4K UHD Streaming Question

If I shoot a 4K video on my smartphone which, although it records in 4K, doesn't have the resolution to display the video in true 4K, and then upload it to YouTube - if I watch the video on YouTube via Apple TV HD on a 4K TV, am I seeing a true 4K picture?

Sorry about what appears to be a daft question - and the length of that first sentence/paragraph...

via International Skeptics Forum http://ift.tt/1K5xO5s