I'll have another look at Pavel's decoder, I thought it was basically the wsjtx one with iq input, does it have further optimizations?
Another advantage of passing the 77bit packet is that it allows control over hashed callsigns which I have ignored up until now.
The websocket connection could be used for decoders, it already has an iq feed option and I mean to add a sample rate setting for it, zmq and gRPC are other options that I can easily support, I'm sure others will be interested in connecting to decode servers so they may have views.
The client server mode that is almost ready will allow running many copes of spark on different computers and share the bandwidth of whatever radios are connected, this effectively allows 'cluster decoding'.
Too many options, not enough time :)
73 Alan M0NNB