zerberus: frequent clicking noises when playing samples

• Apr 24, 2018 - 14:53
Reported version
S2 - Critical

Steps to reproduce:
1. Download the attached test file.
2. Copy the .sfz file and sample folder to MuseScore's SoundFont directory.
3. Load the test .mscz file into MuseScore.
4. Go to "View" -> "Synthesizer" and click "Load from Score" to load the samples.
5. Play the project. WARNING! The third test can get quite loud, so be ready to turn down the volume.

Items of note within the test:
Test #1: You will usually hear clicks at the end of the samples. Here, the same sample ("hit_1.ogg") is being played twice at the same time. Actually, one of the sample instances is supposed to be delayed by a quarter of a second, but Zerberus doesn't currently support the "delay" opcode.
Test #7: You will hear clicks near the beginning of both notes. These clicks are not audible when playing the samples ("roll_dim_short_L.ogg" and "roll_dim_short_R.ogg") in Audacity or when loading the SFZ file in Plogue sforzando. There are flaws in the waveform that lead to the clicks, but why are the clicks so loud in Zerberus? It's almost like really high frequencies are being amplified somehow.
Test #8: You will usually hear clicks near the end of some of the samples, but what's weird is that the clicks don't show up consistently. For example, if you re-load the sounds (remove and then re-add the SFZ instrument), then jump straight to test #8 and play it, there's a good chance you won't hear any clicks on release. However, if you reload the sounds then play through the entire project, you'll probably hear the clicks at the end of the test #8 samples.

None of these samples exhibit clicks when played in Audacity or Plogue sforzando.

Attachment Size
Zerberus_test_01.zip 427.27 KB


There is no clicking noise in 2.1. It is definitely a regression in 2.2.1 and master. I'm pretty sure that the reason is my changes in caching buffer frames when fixing Bluetooth and MacOS no sound issues.

Severity S4 - Minor S2 - Critical

Windows 10:
2.2.1 official release installed on my laptop produces the clicking noise.
2.1 official release installed on my laptop doesn't produce the clicking noise.
2.1 tag built locally on my machine both release and debug produce the clicking noise.

Set priority to critical cause we cannot make a release without fixing this issue. It is a corruption of playback.