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Upsample the slews in Soft Vacuum

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Now the oversampled versions sound similar to the non-oversampled
version.
This commit is contained in:
Robbert van der Helm 2023-04-05 19:52:41 +02:00
parent f922e668b7
commit ad5f0ce72a
2 changed files with 37 additions and 7 deletions
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1
plugins/aw_soft_vacuum/src/hard_vacuum.rs
View file

@ -55,6 +55,7 @@ impl HardVacuum {
/// multichannel audio.
///
/// Output scaling and dry/wet mixing should be done externally.
#[allow(unused)]
pub fn process(&mut self, input: f32, params: &Params) -> f32 {
let slew = self.compute_slew(input);

43
plugins/aw_soft_vacuum/src/lib.rs
View file

@ -44,6 +44,10 @@ struct SoftVacuum {
hard_vacuum_processors: Vec<hard_vacuum::HardVacuum>,
/// Oversampling for each channel.
oversamplers: Vec<oversampling::Lanczos3Oversampler>,
/// Oversampling for each channel's slew control signal. This is upsampled separately to make
/// the oversampled algorithm sound similar to the regular, non oversampled version as the slews
/// will necessarily be lower in the oversampled version.
slew_oversamplers: Vec<oversampling::Lanczos3Oversampler>,
/// Scratch buffers that the smoothed parameters can be rendered to. Allocated on the heap
/// because Windows uses tiny stack sizes which may eventually cause problems in some hosts.
@ -207,6 +211,7 @@ impl Default for SoftVacuum {
hard_vacuum_processors: Vec::new(),
oversamplers: Vec::new(),
slew_oversamplers: Vec::new(),
scratch_buffers: Box::default(),
}
@ -257,6 +262,9 @@ impl Plugin for SoftVacuum {
self.oversamplers.resize_with(num_channels, || {
oversampling::Lanczos3Oversampler::new(MAX_BLOCK_SIZE, MAX_OVERSAMPLING_FACTOR)
});
self.slew_oversamplers.resize_with(num_channels, || {
oversampling::Lanczos3Oversampler::new(MAX_BLOCK_SIZE, MAX_OVERSAMPLING_FACTOR)
});
if let Some(oversampler) = self.oversamplers.first() {
context.set_latency_samples(
@ -275,6 +283,9 @@ impl Plugin for SoftVacuum {
for oversampler in &mut self.oversamplers {
oversampler.reset();
}
for oversampler in &mut self.slew_oversamplers {
oversampler.reset();
}
}
fn process(
@ -325,15 +336,32 @@ impl Plugin for SoftVacuum {
.smoothed
.next_block(dry_wet_ratio, upsampled_block_len);
for (block_channel, (oversampler, hard_vacuum)) in block.into_iter().zip(
self.oversamplers
.iter_mut()
.zip(self.hard_vacuum_processors.iter_mut()),
) {
for (block_channel, ((oversampler, slew_oversampler), hard_vacuum)) in
block.into_iter().zip(
self.oversamplers
.iter_mut()
.zip(self.slew_oversamplers.iter_mut())
.zip(self.hard_vacuum_processors.iter_mut()),
)
{
// The slew signal is computed and oversampled first. This is then used as a control
// signal in the oversampled version of the algorithm so it sounds more similar to
// the non-oversampled version. Otherwise the slews are necessarily going to be much
// lower.
let mut slews = [0.0f32; MAX_BLOCK_SIZE];
for (sample, slew) in block_channel.iter().zip(slews.iter_mut()) {
*slew = hard_vacuum.compute_slew(*sample);
}
let upsampled_slews =
slew_oversampler.upsample_only(&mut slews, oversampling_factor);
oversampler.process(block_channel, oversampling_factor, |upsampled| {
assert!(upsampled.len() == upsampled_block_len);
for (sample_idx, sample) in upsampled.iter_mut().enumerate() {
for (sample_idx, (sample, slew)) in
upsampled.iter_mut().zip(upsampled_slews).enumerate()
{
// SAFETY: We already made sure that the blocks are equal in size. We could
// zip iterators instead but with six iterators that's already a bit
// too much without a first class way to zip more than two iterators
@ -346,7 +374,8 @@ impl Plugin for SoftVacuum {
let output_gain = unsafe { *output_gain.get_unchecked(sample_idx) };
let dry_wet_ratio = unsafe { *dry_wet_ratio.get_unchecked(sample_idx) };
let distorted = hard_vacuum.process(*sample, &hard_vacuum_params);
let distorted =
hard_vacuum.process_with_slew(*sample, &hard_vacuum_params, *slew);
*sample = (distorted * output_gain * dry_wet_ratio)
+ (*sample * (1.0 - dry_wet_ratio));
}