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LPC: Linux audio: it's a messLPC: Linux audio: it's a messPosted Sep 21, 2008 8:27 UTC (Sun) by mlankhorst (subscriber, #52260)In reply to: LPC: Linux audio: it's a mess by adamgundy Parent article: LPC: Linux audio: it's a mess
Alsa already had oss support in the form of aoss, which hooks all ioctl's
and read/writes to /dev/dsp, so the only thing new is that this form uses CUSE instead of hooking function calls with preloading.
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LPC: Linux audio: it's a mess Posted Sep 21, 2008 22:20 UTC (Sun) by adamgundy (subscriber, #5418) [Link]
the point is that aoss (and other variants) can't catch *everything* (mmap, etc), but I believe CUSE is intended to allow a user space process to catch all the same stuff as the kernel mode emulation can.
also, aoss is a pain for most users, because they have to start the program they want to 'emulate' under aoss, typically from a command line. CUSE just sits there as a daemon, waiting for any process to attempt to use /dev/dsp.
LPC: Linux audio: it's a mess Posted Sep 21, 2008 23:03 UTC (Sun) by mezcalero (subscriber, #45103) [Link]
PA has "padsp" which is similar to "aoss".
However, this kind of virtualization is always imperfect, won't work for more complex applications that use mmap, or make assumptions about timing and hardware that a software sound server cannot meet.
Doing emulation with LD_PRELOAD is always hacky, incomplete, and can only be a temporary solution that only works in very specific cases.
Lennart
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