Use playbin for audio decoding
Submitted by Victor Toso
Assigned to Spice Bug List
It was recommended to me in the past  to use playbin as it easy to maintain in the long-term. It would also be possible to have software volume control in case the sink/src does not implement it, which is the case of alsa plugins . One downside is a few more things elements to include in the windows build.
The request is from linux users that don't rely on PulseAudio -> https://bugs.freedesktop.org/show_bug.cgi?id=93544#c36