> > "Hardware mixing" in ALSA terminology refers to the mixing of multiple > > sound sources from the PC by the hardware. For example, mplayer > > output and system notification sounds. > > Yeah. I suspect (and Mark apparently did, too) that the original > poster meant to ask about hardware monitoring, which is completely > different :-) > > Explanation here: > http://ardour.org/manual/recording/monitoring

Is there a commonly understood meaning? I guess I'm uncommonly (or commonly for me) in the dark about that.

its not true to say that with ALSA, they support what is commonly understood as h/w mixing. you cannot do independent open's of several subdevices and get the output of each subdevice mixed down to the outputs. yes, they do have a very powerful h/w matrix mixer, but it is not accessible via a series of independent subdevices. it also is not supported by the ALSA mixer API at this time.

it means that you can have up to N apps all using the same card without any s/w mixing going on. each one calls snd_pcm_open() which internally calls snd_pcm_open_subdevice() and assuming the subdevices are not all busy, it will work. a subdevice is a "stream" that always sends its signal to the outputs associated with the PCM device, but can be opened and closed independently.