[fluid-dev] Re: lost connection to Jack server (svn Rev 243, over the weekend)

[josh]

Hello Jimmy,

Quoting jimmy <address@hidden>:
> Hi Josh,
>
> I tried again, same midi file at   
> "http://mmacdonald.com/midi/XG/Conquistador 3K MM.MID".  Note that   
> this is a fairly busy, quick tempo/pace.
>
> As I type this, I use the mouse to drag the scroll bar in a GUI text  
>  editor, with the midi song playing in the background, I definitely   
> hear the jitters during the mouse drag.  Not surprising, just   
> mention it here anyway.
>
> I increase the Jackd timeout to 1000 (1 second).  The song plays to   
> the end for all the soundfonts.  Of course Fluidsynth non-verbose   
> mode give the leaast jitters, verbose mode the most jitters while   
> the Fluidsynth process is in the foreground, a little less noisy   
> when another window/process is in the foreground.  The following are  
>  about the noise/jitters in Fluidsynth verbose mode.
>
> Unison.sf2 seems to give the least noise/jitters for me.  It is also  
>  the smaller soundfont compare to the ones listed below.
>
> (Personal Copy's) PC51f.sf2, FluidR3_GM.sf2,   
> GeneralUser_GS_SoftSynthv1.43.sf2 are fairly noisy in Fluidsynth   
> verbose mode.
>
> SGM-V2.01.sf2 seems to give the most jitters, is the largest of   
> these soundfonts.
>
> It seems the soundfont sample size may contribute to some processing  
>  (rendering, mixing) delays perhaps?  Which may contributes to the   
> delinquency of Fluidsynth ability to respond quick enough for Jackd?
>
> I also tried vkeybd while playing the midi song.  There is no   
> noticeable delay from vkeybd via jackd to fluidsynth, which should   
> be excellent for live playing if there is no random the   
> noise/jitters at times.
>
> Jimmy

Sounds like audio underruns to me, which isn't FluidSynth specific.  I  
would make sure you are running it high priority (that you have the  
right permissions) and increase the audio count/buffer sizes till no  
more underruns occur.  Tuning a system for low latency audio is an art  
sometimes.  Setting synth.polyphony to a value which will limit the  
max CPU usage can also help, if you find that FluidSynth is using all  
or close to all CPU when using the default max of 256 voices.

Josh