[REQUEST] Fetch audio key from seektables & MP4 Format

[KagChi]

You can fetch audio key from seektables then try to decrypt the pssh_widevine to get the audio key
the url are https://seektables.scdn.co/seektable/fileId.json file id are hex from audio formats

Seems you can only fetch MP4_* audio key

[kokarare1212]

This is the first time I have heard of the MP4 format.
Does that mean they will be decrypted by Widevine?

[KagChi]

Does that mean they will be decrypted by Widevine?

No, you can decrypt the track with current strategy. just fetching the audio key from the seektables without requesting it from mercury client.

response = self.__session.client() \
    .get("https://seektables.scdn.co/seektable/{}.json".format(util.bytes_to_hex(file_id)))
if response.status_code != 200:
    raise IOError("{}".format(response.status_code))

json = response.json()
if not json:
    raise IOError("Seektable seems empty")
                
wideresponse = self.__session.client() \
    .post("https://integration.widevine.com/_/pssh_decode", json.get("pssh_widevine"))

widejson = response.text()
if not widejson:
    raise IOError("Widevine decoders seems empty")

json_start = widejson.find('{"algorithm":')

# Parse the JSON object
json_data = json.loads(widejson[json_start:])

return base64.b64decode(base64.urlsafe_b64encode(json_data.get("key_ids").pop(0).bytes))

here is the snippet. why not use PSSH module? the project doesnt suppport latest protobuf. so we are safe to fetch higher MP4 quality without premiums. since the seektables were available for all MP4 formats.

Example:

https://seektables.scdn.co/seektable/12464744a06d5c7e4a8848266682d78228e529a1.json (MP4_256) HIGHEST QUALITY 
https://seektables.scdn.co/seektable/a6281f4b53c19695ae51216133e14f2eceeb2582.json (MP4_128) LOWEST QUALITY

keyIds are the key to decrypt the track. they are in base64 so convert it to hex first.

[KagChi]

Any updates on this?

[kokarare1212]

I do not currently have the time to add features, if you can write the code, I will merge it after reviewing it.

[KagChi]

i have the implementation, but i cant test it. the proto seems need to build? do u mind to test it out?

and also, i dont really know MP4_128 proto code. only guessing it... 😂

[kokarare1212]

There are a lot of unknowns about MP4_128.
For now, we will wait until we see movement in other related libraries...