Detect that Widevine CDM is revoked or incompatible

[dagwieers]

If we can detect that the used Widevine CDM is revoked, we could use this as a trigger to check for an update. (If it is not working, we can't break it by trying to update the CDM).

If we would have such a mechanism, there is no longer a need to force checking for an update on upgrade. Because potentially an update of the Widevine CDM could turn a working system in a non-working system (this has happened before).

[dagwieers]

@peak3d @emilsvennesson @mediaminister Is this at all possible?

[emilsvennesson]

I'm not sure if this data is available anywhere.

However, asciidisco/plugin.video.netflix#465 could have been avoided, at least on x86. We can start comparing the supported Widevine API version with what's supported in inputstream.adaptive. There's a hidden setting in inputstream.adaptive, WIDEVINE_API we can retrieve (although I'm not sure it's been updated, ping @peak3d) and compare with x-cdm-interface-versions that's in the manifest.json file on x86.

[dagwieers]

@emilsvennesson This PR is to track if we can implement an interface to detect this. My original idea was a service that monitors for these failures, and inputstream.adaptive would then send out specific messages for use to be used and act on.

[peak3d]

WIDEVINE_API is updated, and currently version 10 is supported.
IIRC there are manifest files shipped with widevine for some platforms where the level can be picked from. For other platforms (COS IIRC) it is not the case

[dagwieers]

@peak3d How could inputstream.adaptive get triggered if Widevine failed and an action is required?
I can foresee multiple causes:

• The Widevine CDM is no longer supported by inputstream.adaptive (e.g. Kodi 17)
• The Widevine CDM used is revoked by Widevine
• The Widevine CDM is missing or broken (corrupted, or wrong architecture)

Only in the two last cases we would be able to act (offer to upgrade, or reinstall).

[dagwieers]

I wonder where this is coming from:

2019-08-23 00:32:34.232 T:1169351536   ERROR: AddOnLog: InputStream Adaptive: Decrypt Sample returns failure!