Re: EME support for CENC with AES-CBC?

I think this is a bridge to cross when we have a CDM that plans to support
the new encryption mode. Seems like a prime candidate for the
"capabilities" field proposed for isTypeSupported and that it could be
addressed by defining a capability value in the byte stream format
specification at some later date.

[Btw, we should probably define a high level format for the capability
field so that it is possible to mix standardized capabilities with
keysystem-specific ones].

...Mark


On Mon, Jun 16, 2014 at 6:03 PM, David Dorwin <ddorwin@google.com> wrote:

> Are you specifically interested in just CBC or is there something else in
> the amendment? (For what it's worth, it does not appear that amendment has
> been published.)
>
> The ISO Common Encryption EME Stream Format and Initialization Data
> <https://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/cenc-format.html#stream-format> spec
> is based on ISO/IEC 23001-7:2012 the AES-128 CTR encryption it specifies.
>
>
>
> On Mon, Jun 16, 2014 at 5:20 PM, Jerry Smith (WINDOWS) <
> jdsmith@microsoft.com> wrote:
>
>> It would seem that when new encryption types are added to CENC, then
>> these will need to be supported by CENC compatible CDMs.  If we agree on
>> that, then the current model for IsTypeSupported() should be sufficient.
>>
>> Jerry
>>
>> -----Original Message-----
>> From: Joe Steele [mailto:steele@adobe.com]
>> Sent: Monday, June 16, 2014 1:57 PM
>> To: <public-html-media@w3.org>
>> Subject: EME support for CENC with AES-CBC?
>>
>> I am curious whether this group intends to say anything about support for
>> the AES-CBC encryption mode for ISOBMFF with CENC. I have been reviewing
>> the amendments to the CENC spec, specifically "Part 7: Common encryption
>> format for ISO base media file format, AMENDMENT 1: AES-CBC-128 and key
>> rotation". I am wondering how CDMs should expect to handle this - or if it
>> is called out via isTypeSupported().
>>
>> This may have been discussed and I just cannot find the references to it.
>>
>> Joe
>>
>>
>