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PSSH: Rework from_playready_pssh class method as normal method

This commit is contained in:
rlaphoenix 2022-08-06 13:47:09 +01:00
parent 0d13d4184b
commit 077a3aa6be
1 changed files with 23 additions and 34 deletions
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57
pywidevine/pssh.py
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@ -226,40 +226,6 @@ class PSSH:
raise ValueError(f"This PSSH is not supported by key_ids() property, {self.dumps()}") raise ValueError(f"This PSSH is not supported by key_ids() property, {self.dumps()}")
@classmethod
def from_playready_pssh(cls, box: Container) -> PSSH:
"""
Convert a PlayReady PSSH Box to a Widevine PSSH Box.
Note: The resulting Widevine PSSH will likely not be usable for Licensing. This
is because there is some data for a Widevine Cenc Header that is missing from a
PlayReady PSSH Box.
This converted PSSH will only be useful for it's Key IDs, so realistically only
for matching Key IDs with a Track. As a fallback.
"""
if box.type != b"pssh":
raise ValueError(f"Box must be a PSSH box, not {box.type}")
if box.system_ID != PSSH.SystemId.PlayReady:
raise ValueError(f"This is not a PlayReady PSSH Box, {box.system_ID}")
key_ids = PSSH.get_key_ids(box)
cenc_header = WidevinePsshData()
cenc_header.algorithm = 1 # 0=Clear, 1=AES-CTR
for key_id in key_ids:
cenc_header.key_ids.append(key_id.bytes)
if box.version == 1:
# ensure both cenc header and box has same Key IDs
# v1 uses both this and within init data for basically no reason
box.key_IDs = key_ids
box.init_data = cenc_header.SerializeToString()
box.system_ID = PSSH.SystemId.Widevine
return cls(box)
def dump(self) -> bytes: def dump(self) -> bytes:
"""Export the PSSH object as a full PSSH box in bytes form.""" """Export the PSSH object as a full PSSH box in bytes form."""
return Box.build(dict( return Box.build(dict(
@ -275,6 +241,29 @@ class PSSH:
"""Export the PSSH object as a full PSSH box in base64 form.""" """Export the PSSH object as a full PSSH box in base64 form."""
return base64.b64encode(self.dump()).decode() return base64.b64encode(self.dump()).decode()
def playready_to_widevine(self) -> None:
"""
Convert PlayReady PSSH data to Widevine PSSH data.
There's only a limited amount of information within a PlayReady PSSH header that
can be used in a Widevine PSSH Header. The converted data may or may not result
in an accepted PSSH. It depends on what the License Server is expecting.
"""
if self.system_id != PSSH.SystemId.PlayReady:
raise ValueError(f"This is not a PlayReady PSSH, {self.system_id}")
cenc_header = WidevinePsshData()
cenc_header.algorithm = 1 # 0=Clear, 1=AES-CTR
cenc_header.key_ids[:] = [x.bytes for x in self.key_ids]
if self.version == 1:
# ensure both cenc header and box has same Key IDs
# v1 uses both this and within init data for basically no reason
self.__key_ids = self.key_ids
self.init_data = cenc_header.SerializeToString()
self.system_id = PSSH.SystemId.Widevine
def set_key_ids(self, key_ids: list[UUID]) -> None: def set_key_ids(self, key_ids: list[UUID]) -> None:
"""Overwrite all Key IDs with the specified Key IDs.""" """Overwrite all Key IDs with the specified Key IDs."""
if self.system_id != PSSH.SystemId.Widevine: if self.system_id != PSSH.SystemId.Widevine: