[SW] Rhythmbox and Quod Libet don't play music

I have used Rhythombox and Quod Libet for listening to music, podcast, and internet radio. But I didn't listen to music on my PC for a while, and these days I encountered a problem when I used Rhythombox and Quod Libet to open my music files. Both of them cannot play the ogg files. I tried to remove and reinstall them, but it didn't work.

Finally, I found a post from ``rhythmbox : does not play the songs at times. When I click play song, no response''.

So the solution is to change the sound setting to ALSA. The problem for me now is that I don't remember why I changed the sound setting to PulseAudio...