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Thread: A failed attempt to download/decrypt DRM protected video from a viki.com

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    A failed attempt to download/decrypt DRM protected video from a viki.com

    I have already installed TamperMonkey from https://addons.mozilla.org/en-US/firefox/addon/tampermonkey/ (I am on Firefox, but Chrome is at https://chromewebstore.google.com/detail/eme-call-and-event-logger/cniohcjecdcdhgmlofniddfoeokbpbpb ) and then https://greasyfork.org/en/scripts/373903-eme-logger in Aim to display in a web browser developer console, Console tab, the details of the encrypted stream.

    Restart the browser.

    On a new browser tab, opened a dev. console (F12), Network tab and opened URL:
    https://manifest-viki.viki.io/v1/license?video_id=1005581v&app=100000a&h_timestamp= 1650716082&app_ver=4.0.97&dt=dt3&sig=a8fa82aadfa1c 52075aba362c22351d4bb392292

    it returned: {"vcode":3,"error":"invalid timestamp","current_timestamp":1726117521}

    I am not logged in to viki (have no account, I am unsure if i need any particular one).

    I have not been able to find any PSSH anywhere in a dev. console on viki.com.

    I can see some EME-Logger.user.js:* entries on a Console tab, like:
    Init Data: AAAAV3Bzc2gAAAAA7e+LqXnWS...
    Message: CAESqgwKugsIARKeCgrcAggCEhBIa4PbkkFF6EtcACIHk3RqGI nHtK...
    Response: CAISvQEKKAoQrAknzJp8mBIuH1dfp2PQ7hIQU...
    Key Statuses:
    [USABLE] iSlvMc7qQJKWVf3cDS9HqQ==
    Someone suggested: On the Console tab filter for "Init Data:" without the quotes.
    and it shows:
    [EME] (CALL) MediaKeySession::generateRequest
    Session ID: (not available)
    Init Data Type: cenc
    Init Data: AAAAV3Bzc2gAAAAA7e+LqXnWSs6jyCfc1R0h7QAAADcIARIQiS lvMc7qQJKWVf3cDS9HqRoLYnV5ZHJta2V5b3MiEIkpbzHO6kCS llX93A0vR6kqAkhE
    I suspect that the Init Data: AAAA... is so called PSSH key which is requested by some utilities meant to decode DRM protected videos.

    Same AAAA string can be returned by the command: curl https://bitmovin-a.akamaihd.net/content/art-of-motion_drm/mpds/11331.mpd|grep -i pssh
    (maybe it will run not only on Linux but on Windows too)

    I can find some tool for decryption keys https://emarsden.github.io/pssh-box-wasm/get-license/ , but it wants a CDM device in a .wvd format (at https://github.com/devine-dl/pywidevine is some utility that may create it, but I have not understood how to do it).

    There is also https://cdrm-project.com/ yet it is not helpful in telling what i am filling wrong and which format is correct.

    I am not using Discord in order to use http://getwvkeys.cc which is said to give a decryption keys, which can be then used in the commands:

    mp4decrypt.exe --key 5d881c8bb82448d89de510c512a19674:7e9ea1e9a7f67cbe9 8a07aedd43c4ab7 myV.mp4 myV_dec.mp4 # decrypts video myV.mp4
    mp4decrypt.exe --key 5d881c8bb82448d89de510c512a19674:7e9ea1e9a7f67cbe9 8a07aedd43c4ab7 myA.m4a myA_dec.mp4 # decrypts audio myA.m4a
    ffmpeg -i myV_dec.mp4 -i myA_dec.mp4 -c copy final.mp4 # merges the decrypted video and audio files
    There seems to be some not so intuitive alternative https://github.com/medvm/widevine_keys , but that did not work for me.

    If there is some simple way to get the decryption keys or the decrypted video file, please kindly share it.
    Last edited by Fli; 09-12-2024 at 09:39 AM.

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