[Bug 21016] Please split Clear Key into a separate optional specification

https://www.w3.org/Bugs/Public/show_bug.cgi?id=21016

Glenn Adams <glenn@skynav.com> changed:

           What    |Removed                     |Added
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                 CC|                            |glenn@skynav.com

--- Comment #1 from Glenn Adams <glenn@skynav.com> ---
(In reply to comment #0)
> It appears that supporters of EME are not themselves intending to distribute
> premium content using the Clear Key key system. It appears that the main use
> of Clear Key by the supporters of EME is to use it for debugging.
> 
> Even if the Clear Key scheme might have utility for debugging, I think it
> shouldn't be a requirement to ship such debugging code. Moreover, an
> implementor may opt to debug the full stack instead using the sort of CDM
> that premium content would be targeted to but perhaps using debugging keys.
> 
> Moreover, it isn't a given that a non-Clear Key CDM always comes with an
> implementation of Clear Key and it doesn't really make sense to have to
> maintain an implementation of Clear Key on the production level of quality
> if its purpose is just debugging and the CDM or CDMs that are really
> intended for actual premium content don't happen to expose the Clear Key
> option. 
> 
> Furthermore, if one expects DRM for video to eventually go away as it did
> for audio, having Clear Key support shipped in release builds would for sure
> mean that some content would become dependent on it even if that content
> wouldn't actually gain any protection. Thus, if the owners of premium
> content one day no longer want DRM, we'd still have to keep EME machinery
> around for backwards compatibility with content that exercises Clear Key for
> no good reason.
> 
> Implementing Clear Key independently of the CDM implementation for another
> key system does not come for free: Browsers that outsource MP4 demuxing
> might have to implement their own MP4 demuxing where platform MP4 demuxing
> does not support Common Encryption. Thus, browsers that use platform
> decoders but don't have a CDM for another key system that would support
> Clear Key as a side effect might have to do useless development work just to
> get Clear Key working for sites that for whatever reason use Clear Key even
> though those sites are not gaining any actual protection by using it.

Since the ClearKey system is already specified in the ED, and since I'm not
aware of any intrinsic technical bugs reported against it (other than it might
not satisfy some use cases, which I don't view as a technical bug), then I
would prefer to see it remain in the ED. In other words, I see no harm in it
remaining in the ED. Removing it seems to entail non-zero editorial effort and
removes a useful defined CDM.

As for whether its support should be mandatory (MUST) or recommended (SHOULD),
I would not object to it being changed from MUST to SHOULD implement. Also, it
seems to me that a UA could conditionally support the org.w3.clearkey keySystem
according to content type. For example, MediaKeys.isTypeSupported("video/mp4",
"org.w3.clearkey") could return false given the scenario you describe above,
while it might return true for other MIME types.

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Received on Tuesday, 19 February 2013 23:02:33 UTC