Re: [fluid-dev] Problem in fluidsynth (Ubuntu 11.10) still in Ubuntu 12.04

[Aere Greenway]

David:

I read the link on the SRU process, but am unsure of how to proceed with it, or whether I am even able to do so, not being a developer.  

I presume it hasn't been tested in the current Ubuntu 12.04 development release, and I am not in a position to post the fix for testing.  

I did verify that the PPA fix you made available for the Ubuntu 11.10 release fixes the problem when installed in 12.04.  I did this by changing the version designation of your PPA fix to the following:

libfluidsynth1_1.1.5-3ubuntu1~diwicppa_i386.deb

(it was formerly libfluidsynth1_1.1.5-1ubuntu1~diwicppa_i386.deb)

I re-built that modified-version-# Debian package, and was able to install it in 12.04 using gdebi.  

After doing so, I tested it in four of the machines in my test-bed - especially the  low-speed / low-memory machines (where the problem is brutally apparent), and the fix worked.  

Here is my description of the problem, to the extent of my understanding of it:

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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 unnecessary 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 it 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 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.  

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David, I have modified my automated install process for my MIDI training courseware to install my re-packaging of your PPA fix.  This gets me beyond the obvious problem for users trying to use the courseware, and when a new version of Qsynth (FluidSynth) is actually released, it should replace my re-packaged PPA (because of a higher version designation).  

I am hoping that somehow this fix can be put into 12.04, which is supposed to be supported for 3 years (a very long time).  

I tried to create a bug report on it in Ubuntu 12.04, but have not found a way to do it, since nothing crashes.  

If I can help by creating such a bug report, please let me know how to go about doing it, and I will do so.  

P.S. - Dr. Leo (also on the e-mail list) tried playing a standard MIDI file of one of the sequences demonstrating the problem (on fluidsynth he built on Windows), and it actually crashed.  This makes me wonder if the latest (or a later) version still fixes the problem, or if some new problem has reared its ugly head.  I would be happy to send you the MIDI file for your testing pleasure.  


Sincerely,
Aere

On Wed, 2012-05-02 at 15:47 +0200, David Henningsson wrote:
> On 04/28/2012 06:40 AM, Aere Greenway wrote:
> > All:
> >
> > Months ago, I discovered a problem with fluidsynth where voices for new
> > notes would fail to play because (my guess) older notes which had faded
> > to inaudible status were still playing.
> >
> > I worked with David Henningson on this problem, and he made a fix for it
> > available (in a PPA).
> >
> > This fixed the problem in Ubuntu 11.10, and I assumed it would be fixed
> > in the next release of Ubuntu (12.04).
> >
> > Unfortunately, the problem (or a similar, new problem) is in the version
> > of fluidsynth in Ubuntu 12.04.
>
> The bug is still present in Ubuntu 12.04.
>
> This mainly due to lack of time/priority/thought from my part.
>
> There has not been a release of FluidSynth lately, so there is no 
> upstream release that could have flown the "natural" way through Debian 
> to Ubuntu.
>
> And, nobody has tried to backport the actual commit (as a bug fix) to 
> Debian or Ubuntu.
>
> For Ubuntu 12.04, this fix should be SRUable, if somebody just sits down 
> and does the paperwork: https://wiki.ubuntu.com/StableReleaseUpdates
>
> I guess we could also release a version 1.1.6 of FluidSynth with the 
> current tree in it, if we like.
>
> // David

-- 

Sincerely,
Aere