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Re: Media Source draft proposal

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Fri, 20 Apr 2012 13:33:05 +1000
Message-ID: <CAHp8n2ndp_Kp2jAvaJc=jTYuj38bckaAq_AYCOScV-bMr2BmEg@mail.gmail.com>
To: Maciej Stachowiak <mjs@apple.com>
Cc: robert@ocallahan.org, Aaron Colwell <acolwell@google.com>, public-html@w3.org, Adrian Bateman <adrianba@microsoft.com>, Mark Watson <watsonm@netflix.com>
On Fri, Apr 20, 2012 at 1:19 PM, Maciej Stachowiak <mjs@apple.com> wrote:
>
> On Apr 19, 2012, at 4:45 PM, Robert O'Callahan wrote:
>
> On Fri, Apr 20, 2012 at 6:58 AM, Maciej Stachowiak <mjs@apple.com> wrote:
>>
>> It seems to me that this spec has some conceptual overlap with WebRTC, and
>> WebAudio, which both involve some direct manipulation and streaming of media
>> data.
>>
>> WebRTC: http://dev.w3.org/2011/webrtc/editor/webrtc.html
>> Web Audio API:
>> https://dvcs.w3.org/hg/audio/raw-file/tip/webaudio/specification.html
>
>
>
> I actually think those are fairly well separated from this proposal. This
> proposal is all about manipulating the data that goes into a decoder; WebRTC
> and the Audio WG are all about manipulating decoded data. The latter two
> need to be carefully coordinated, but this doesn't.
>
>
> From what I can tell, it's not the case that WebRTC manipulates only decoded
> data.Twp examples: PeerConnection lets you send a MediaStream to a remote
> peer and receive a MediaStream from remote peer. Surely it is not the case
> that media data sent over PeerConnection is always decoded? It seems obvious
> that such data would have to be encoded at least in transit. Likewise, the
> getRecordedData method in WebRTC generates "a file that containing data in a
> *format supported by the user agent* for use in audio and video elements"
> (emphasis added), which is surely encoded data, not decoded data. In fact, I
> cannot find any case where the WebRTC spec offers any kind of access to
> decoded media data.
>
> It might be that there is a good reason why receiving a media stream over a
> peer-to-peer connection and then playing it via a video element should use a
> completely different API than receiving a stream from a server and then
> playing it via a video element. But if such a reason exists, it is not
> documented in either spec. It's definitely not about the difference between
> encoded vs decoded.


Could we agree on having the AV Encryption TF look at the encryption
proposal and regard all the other media-related specifications that
exist wrt what impact encryption has on them. That would include
proposing any necessary changes to those other proposals to the
respective groups that are working on them. However, the core of the
work on the other specifications is not done by the AV Encryption TF.

If we can't agree on this, if would be more logical to throw all media
related work into a task force and create a Media TF that would work
on all these issues and anything else that comes up around audio and
video.

Regards,
Silvia.
Received on Friday, 20 April 2012 03:33:57 GMT

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