The “roundedness” is a known issue and is being worked on. At some point it worked without “roundedness”, see for example this observation.
It is of course possible to run wxtoimg instead. I have been doing that on my station almost a year now, but it did require code changes that I now have to maintain when satnogs software is updated.
hello csete,i got you aptdec project on github yesterday,but it can’t work now,the output show there are no initsnd/initalsa/endsample interface, my env is ubuntu 18,do you got any suggesetion for me ,thanks.