recently YouTube changed again the code for videos with encrypted signature, so a fix is needed (just for this kind of videos, not for all) for YTD to work properly again.
When the video you’re trying to download is affected, all formats appear with a size of 0 B. Then every format will fail to download.
I’m aware of the problem, so please avoid sending logcats in regards, but standby for a patch.
I’ll do it ASAP.
EDIT: fix found, see next blog post!
Original Link: http://dentex.github.io/blog/2015-11-10/changes-in-youtube-code/
If you want to reprint it, please do under the CC BY-NC-SA 4.0