Youtube is using cipher signature for some of the videos when the use_cipher_signature = true
in the dictionary returned through
http://www.youtube.com/get_video_info?&video_id=Video_Id
Example id: _JQH3G0cCtY
Ciphered signature is actually the scrambled signature which anybody can debug with few sets of working signatures. But Youtube keeps on changing the scrambling algo. I have seen few Youtube video downloader which are working smoothly without being affected through this changing game. I think they are checking the player and extracting the decode script from the player file and hence it keeps them going.
I need some help about the actual technique to use in this case. I am aware of 'youtube-dl' - a python program to download the videos. As I am not good in python, I think that they are using the same approach.
Also there is a user-script JS file available here: http://userscripts.org/scripts/show/25105 , which is doing the same thing.
Any help about the sane approach to decode the cipher code in PHP or JS will be appreciated.
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