MPD for DASH

[fredfung]

Hi guys, Is it possible to get dashmpd file for DASH stream?
I find a json node named "dashmpd" in youtube web page, for example, it's value is "http://www.youtube.com/api/manifest/dash/id/16b2ba37875bfa29/cmbypass/yes/upn/EaDZLjIpbN8/cp/U0hWTVhOTl9ITkNONl9QSFJBOlVhQlU2bnFNclNn/sver/3/fexp/926400%2C932245%2C930102%2C914073%2C901453%2C929117%2C929121%2C929906%2C929907%2C929922%2C929127%2C929129%2C929131%2C929930%2C936403%2C925726%2C936310%2C925720%2C925722%2C925718%2C925714%2C929917%2C906945%2C929933%2C920302%2C906842%2C913428%2C919811%2C913563%2C919373%2C930803%2C938701%2C931924%2C936308%2C909549%2C901608%2C900816%2C912711%2C904494%2C904497%2C939903%2C900375%2C900382%2C934507%2C907231%2C936312%2C906001/as/fmp4_audio_clear%2Cwebm_audio_clear%2Cfmp4_sd_hd_clear%2Cwebm_sd_hd_clear/expire/1378830034/s/DBC6BCB9A7892BE3EEF1F21043F6518F2267F1.5237B1C396E4A266C92E1CF617D540DA938785EB578C41B/ip/1.171.16.166/key/yt1/ipbits/8/source/youtube/sparams/as%2Ccmbypass%2Ccp%2Cid%2Cip%2Cipbits%2Csource%2Cexpire".

I try to refine the URL (fix it to http://www.youtube.com/api/manifest/dash?id=16b2ba37875bfa29&cmbypass=yes.......) and replace signature ( CB9A7892BE3EEF1F21043F6518F22D7F165237B1.396E4A286C92E1CF617D540DA93B785EB578C416 ). But, HTTP 403...:(

Please help me, thanks.

[jaimeMF]

I tried some time ago and you could directly use the dasmpd url to get the manifest with urls that linked to each format, but now it doesn't work, you'll probably have to manipulatete url, I've tried decrypting the key and replacing '/s/' with '/sig/', but it doesn't work. We can find a way to do it if you can find a situation where Youtube downloads the manifest, otherwise it would be quite difficult.

[fredfung]

Thank you @jaimeMF .
I can download dashmpd now if we decrypting the key and replacing 's=' with 'signature='.
It doesn't work yesterday because youtube has changed decrypt algorithm for length 85

[jaimeMF]

I guess you are transforming the url to http://www.youtube.com/api/manifest/dash?id=16b2ba37875bfa29&cmbypass=yes....... converting each pair of /param/value to &param=value, but you can also just replace s/{encrypded_sig} with signature/{decrypted_sig} and it also works, it may be easier than refining the url.

[fredfung]

Yes, I convert url as you say, and replacing 's/encryped_signature' only is a better way.Thanks for your help

[nschwermann]

Is this api/manifest documented anywhere? What is the sig?