[v2][macOS] No sound is output to audio driver, nor is any output via fluid_synth_process()

[Birch-san]

Regression. Both these use-cases work fine in v1.

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I built master like so:

# get brew dependencies from v1 FluidSynth
brew install fluidsynth --with-libsndfile pkg-config

# now let's build v2
git clone git@github.com:FluidSynth/fluidsynth.git
# very recent commit in master
git checkout 29d194
mkdir -p build
cd build
cmake -Denable-framework=OFF -Denable-portaudio=OFF -Denable-libsndfile=ON ..
make

This output a binary to build/src/fluidsynth.

I attempted to play a MIDI file through a soundfont:

build/src/fluidsynth SGM-V2.01.sf2 mario.mid

No audio came out of my system. I assume this means nothing is output to CoreAudio.

This is definitely a regression, because next I tried brew fluidsynth v1, from my path:

fluidsynth SGM-V2.01.sf2 mario.mid

It played audio, as expected.

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I don't think this is a CoreAudio problem. The same thing happens when I invoke fluid_synth_process(…) directly to render MIDI into a block of audio samples.

I linked my VST against build/src/libfluidsynth.2.0.0.dylib, updated the includes and source, and now no sound is heard when my audio plugin outputs audio to the plugin host via fluid_synth_process().

Is there anything that it would be useful for me to do to debug this for you?

[Birch-san]

I've now pulled the latest master commit a55e7e8, rebuilt and no improvement.

One more observation: build/src/fluidsynth SGM-V2.01.sf2 mario.mid actually aborts audio playback (with no error given) after half a second.

Additionally: I've tried running my VST with fluid_settings_setstr(settings, "synth.verbose", "yes");, and no interesting messages are output by fluidsynth.

[derselbst]

Indeed, seems like I've broken my local setup... should be fixed in a second.

fluid_settings_setstr(settings, "synth.verbose", "yes");, and no interesting messages are output by fluidsynth.

synth.verbose is an int setting, you must use fluid_settings_setint(). And make sure to check the return values of those functions.

[Birch-san]

Thanks! Working now.

In case you're interested, these are the code changes I needed to make to upgrade from FluidSynth 1 -> 2:

Birch-san/juicysfplugin@b9eb853

I'll emphasise that 2.0.0.beta1 didn't expose enough public API, so I was reliant on the solution to this issue (now in master): #391

[derselbst]

Ok, thanks for the feedback!