W3C home > Mailing lists > Public > public-html-media@w3.org > July 2012

答复: [Bug 17672] New: Define Initialization Data for implementations that choose to support the WebM Container

From: Sunyang (Eric) <eric.sun@huawei.com>
Date: Tue, 3 Jul 2012 08:48:38 +0000
To: "bugzilla@jessica.w3.org" <bugzilla@jessica.w3.org>, "public-html-media@w3.org" <public-html-media@w3.org>
Message-ID: <9254B5E6361B1648AFC00BA447E6E8C32AEB6694@szxeml545-mbx.china.huawei.com>
If the initialization data contains multiple keys, is that means one initData will trigger to setup multiple sessions?
So if we want to decode a file with multiple keys, I have to construct multiple MediaKeySession objects, it may be a little complex, can we have a umbrella concept for a media file to manipulate multiple keys scenario?

And it says the initData will contain encryption parameters, will that be common for all encryption algorithm?

发件人: bugzilla@jessica.w3.org [mailto:bugzilla@jessica.w3.org] 
发送时间: 2012年7月3日 7:39
收件人: public-html-media@w3.org
主题: [Bug 17672] New: Define Initialization Data for implementations that choose to support the WebM Container


           Summary: Define Initialization Data for implementations that
                    choose to support the WebM Container
           Product: HTML WG
           Version: unspecified
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P3
         Component: Encrypted Media Extensions
        AssignedTo: adrianba@microsoft.com
        ReportedBy: ddorwin@google.com
         QAContact: public-html-bugzilla@w3.org
                CC: mike@w3.org, public-html-media@w3.org

v0.1 of the proposal says "Initialization Data is... container-specific data" 
[1]. To help ensure implementations that choose to support a given format are
interoperable and provide examples for the reader, we should define
Initialization Data along with its use and behavior for common formats. This is
similar to how the Media Source proposal has provided guidance for containers

This bug tracks this task for the WebM Container [3].

Below is a non-exhaustive list of items to address:
* Files should specify encryption parameters per [4] or its successor.
* What are the contents of initData? Likely the key ID for the current Track.
* Such initData would result in a license containing a single key.
* A needkey event would be fired for each key encountered/needed.
* Are the contents of the needkey event fired when an encrypted block is
encountered and no key is available [5] the same as the initial needkey event?
* Are needkey events fired for each Track even if they use the same key in the
same file/stream/source?

Note: As currently written, the proposal would result in each key ID being a
separate session and possibly a separate object (bug 16613). This applies to
different keys for audio and video as well as more complex scenarios.



[3] http://www.webmproject.org/code/specs/container/

[4] http://wiki.webmproject.org/encryption/webm-encryption-rfc

Configure bugmail: https://www.w3.org/Bugs/Public/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.

Received on Tuesday, 3 July 2012 08:49:29 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 15:48:24 UTC