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Add a DC filter

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This commit is contained in:
Robbert van der Helm 2022-07-14 15:39:04 +02:00
parent 12aa8544cd
commit 46faaaf1ac
1 changed files with 17 additions and 0 deletions
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17
plugins/spectral_compressor/src/lib.rs
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@ -84,6 +84,10 @@ struct SpectralCompressorParams {
/// applying the output gain. In other words, the dry signal is not gained in any way.
#[id = "dry_wet"]
dry_wet_ratio: FloatParam,
/// Sets the 0-20 Hz bin to 0 since this won't have a lot of semantic meaning anymore after this
/// plugin and it will thus just eat up headroom.
#[id = "dc_filter"]
dc_filter: BoolParam,
}
impl Default for SpectralCompressor {
@ -134,6 +138,7 @@ impl Default for SpectralCompressorParams {
.with_unit("%")
.with_value_to_string(formatters::v2s_f32_percentage(0))
.with_string_to_value(formatters::s2v_f32_percentage()),
dc_filter: BoolParam::new("DC Filter", true),
}
}
}
@ -224,6 +229,8 @@ impl Plugin for SpectralCompressor {
// FIXME: Use the parameter
// [self.params.window_size_order.value as usize - MIN_WINDOW_ORDER];
[DEFAULT_WINDOW_ORDER - MIN_WINDOW_ORDER];
let num_bins = self.complex_fft_buffer.len();
let sample_rate = context.transport().sample_rate;
// The overlap gain compensation is based on a squared Hann window, which will sum perfectly
// at four times overlap or higher. We'll apply a regular Hann window before the analysis
@ -258,6 +265,16 @@ impl Plugin for SpectralCompressor {
// TODO: Do the thing
// The DC and other low frequency bins doesn't contain much semantic meaning anymore
// after all of this, so it only ends up consuming headroom.
if self.params.dc_filter.value {
// The Hann window function spreads the DC signal out slightly, so we'll clear
// all 0-20 Hz bins for this.
let highest_dcish_bin_idx =
(20.0 / ((sample_rate / 2.0) / num_bins as f32)).floor() as usize;
self.complex_fft_buffer[..highest_dcish_bin_idx + 1].fill(Complex32::default());
}
// Inverse FFT back into the scratch buffer. This will be added to a ring buffer
// which gets written back to the host at a one block delay.
fft_plan