raedwulf / alsaequal

GNU Lesser General Public License v2.1
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Multi-channel support? #12

Open pyInter opened 1 year ago

pyInter commented 1 year ago

The lib is not working well with plugins of stereo input or output. As stated in the README, alsaequal was developed for and only tested with Eq CAPS LADSPA plugin. I guess alsaequal assumes the plugin to be single-channel-in-and-out, which is not always the case in audio post effects. Most stereo-wise plugins, in both CAPS and other LADSPA plugin libraries, process multi-channel input and/or yield multi-channel output. Applying these plugins directly may lead to memory error due to the incorrect port connection. How should the number of plugin instances be determined? And what is the proper way to map the input channels with upstream and the output channels with downstream?

Case I: we need 2 instances, each to deals with one single channel of the stereo input (i.e. Eq10, Eq4p in CAPS) |→⚫→| |→⚫→|

Case II: we need 1 instance, to deals with the entire stereo input (i.e. Eq10X2, Narrower in CAPS) |⇉⚫⇉|