YouTube >> Copyright and rights management >> Creative Commons

"...Creative Commons on YouTube

The ability to mark uploaded videos with a Creative Commons license is available to all creators. The standard YouTube license remains the default setting for all uploads. To review the terms of the standard YouTube license, refer to our Terms of Service. Creative Commons licenses can only be used on 100% original content. If there's a Content ID claim on your video, you cannot mark your video with the Creative Commons license. By marking your original video with a Creative Commons license, you're granting the entire YouTube community the right to reuse and edit that video...."