RE: [linux-audio-dev] Linux Audio Hardware Selection

Hi all, I was looking for a good, up-to-date documentation pointer upon software features provided by alsa. But I'm new to this architecture and I might be "intoxicated" by some kernel streaming architectures : is there a kind of hardware abstraction with ALSA, e.g. features that are managed by the software at usr or kernel level, in a +/-transparent way, when the HW does not provide them ? My understanding is that Alsa does not provide multiple device open (a second open can be blocking, or return with an error, but won't succeed, as no sw mixing is available). is there anything that can be emulated by alsa on user request, when the hw cannot ? (for instance frequency change, frame conversion (n channels to m channels) etc...). How would you implement such thing ? With a kind of abstraction layer daemon, that exports the same api but perform missing hw features ? Could the LADSPA plugin architecture be a solution to implement multiple device open ? tx Marc.