My current setup is mpd server on a RPi connected via pulseaudio to an airport express sink which in turn is connected to my receiver/amp as described in Redirect audio to another AirPlay device
In this setup I get choppy sound coming from the receiver. However, I have troubleshooted the problem to mpd because of the following:
1) It is not a pulseaudio + raop since running
ffmpeg -i my-audio-file.mp3 -f pulse "my-sink.local" does play well through the receiver via airplay.
2) It is not an issue of connectivity of mpd since connecting to mpd either with mpc locally or a client from a different computer plays well when mpd is configured to use the alsa sink and a headset on the RPi.
I suppose it is some form of buffering on mpd that is conflicting with airplay/raop but I do not know where to look, any help will be appreciated.