So we've got it narrowed down to an Is-Not/Is-Too argument. I am not an intellectual-property rights lawyer, but my understanding is as follows:
I expect that the book will remain under copyright until either 2086 (1991+95), or 70 years after the death of the (currently living) author. The film might extend a few years later. PBS (a private corporation) normally rents broadcast rights to the individual broadcasters, for a specified period of time. They don’t give it away for free. The content creator (possibly a 3rd party under contract) normally retains their rights, and may then rent the rights to someone else, perhaps in another format.
This film series could be in the public domain if the owner gave it away using a “copyleft” type contract. Do you have special knowledge that this was done?
I believe you posted it in good faith, without meaning harm. I should have used a silly looking pirate.
