From Buzztard

This should be a bin derived element. When creating a btsong t needs a btapplication to get the bin from. Thus bt-bin would need to have a fake bt-bin-app. It will create a btsong and pass the bt-bin-app to set itself as the 'bin'.

[edit] Dummy sink

It also needs to provide a dummy btsinkmachine that it will set as a master. As btsinkmachine always uses btsinkbin, the later needs a pass-through mode. The bin needs to set the src-pad of the sink-bin as a ghost-pad (can we have an unused ghostpad?, can we make it a request pad). I don't see a way to avoid sink-bin right now. Thus we would need to extend the BtSinkBinMode with passthrough mode. In this mode it would use the src-pad of output-volume for the sink-bin's ghost-pad.

[edit] Typefinders

We somehow need to wrap the songio-detect mechanism into a typefinder.