> On 30 Jun 2015, at 12:49, Julien Isorce <[email protected]> wrote:
> 
> Hi,
> 
> I am not sure if clearkey allow you to access the raw video data after 
> decryption and decoding.

I don’t think clear-key has strong requirements in that regard. It’s not meant 
to be used for real deployments, as far as I know.

> If not you I know only 2 solutions:
> 
> - decoder and renderer can be setup to support DRM. I think a such setup can 
> only happen at driver level. And ideally CPU should not be able to access 
> this raw data.
> In the case of HW decoder and GL driver it will prevent to download the 
> gltexture. For ex: you get a blackframe, same if you try to read back the 
> content of the framebuffer.
> It will allow to safely manipulate gltexture ids in webkit compositing engine.
> I do not know if there are such existing GPU drivers. I remember seeing some 
> DRM structure members in openmax platform specific headers on Raspberry-Pi 
> but not sure if this is related and/or usable.
> 
> - if the platform does not support DRM, it should fallback to video hole 
> punching. A third-party will have to provide a gst element that implements 
> these GStreamer DRM interfaces/meta. DRM support in GStreamer should be such 
> that it allows to do that :) In that maybe we can revive this patch: 
> https://bugs.webkit.org/show_bug.cgi?id=141560 
> <https://bugs.webkit.org/show_bug.cgi?id=141560>
> 
> I am not sure how CDM comes into the game but I guess this is the API that 
> will connect EME javascript API to the gstreamer media player.
> 

Yes, the CDM would request decryption keys and pass them to the decryptor, 
using an OOB event, for instance.

> What will be the sink and src caps for this GStreamer ClearKey decryptor ?
> 

application/x-cenc, original-media-type=(string)video/x-h264, 
protection-system=(string)58147ec8-0423-4659-92e6-f52c5ce8c3cc

and video/x-h264

Same with audio/mpeg.


> As far as i know video hole punching is the technique used by chromium to 
> support EME (I think video hole has been introduced in chromium in the first 
> place to have EME on Android)
> 
> I really wonder how iOS does support/implement EME ? (hole or driver)
> 

Maybe ask in webkit-dev :)

Philippe

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