Python (v2.7) requires to install plugins to play media files of the following type: Windows Media Audio 8 decoder

when trying to convert some audio files to Ogg Vorbis using Sound Converter I get the following error:

Python (v2.7) requires to install plugins to play media files of the following type: Windows Media Audio 8 decoder

Any idea where to get this codec or how to install it?

I'm using Ubuntu 14.04 LTS

Make sure to install both mplayer and lame. To do this open a terminal (Ctrl+Alt+T or Super+T) and paste (Ctrl+Shift+V) the following line and hit Enter to run:

sudo apt-get install mplayer lame

Enter your password when prompted, then navigate to the folder containing your WMAs and run the following command in the same terminal:

for i in *.wma ; do mplayer -vo null -vc dummy -af resample=44100 -ao pcm:waveheader "$i" && lame -m j -h --vbr-new -b 320 audiodump.wav -o "`basename "$i" .wma`.mp3"; done; rm -f audiodump.wav

This will create 320 kbps MP3s in the same directory, keeping the original files.
These MP3s will not contain ID3 data (title, artist, album, etc). GMusicBrowser is excellent for modifying this information.

Thanks to Rory Alsop for the one-line script, which needed a slight update. Here he also shows a way to make a single command run the script.