[AudioFilterSW] Fix audio cutting out due to numerical errors #102210
+5
−5
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This aims to fix a long-standing audio issue which someone at my local user group brought up.
When interpolating the cutoff frequency of the AudioEffectFilterHighPass towards 1.0, at a certain point the audio becomes unstable until it suddenly stops working and clips (+- 1.0 on both channels).
After investigation I found out that this problem (probably) occurs due to numerical cancelation/inprecision when calculation the coefficients of the biquad filter.
For some reason, the coefficients were of type float while the rest of the code used double.
After increasing the precision, the issue was gone for me. There might be a better solution, but for now this is probably the quickest and safest way to fix it.
Other filter effects which use AudioFilterSW under the hood might benefit from this too.