A video is considered legally unfree if any portion of the video was previously licensed under a proprietary license that restricts usage and prevents derivations and commercial usage.
The legal concept of fair use of a third party's music or other content in one's own video work may protect against DMCA takedowns.
The case focuses on the usage of a song licensed by Universal that was used in a YouTube video of a dancing toddler.
Instead, most known free video content is under a Creative Commons license and other, non-media-type-specific free content licenses, or within the public domain as the video's copyright has already expired.
While the discussion on free video is related to an extent to the advocacy for freely-licensed data compression technologies such as Theora for video and Ogg Vorbis for audio (particularly in the 2008 debate on whether to include the two within the WHATWG draft for HTML5 on multimedia), the latter argument is related more to the advocacy of free software.