58 lines
2.6 KiB
Markdown
58 lines
2.6 KiB
Markdown
# Obtaining PSSH
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## Getting started
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3 methods to find PSSH:
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1) The simplest one: PSSH is clearly indicated in MPD file. Download MPD file (browser add-on "MPD Detector" will give you MPD link or filtering for `mpd` in the `network` tab of devoloper tools (ctrl + shift + c)), open it with Notepad, search for pssh value.
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2) If there is KID, but no PSSH in MPD, calculate PSSH by using KID:
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Using [this](https://tools.axinom.com/generators/PsshBox "this") website you can get the PSSH by entering in the `urn:uuid:` into the `System ID` field and entering the `cenc:default_KID=` into the `KEY IDs` field without the quotes `""`
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Eample:
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![One:](example_one.png?raw=true "One")
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3) [EME Logger Script](https://greasyfork.org/en/scripts/373903-eme-logger "EME Logger Script") (installed on [Tampermonkey](https://www.tampermonkey.net/ "Tampermonkey") add-on) will give you init data. That's your PSSH. This can be found on Developer Tools (ctrl + shift + c) > Console, in the filter bar search for `MediaKeySession::generateRequest` you will find Init Data.
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**Optional, may be rquired:**
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If that Init Data is very very long, convert it to HEX:
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https://base64.guru/converter/decode/hex
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Here's what mine looked like before conversion.
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![Two:](example_two.png?raw=true "Two")
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After Base64 > HEX conversion, you will find a Widevine-PSSH box, this can be found easily by searching with ctrl + f and searching for `70737368`
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PSSH header is always in a `000000xx70737368` where the `xx` is varied and can be from 1-9 in both x spots.
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You always want to copy the 6 `0`'s before the xx as well.
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Example:
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![Three:](example_three.png?raw=true "Three")
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The end of the header is always then followed by 8 more `0`s, if you see this, you are in the right place.
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Once you find the header start at the beginning 0 from the header and copy until the end of the converted hex, it should look like this
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Example:
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![Four:](example_four.png?raw=true "Four")
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In this case the full value was `000000577073736800000000edef8ba979d64acea3c827dcd51d21ed0000003708011210162f7d326cf24f6dbd1319bc572bbc151a0b62757964726d6b65796f732210162f7d326cf24f6dbd1319bc572bbc152a024844`
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convert the hex back into base64 using
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https://base64.guru/converter/encode/hex
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Example:
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![Five:](example_five.png?raw=true "Five")
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In this case we got the PSSH value of `AAAAV3Bzc2gAAAAA7e+LqXnWSs6jyCfc1R0h7QAAADcIARIQFi99MmzyT229Exm8Vyu8FRoLYnV5ZHJta2V5b3MiEBYvfTJs8k9tvRMZvFcrvBUqAkhE`
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Congrats, you have the PSSH!
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4) Using init files
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You can use [this tool](https://cdm-project.com/CDM-Tools/Obtaining-PSSH/src/branch/main/get_pssh_from_init.py "this tool") to obtain the PSSH from an init file |