Burst of noise when playing MIDI after loading sf3 for the first time on Chromium

[daxiangpanda]

After loading the SF3 soundfont with SpessaSynth, there is noticeable noise at the beginning of the MIDI when it is played for the first time. If you click to replay the MIDI, the noise disappears. Do you have any suggestions to resolve this issue?

[spessasus]

It's probably the chromium bug. There's not much I can do about it.

Try playing the MIDI in Firefox and it shouldn't happen.

[daxiangpanda]

Is this bug related to audioContext.audioWorklet.addModule?

[spessasus]

Is this bug related to audioContext.audioWorklet.addModule?

No, not really. It's the way Chromium renders audio.

You see, when Spessasynth loads a MIDI, it preloads all the sample's used in it for smooth playback. Sf3 uses compressed samples which, as you might guess, take time to decompress.

And that's fine. It stalls the audio thread for a little while before starting the playback, which is fine on Firefox.

But not on Chromium. When it stalls chromium's audio thread, it then tried to "catch up" by trying to render all lost audio frames in a split second! This is what you perceive as crackling.

I hope this clears things up.

[spessasus]

Hi, here's the link to chromium bug tracker regarding this bug:

https://issues.chromium.org/issues/367304685

[spessasus]

I'll keep this issue open until (hopefully) the Chromium bug is fixed.

[henrikvilhelmberglund]

I had a similar issue caused by not calling context.resume() on user input. In my case I have a playable keyboard instrument, on load it didn't make any sound, only when changing instruments the context would automatically resume and play all of the input sounds at once. Adding context.resume() in the event handlers (before trying to play notes) fixed the issue.

It sounds a bit weird though that SpessaSynth plays back the MIDI at the same time as preloading, shouldn't this be two steps? Are there any tips for implementing this? (actually load the soundfont before attempting playback)