rip video from cache browser

[lomero]

i have one link to video encrypted. if play from my browser, no problem. also if don't play video, however, it is downloaded to the browser cache.
yt-dl and streamlink not work (unable to obtain key file), then i want try to recover from browser cache.
the only one who does this is VideoCacheView but in this specific case it detects nothing.
the individual files taken from the browser cache cannot be played because they are encrypted.
I don't understand why (in offline mode) I look through the browser at the part of the video downloaded in the cache, it works.
while if I look at the single file in the cache with VLC I don't see it ...

suggestion to rip video (decrypted) from cache browser?

[jagabo]

Oops, never mind.