This IE should be full-featured. Public videos can be downloaded without login, e.g: https://www.facebook.com/video/video.php?v=696729990595 Private videos need login, and subject to login rate limit of a couple of tries / minute.
The "playlist_prefix" parameter was missing when parsing playlist urls that match the recently added format, e.g.: http://www.youtube.com/user/stanforduniversity#g/c/9D558D49CA734A02 For these URLs (basically, for every playlist type so far, except the artist list) playlist_prefix has to be equal to "p" for correct exctraction.
Artist playlist pages have different format compared to user playlists, thus more format checking is needed to construct the correct URL. From the artist playlist this method downloads all listed below the "Videos by [Artist Name]" header, plus usually there's one more video on the side, titled "Youtube Mix for [Artist Name]", which has a link format that currently cannot be distinguished from the other videos in the list.
This file stamp setting is very relaxed. If there's any problem along the way (no last-modified header, bad time string format, no time set privileges,...) or if nothing is downloaded (e.g. using resumed download but the file was already complete) then nothing is done.
When using youtube-dl within scripts, it is very useful to know what will be the final output filename with all the title settings and filename templates applied. Add option to the quiet mode operations to print that info. For this I had to move the filename-generation into its own function. As much as I can tell it should work almost always well, ie. not to break things if one not actually interested in the title, like in case of other forced printing. That is, unless there's an invalid system charset or the user specified a wrong output template. In that case probably could be assumed that the user does have a problem (the former) or did want to mess with the filename (the latter). Signed-off-by: Gergely Imreh <firstname.lastname@example.org>