Incorrect or silent instruments in some songs when restarting MIDI playback

[mrbumpy409]

FluidSynth version

FluidSynth PR #1516

Describe the bug

The AWE32 MIDI song The Bloodwar by Jess D. Skov-Nielsen is accompanied by a SoundFont to be loaded into bank 1. All instruments in the MIDI file should play bank 1 presets (GM on bank 0 is not used at all). When playing "The Bloodwar.mid" using FluidSynth's built-in MIDI player with "The Bloodwar.sf2" loaded into bank 1, some of the instruments incorrectly play using bank 0 instruments.

Expected behavior

All channels except for 10 (unused) should be playing presets on bank 1.

Steps to reproduce

1. Download and extract The Bloodwar.zip, which contains my 2.01/2.04 spec conversion of the original AWE32 SoundFont.
2. Load The Bloodwar.mid in FluidSynth:

   fluidsynth "The Bloodwar.mid"
   

3. In FluidSynth's console, stop playback, load The Bloodwar.sf2 into bank 1 and restart playback:

   player_stop
   load "The Bloodwar.sf2" 1 1
   player_start
   player_cont
   

About 16 seconds in, you should hear a choir chanting sound accompanied by staccato strings, and at around 34 seconds, a deep, growly voice says "Bloodwar!" several times. However in FluidSynth's MIDI player, neither the choir, strings, nor voice happens. Instead, the MIDI tracks responsible for those samples play on bank 0.

Additional context

The song and all of its samples do play correctly under the following circumstances:

1. FluidSynth's internal MIDI player with Bloodwar.sf2 loaded to bank 0.
2. The MIDI played by a separate MIDI player routed to FluidSynth with Bloodwar.sf2 loaded to bank 1 (tested using Sekaiju and Qsynth).

[derselbst]

Yeah, I can reproduce that. Can you confirm that it behaves correctly when passing the shell commands by using a config file with the -f flag?

[mrbumpy409]

Yeah, I can reproduce that. Can you confirm that it behaves correctly when passing the shell commands by using a config file with the -f flag?

Yes, I can confirm that the song plays correctly in this scenario.

[mrbumpy409]

Am I correct that using the -f flag causes the .fluidsynth config file to be ignored? FluidSynth appeared to not be loading my default GM SoundFont when I used the -f flag to load "The Bloodwar.sf2" into bank 1.

[derselbst]

Am I correct that using the -f flag causes the .fluidsynth config file to be ignored?

Correct, config files cannot be stacked. If the user config is found, the system-wide config will be ignored. If one is provided via -f, the user config (and consequently the system-wide config) will be ignored.

[mrbumpy409]

Looking at the MIDI file, I'm seeing the following on several tracks, all at the same timestamp:

1. CC0: select bank 1
2. Program change: select preset
3. CC0: select bank 0

The CC0 event at no.3 does not have a corresponding preset change, and so has no effect. However, when doing player_stop, loading the SoundFont to bank 1 and then player_start & player_cont, it would seem FluidSynth's player is seeing the no.3 CC0 event and thinking the preset should stay on bank 0.

So, while this is definitely a bug in FluidSynth's MIDI player, those dangling CC0 events are just asking for trouble. By removing them, the bug no longer manifests in FluidSynth. Here is the fixed MIDI file.

[mrbumpy409]

I ran into another similar issue that can be easily reproduced. It seems that when restarting the MIDI player, FluidSynth is sometimes not correctly processing all of the events at the very start of the MIDI file.

Steps to Reproduce

1. Download and extract this MIDI file.
2. Start playing the file in FluidSynth. You should hear a strings note and a choir note played simultaneously.
3. Restart the MIDI player via player_stop, player_start, player_cont.

Result: Silence. The string and choir note do not play.

📝 Note that this MIDI file was originally supposed to be triggering ambient sustained samples in a custom SoundFont, hence the discordant notes at the beginning.

[derselbst]

Thanks for the reproducer. A PR is ready.

[mrbumpy409]

I can confirm that the PR fixes the issues with the two MIDI files I posted.

[derselbst]

Thanks Chris!