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Re: EME support for CENC with AES-CBC?

From: Joe Steele <steele@adobe.com>
Date: Mon, 23 Jun 2014 16:06:44 +0000
To: Henri Sivonen <hsivonen@hsivonen.fi>
CC: "Jerry Smith (WINDOWS)" <jdsmith@microsoft.com>, David Dorwin <ddorwin@google.com>, Mark Watson <watsonm@netflix.com>, "<public-html-media@w3.org>" <public-html-media@w3.org>
Message-ID: <15CCF6B7-7186-45D7-A74D-207CFD8AEDAE@adobe.com>
My speculation about Apple being a possible supporter of this format is based on what Jerry alluded to, the usage of CBC in HLS. HLS v5 with AES-SAMPLE encryption is much closer to CENC than traditional HLS. Having said that  this was just speculation on my part. I have not looked at what the announced Apple CDM is doing yet. I would hope they support one of the two formats EME support today.

Joe Steele

On Jun 18, 2014, at 3:09 AM, Henri Sivonen <hsivonen@hsivonen.fi> wrote:

> On Tue, Jun 17, 2014 at 10:03 PM, Jerry Smith (WINDOWS)
> <jdsmith@microsoft.com> wrote:
>> I understand that CBC is used on HLS content, and there is a move to support
>> this for CENC.
> 
> But doesn't HLS use MPEG2-TS as the container instead of fragmented MP4?
> 
> If CBC in MP4 is different from whatever HLS is using precisely, what
> good does it do anyone to just adopt a block cipher mode from HLS?
> 
> As for the Apple CDM, is there a particular reason to believe that its
> non-CENCness is about the block cipher mode?
> 
> -- 
> Henri Sivonen
> hsivonen@hsivonen.fi
> https://hsivonen.fi/


Received on Monday, 23 June 2014 16:07:27 UTC

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