'Twas brillig, and Marcus Weigelt at 07/04/10 11:01 did gyre and gimble:
Hi,
I´m having an external PCM plugin that should do some processing on the audio. That part works fine. Now I´d like to have some way to modify the way to give some parameters to the plugin to tell it how the processing is done (eg. set delay time, pan, attack time, ...). I´ve searched the web for days and hours, but could not really find something. On the alsa mailing list there was a similiar question three years ago, and the answer was, that one could create user-space control elements in the plugin. How is that done? I could not find examples or good documentation about it. Did I miss something out? Can anyone give me a hint, maybe a link to some docs about it or source of a PCM plugin creating/using user space control elements? Thanks a lot.
Try looking at the PulseAudio plugin. It presents userspace sliders to control the volume. If I've not misunderstood your request this should do what you need.
Col