Ubuntu 13.04 is shipping a fork of mplayer (mplayer2) by default. If you are not able to hear audio and encounter the following error on Ubuntu 13.04 while playing any file in mplayer or smplayer:
Requested audio codec family [mpg123] (afm=mpg123) not available. Enable it at compilation. Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders AUDIO: 44100 Hz, 2 ch, floatle, 96.0 kbit/3.40% (ratio: 12000->352800) Selected audio codec: [ffmp3float] afm: ffmpeg (FFmpeg MPEG layer-3 audio)
you have mplayer2 installed. Remove it and install mplayer to get things working. I tried searching for some easy solution with mplayer2 (rather than a compilation) but didn’t find any yet.