When playing a complex MIDI file, qsynth fails to play many new notes

[Aere Greenway]

When you play a MIDI file (using Qsynth) which has a lot of parts - especially piano parts (which have many simultaneous notes, and use the sustain pedal a lot), Qsynth gets into a bad state where new notes are either not played, or play for less than a half-second (and go silent).

This is especially apparent on low speed machines, where it is necessary to limit Qsynth's polyphony parameter to 64 or 48 to avoid excessive processor overhead.

Once Qsynth gets into this bad state, it will fail to play (with reasonable quality) even simple MIDI files. The only way to get it out of the 'bad state' is to restart the Qsynth 'engine' (or Qsynth itself).

The Qsynth (FluidSynth) developers posted a fix for this problem (in a PPA) for Ubuntu 11.10 (where the problem was first observed), and the PPA fixed the problem in Ubuntu 11.10.

I have re-packaged that PPA-version of libfluidsynth1, changing its version number so it can be installed in Ubuntu 12.04, and have tested it successfully in that (current LTS) release.

The original fix, posted as a PPA, was actually their main (trunk) version of libfluidsynth1 (at the time of the bug's discovery - they had already noticed the problem, and fixed it). For some reason, the new version of libfluidsynth1 was not committed for release into Ubuntu 12.04, so the bug in release 11.10 remains in 12.04.

The package with the bug is actually libfluidsynth1, which is used by fluidsynth, qsynth, and fluidsynth-dssi. The version of libfluidsynth having the problem is: 1.1.5-2

[Aere Greenway (aere)]

The version in the of the PPA fix was "1.1.5-1ubuntu1-diwicppa"

The PPA (for Ubuntu 11.10 was:

ppa:diwic/fluidsynth-test

This PPA can be used in Ubuntu 11.10, but can't be used in 12.04 because it has a version designation prior to what is in 12.04.

If you rebuild the ppa package with a package version/name of "libfluidsynth1_1.1.5-3ubuntu1~diwicppa_i386.deb", it can be used in Ubuntu 12.04, and I have tested that the fix works properly.