Re: [avtext] framemarking: add frame size info

(As an individual.)

In the latest version of simulcast the media distributor would need the RID values, not the PT values, but the idea is the same — it needs the SDP.

Note that if the media distributor doesn’t have information from the SDP it can’t reliably identify the frame marking header extension at all, since header extension IDs are negotiated. So I’m not sure how much benefit there is to putting the size in the header extension.

That said, if we envision a scenario where encoders might be frequently changing their video size (in response to available network bandwidth, or the like), it might be useful for encoders to be able to indicate the current size they’re encoding without needing to send updated SDP all the time.

On Aug 26, 2016, at 12:52 PM, Paul E. Jones <paulej@packetizer.com<mailto:paulej@packetizer.com>> wrote:

Miguel,

You make the assumption that the media distributor will not see the SDP, I suppose.  While certainly a valid model, I'll admit that I had personally assumed any media forwarding function would see the SDP (or at least be told the PT values and any relevant flow information similar to what RFC 6236 provides) and would thus know which PT values correspond to what video resolutions if simulcast is employed.

Paul

------ Original Message ------
From: "Miguel París Díaz" <mparisdiaz@gmail.com<mailto:mparisdiaz@gmail.com>>
To: avtext@ietf.org<mailto:avtext@ietf.org>
Sent: 8/25/2016 10:12:48 AM
Subject: [avtext] framemarking: add frame size info

Hello,
it would be great having frame size (width and height) info in the Frame Marking RTP header extension [1].

Why?
For example, in the case of using simulcast in an SFU, selecting the stream by the size would ease the application development and improve the experience of the users.
Application developers don't usually have deep knowledge about media like bitrate, etc., but they know which video size has to be rendered in the GUI, which may depend on the client where the app is running: a mobile, a PC with a 13"· screen, a PC with 27" screen, etc.

In this way and taking a videoconference app as example, if a participant select another participant to be rendered as main video, the app could ask the SFU to select the video quality that better matches to 800x600 size.

What do you think about this idea?

Thanks and best regards!!

Refs
[1] https://tools.ietf.org/html/draft-ietf-avtext-framemarking-02

--
Miguel París Díaz
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Computer/Software engineer.
Researcher and architect in http://www.kurento.org<http://www.kurento.org/>
http://twitter.com/mparisdiaz
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