The phrase refers to software or online services that facilitate the acquisition of audio tracks, specifically in the MP3 format, from multimedia content hosted on the YouTube platform. As an example, a user might employ such a tool to extract the audio component of a lecture or a song from a video on the aforementioned service, saving it as an individual audio file.
The utility of these tools lies in their ability to provide access to audio content separate from its video counterpart. This is beneficial for users who wish to listen to content offline, conserve bandwidth, or isolate audio elements for personal use, such as creating remixes or study aids. Historically, the demand for this functionality arose from the desire to repurpose online multimedia content for a wider range of applications, predating the widespread availability of dedicated audio streaming services.