 * Q)`
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Do: `a0 = (1 - cs) / 2`
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Do: `a1 = 1 - cs`
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Do: `a2 = (1 - cs) / 2`
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Do: `b0 = 1 + alpha`
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Do: `b1 = -2 * cs`
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Do: `b2 = 1 - alpha`
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Filter: ON IIR Order 2 Coefficients `a0` `a1` `a2` `b0` `b1` `b2`
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