Youtube login, hardware/network questions

[davidshumway]

Does this library happen to facilitate logged-in youtube listening?

In terms of the stream, is the video downloaded alongside the audio in the stream, or is the audio only streamed? For example, in terms of network traffic would the network show the equivalent of a regular video+audio stream being accessed on the network, or would only the audio portion show up?

Also, in terms of hardware, any ideas as to which parts of the computer are used in the process of playing audio? Is it the sound card only? Is the video card utilized at all, i.e., as is done when playing a video?