Hi Rui, On Friday 08 October 2010, Rui Fan wrote: > Hi everyone, > > I'm using fluidsynth 1.1.2 under Ubuntu 10.04, with latest realtime > kernel, connect to RoseGarden 10.04, playback some midi files. > Sometimes I encounter this error message, and all sounds off. > > ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// > fluidsynth -C0 -R1 -l -a alsa > /home/fanrui/tools/music/soundfont/SGM-V2.01.sf2/SGM-V2.01.sf2 > FluidSynth version 1.1.2 > Copyright (C) 2000-2009 Peter Hanappe and others. > Distributed under the LGPL license. > SoundFont(R) is a registered trademark of E-mu Systems, Inc. > > Type 'help' for help topics. > > > fluidsynth: error: The audio device error: Input/output error This may be produced by several things: an audio hardware device malfunction, problems with other hardware components, the ALSA device driver, other Linux kernel components, other software, ... almost anything.
> fan...@fanrui-desktop:~$ uname -a > Linux fanrui-desktop 2.6.31-11-rt #154-Ubuntu SMP PREEMPT RT Wed Jun 9 > 12:28:53 UTC 2010 i686 GNU/Linux > > Does this mean fluidsynth is not compatible with realtime kernel ? > On my laptop there is a rather big latency when using default kernel, > so I'm trying realtime kernel. On my other desktop computers, the > latency for default kernel is accepted. FluidSynth latency depends on several factors. A very important one is the audio buffer size and periods. You can find more information here: http://sourceforge.net/apps/trac/fluidsynth/wiki/LowLatency The problem is that reducing the buffers increases the probability of underruns on the audio hardware, producing noises/artifacts and input/output errors. To mitigate this problem, you can run a realtime kernel and assign realtime priority to the synthesizer process. Since FluidSynth 1.1.2, you can use rtkit, but the classic way is the allowing rtprio to your user/group in limits.conf, http://linux.die.net/man/5/limits.conf http://apps.linuxaudio.org/wiki/real_time_info Anyway, even if you use the same operating system, kernel version, priority settings, environment, processor, etc. a critical factor is the audio hardware device. Professional or good quality audio interfaces typically allow much smaller buffers, and lower latency as a consequence than cheap/low quality devices. If your laptop has an HDA sound hardware, it is probably the culprit. Regards, Pedro _______________________________________________ fluid-dev mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/fluid-dev
