One way of converting online videos to MP3 files is using converters, available on sites such as Convert2MP3.net, ClipConverter.cc, VidToMP3.com and YouTube-MP3.org, as of July 2015. For offline conversion, you can use an application such as Free Video to MP3 Converter.
Convert2MP3.net supports conversion of videos from YouTube, Vevo, Dailymotion and Clipfish. To convert a video to a clip in MP3 format, paste the video's URL in the field on the home page, select MP3 format on the drop-down menu adjacent to the field, and then click on Convert. Wait for the conversion process to complete, set the tags for the MP3 file or skip the process, and then click on Download to save it on your device. The converters on ClipConverter.cc, YouTube-MP3 and VidToMP3.com use a similar procedure. However, YouTube-MP3's converter only works with YouTube videos.
To use Free Video to MP3 Converter on your computer, first launch the application, and click on Add Files to select an input video file. After selecting a video in a supported format, choose an output name by clicking Output Name or leave it to be the name of the video. Select the output directory, select the quality you want for the MP3 file, and then click on Convert.