[fluid-dev] performance issues on iphone

[Ruben Zilibowitz]

Hi. I'm playing around with soundfonts on iphone and I decided to try to 
compile fluidsynth for iphone. Here is what I found:

1) I had to use fluidsynth 1.0.9 since I didn't want to build glib and all the 
other dependencies for iphone.
2) It works well in the simulator, as in I can play midi files perfectly.
3) On the iphone hardware performance isn't good. The sound is choppy and 
sometimes drops out when too many notes are occurring.
4) Also I had to write my own audio driver since coreaudio works differently on 
iphone to macosx.

My main question is how to resolve point 3, above. Are there any tips people 
have for improving performance. I'm using the SYNTHGMS.SF2 soundfont which is a 
pretty small general midi soundfont.

Another observation I made about my audio driver. I set:
dev->buffer_size = 4096;
This results in good playback performance on the simulator. For ipad/iphone 
hardware.
dev->buffer_size = 8192;
seems to be required, whilst this creates distortion in the simulator.

If anyone has any tips or feedback about any of this, that would be good.

Regards,

Ruben