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No longer able to edit so replying to myself: Taken from another post of mine about widevine 7 months ago where we was discussing why the RaspberryPi couldn't support 1080p Netflix (https://news.ycombinator.com/item?id=15594460 and a link to the comment chain to make it easier for anyone reading - https://news.ycombinator.com/item?id=15586844)

> As far as I understand it there are 3 security levels to widevine Level1 being the highest and 3 being the lowest.

> Level 1 is where the decrypt and decode are all done within a trusted execution environment (As far as I understand it Google work with chipset vendors such as broadcom, qualcomm, etc to implement this) and then sent directly to the screen.

> Level 2 is where widevine decrypts the content within the TEE and passes the content back to the application for decoding which could then be decoded with hardware or software.

> Level 3 (I believe) is where widevine decrypts and decodes the content within the lib itself (it can use a hardware cryptographic engine but the rpi doesn't have one).

> Android/ChromeOS support either Level1 or Level3 depending on the hardware and Chrome on desktops only seems to support Level 3. Kodi is using the browser implementation (at least when kodi is not running on Android) of widevine which seems to only support Level 3 (So decrypt & decode in software) and therefore can not support hardware decoding. But that doesn't mean that hardware decoding of widevine protected content can not be supported on any mobile SoC. Sorry if I gave that impression.

> When a license for media is requested the security level it will be decrypted/decoded with is also sent and the returned license will restrict the widevine CDM to that security level.

> I believe NetFlix only support Level 1 and Level 3, which is why for a while the max resolution you could get watching NetFlix on chrome in a desktop browser was 720p as I believe that was the max resolution NetFlix offered at Level 3 and we had to use Edge/IE(iirc) to watch at 1080p as it used a different DRM system (PlayReady) and why atm Desktop 4k Netflix is only currently supported on Edge using (iirc) Intel gen7+ processors and NVidia Pascal GPUs (I don't know if AMD support PlayReady 3.0 on their GPUs as I don't have one so not really had the desire to investigate, I'm guessing that current Ryzen CPUs do not as they currently don't have integrated GPUs).




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