Re: [fluid-dev] What is the best way start fluidsynth with zero/low latency?

[Louis B.]

Hello All,

Thanks for all your replies, Thanks for adding the Low Latency page on
the wiki page.
I will add some information for NetBook users which is perfect to put
on top of a piano.

I am sorry I put my point about QSnyth badly. I was just reflecting on
the fact that unfortunatly _very_ few users post bug reports when they
encounter a problem and that I was guilty of the same attitude when I
had a problem with QSnyth.


The point I was trying to make was that fluidsynth can be rather
difficult for non techie users to get running correctly especially
with low latency. The average users probably is not interested in midi
as they mostly use mp3 to play music. However those uses that
specifically seek out midi files can be divided into two camps --
those that want to just listen to the music (people working with music
notation etc) and those that use the midi input to play live and need
low latency. Does any body have an any idea what percentage of
midi/fluid users need low latency?

The more I think about it a fluid-start and fluid-stop script might
make it very easy for non techie users to startup fluidsynth with low
latency. It could do a "cat /proc/cpuinfo | grep MHz" to determine if
users had a low, medium or high powered machine. Now that
FluidR3_GM.sf2 is pretty good this script could automatically start
fluid with that sound font (Is FluidR3_GM.sf2 available to most Linux
distribution? are there any licensing restrictions with
FluidR3_GM.sf2?). It is just an idea anyway.

There is always the problem with underruns,  My atom baised NetBook is
probably a good example of the absolutely the lowest spec machine that
could run with low latency. Hopefully the main stream Linux
distributions will improve to guarantee a quality of service to
fluidsynth.

Thanks

L o u i s

>> PianoBooster is a MIDI file player that teaches you how to play the
>>  piano. see:
>>
>> http://pianobooster.sourceforge.net/



On Fri, May 22, 2009 at 2:20 AM,  <address@hidden> wrote:
> Hello Louis,
>
> Glad things are working for you.  As for having a page somewhere with
> information on getting low latency from FluidSynth, sounds like a good idea
> to me.  I added a wiki page with some initial information, which is
> accessible from the FluidSynth documentation page.  Feel free to add to it
> or change it.
>
> http://fluidsynth.resonance.org/trac/wiki/LowLatency
>
> Cheers.
>
> Josh
>
>
> Quoting "Louis B." <address@hidden>:
>>
>> Hi All,
>>
>> Wow thank you all very much, I have been struggling with this problem
>> for years now trying to get low latency synth on linux. Poring over
>> the help and man pages trying to solve this problem many times but
>> with no luck. I just thought this is was how Linux was, things never
>> working quite properly.
>>
>> the line did if for me is <q>you can try "plughw:0"</q>
>>
>> the full command line that works for me on my net book is
>>
>> fluidsynth -C0 -R0 -r22050 -l -o midi.alsa_seq.id=fs  -a alsa -o
>> audio.alsa.device=plughw:0 /usr/share/sounds/sf2/FluidR3_GM.sf2
>> /usr/share/sounds/sf2/FluidR3_GS.sf2
>>
>> I have now got some decent sounds that are usable on my Piano (my
>> piano is not near my main computer hence the netbook.)
>>
>> The only problem is that now the ubuntu volume controls to do not work
>> with the fluid synth audio (i have not tried all the things other
>> people suggested yet). But a least Piano Booster is now usable on
>> Linux for people who do not have a hardware synth. Brilliant!
>>
>> I feel that it is important to present this information to non techie
>> users so that they will have a positive experience of Linux and of
>> fluid synth. I could put up a page (on the PB site) for getting low
>> latency for all the different distributions. So does that command line
>> above work on your distributions. If not please can you all post
>> __TESTED__ command lines that work for other distributions on the
>> lowest spec machine you can get your hands on. (I know there is Qsynth
>> but I had a bad experience of it with it crashing and like most users
>> I did not post a bug report).
>>
>> I know there is also jack -- but that also just adds unnecessary
>> complication. I just want fluidsynth to work with low latency. There
>> should be a way to start jack automatically (and fluid synth for that
>> matter) behind the scenes without the user being aware of it. ie it
>> all just works. I am also not keen in integrating fuildsynth into PB
>> as i don't want PB to get bloated.
>>
>> Oh dear, this has just turned into a bit of a rant but hopefully it is
>> all fairly positive. Thanks again, fluidsynth it is fantastic and I
>> really do appreciate all your hard work and I can fully recommend it
>> to others.
>>
>> Thanks
>>
>> L o u i s
>>
>>
>> PianoBooster is a MIDI file player that teaches you how to play the
>>  piano. see:
>>
>> http://pianobooster.sourceforge.net/
>>
>
>