Hrmm... I'm not sure. At any point in the protocol is there a "copyright bit"? It only takes one bit, and it doesn't even have to be documented as serving tha

Hrmm... I'm not sure. At any point in the protocol is there a "copyright bit"? It only takes one bit, and it doesn't even have to be documented as serving that purpose. The StreamboxVCR case ended up cementing into law (because the Streambox people ran out of money and couldn't appear to answer the last appeal by RealNetworks) that disobeying one undocumented bit is all it takes to run afoul of section 1201 of the DMCA. I imagine there might be such a bit in the YouTube stream but I don't know. I'm also not sure how you could defend in court that creating the temporary copy in memory for purposes of playing a stream is given permission, but creating a more permanent one is not. Courts have held that transitory copies in memory are actual copies, and can constitute real infringement, but obviously YouTube gives implicit permission to users to the creation of that copy, and youtube-dl doesn't actually create any additional copies beside that, it just keeps it.