Rated 5 out of 5 stars

Problem: every file that I want to download from youtube as MP3 end up with XXX mb in size, as it download s video file and adds extension MP3..? What do to?

This review is for a previous version of the add-on (3.0.4.1-signed). 

Hi, Try uninstalling the plugin and reinstalling with 3.1.0 and trying a few downloads. If that still fails go to tools -> youtubeMP3Podcater -> Click the Troubleshooting Tab. You'll find a slider marked 'Debug Level'. Set it to 'ALL' and try a download. Then check your Home directory (/home/ in Linux, /Users, and in Windows you can go to Start -> Run and type in %HOME%). Look for a file called ffmpeg*.log, but instead of the * (star) it'll be a date, like "ffmpeg-20131225-124157.log" :). Send me this file. It'll tell me why the conversion is failing.