The parameters (roomsize, level, etc.) of the reverb effects unit are initialized at the very end of `new_fluid_synth()` with `fluid_synth_set_reverb_full_LOCAL()`.
This however only adds an update-event to the `rvoice_mixer` queue.
The call to `fluid_synth_process_event_queue()` in `new_fluid_synth()` should make sure, that this event is dispatched and triggers the actual update.
However, the event is not dispatched immediately, because the rvoice event queue has not been committed yet, that is, a call to `fluid_rvoice_eventhandler_flush()` is missing.
So, although a reverb param initialization event has been queued, the reverb params still are garbage initialized (on Windows to some `-6.2774385622041925e+66`).
The next call to through the synth's public API will flush the queue and finally dispatch the update event, but when will it happen?
1. If the soundfont is specified as command-line argument, this call will happen before the audio driver starts rendering.
2. If the soundfont is loaded via shell command `load`, the audio driver will first start rendering audio, after updating the reverb.
Case 1. is trivial, everything works as it should.
Case 2. is interesting. Since the synth already started rendering audio by using that uninitialized reverb unit, the reverb engine's internal buffer is completely filled up with noise. Before outputting that signal to sound card, the sound is clipped to `1.0f`. That's the click we hear at the beginning. And because the reverb is so loud, the rendered audio signal stays 1.0f for quite a long time (...or always, can't tell).
Why is it not reproducible on Linux? Because GCC and Clang (AFAIK) leave all values uninitialized after allocating memory. And because malloc() often return zero-initialized memory, the reverb params seem to be nicely zero-initialized. MSVC however, always initializes memory with garbage, which is why we "hear" this resonance disaster.
Solution: Just update the reverb params via public API, which implicitly calls `fluid_rvoice_eventhandler_flush()`.
Fixes#563.
This document explains what sostenuto pedal is compared to sustain pedal. It is intended for a musician playing live. It gives information about specifications and implementation in fluidsynth.
Fixes a use-after-free when the MIDI player is deleted before the audio
driver, because the synthesis thread is still actively making callbacks
on the sample timer, which is deleted by the player though.
Enabling the option supresses the default welcome message and
some other text output that normally gets printed to stdout.
It also slightly changes the way the welcome message and argument
errors are handled: in case of an argument error, the welcome message
is never printed.
Previously, sample timers were deleted in fluid_player_stop() which caused a use-after-free when at the same time the sample timers were advanced by the synthesizer thread. This was incorrectly addressed in 5d3f727547 . Deleting sample timers is now done in delete_fluid_player(). A broken application could still crash if it does not respect the order of object creation though. At least now, this issue is properly documented.
In an out of memory situation, fluid_synth_t::voice and fluid_synth_t::channel may not be fully initialized, causing a NULL dereference and heap corruption in delete_fluid_synth().
