True Peak Computation

[joelmacx]

Description

The plugins often hit resource and performance walls when hosted in DAWs due to the number of channels they have to process. The two processors that consume the majority of plugin processing time are the rendering processor and the loudness measurement processor. Of the loudness measurements, the true peak computation occupies nearly all the computation time. This PR replaces the existing implementation (interpolate -> LPF) with a polyphase filter implementation.

This will improve plugin performance in hosts, resulting in less errors from the hosts and greater plugin stability.

Changes

1. Add a TruePeak type for calculating the true peak of a buffer.
2. Update MeasureEBU128 to use this new type.

Validation and Acceptance Criteria

• Existing unit test coverage remains passing.
• Tested playback in DAW and confirmed realistic values were being calculated.

Wall Clock Measurements

These measurements were taken while computing loudness on 30s worth of samples.

Old measurement computation time
Layout | Time (ms)
2.0.0 85
3.1.2 241
7.1.4 492
9.1.6 661

New measurement computation time
Layout | Time (ms)
2.0.0 9
3.1.2 26
7.1.4 53
9.1.6 74

[joelmacx]

These debug logs were adding a lot of unhelpful noise so I'm just removing them (which I believe is permissible under this license?)

[BrandenAvalonCx]

Yeah, this is fine

[BrandenAvalonCx]

I'm surprised the performance is so bad here, but as long as the tests are passing the values should be fine. I don't see any issues here.