Re: Call for Consensus (CfC): WebRTC-NV "One-way media" Use Cases (Section 3.10))

> On 17 Jan 2023, at 21:30, Bernard Aboba <Bernard.Aboba@microsoft.com> wrote:
> 
> This is a Call for Consensus (CfC) on the WebRTC-NV "One-way media" Use Cases described in Section 3.10: 
> 
> 3.10.1     Live encoded non-WebRTC media

This use case seems like a potential optimization to remove the need to decode/encode the content at the RTCPeerConnection level.

It is also unclear whether there is an issue where the application could try to go largely above the available bandwidth.
This is something that would be useful to evaluate.

In terms of requirements:
- N40 is already feasible. It should probably be precised.
- N41 is not really a requirement but already an API proposal. It should probably be rewritten in a more agnostic way. The underlying requirement would probably be solved by an API that would directly send/receive RTP packets.
- N42 is already feasible via WebRTC stats. It should probably be precised.

> 3.10.2     Transmitting stored encoded media

The requirements for this use case are not complete enough.
In particular, there would be a need to handle PLI or FIR, which might not be possible to answer without either reencoding or having a stream with key frames only.

In addition, this use case seems already implementable with existing web APIs.
It would good to evaluate what the expected benefits are of this approach compared to solutions using existing web APIs.

> 3.10.3      Decoding pre-encoded media

This use case is mainly based on the assumption that JS based processing via WebCodecs is not optimal for speedy processing.
It would be good to have measurements to understand what perf improvements we are talking about.

Ditto for MSE, which is already able to support media-over-datachannel, DRM and file playback.

> 
> The use cases are available for inspection here: 
> https://w3c.github.io/webrtc-nv-use-cases/#one-way-media
> 
> The GitHub repo Issues list is here: Issues · w3c/webrtc-nv-use-cases (github.com) <https://github.com/w3c/webrtc-nv-use-cases/issues>
> 
> In response, please state one of the following: 
> I support addition of the "One-way  media" use cases
> I object to addition of the "One-way media" use cases, due to issues filed in <link to GitHub issues> 

I do not support these use cases in their current form.

There were past discussions where WebTransport was initially thought as a potential solution for similar use cases.
IIRC, it was said that WebTransport was not able to match all RTP based transport functionalities.
It would be good to further dive into this area and extract corresponding requirements.

In general, my hunch is that exposing an API to do direct RTP packet handling would be a better fit. 
Web applications could then either go with RTCPeerConnection, WebCodecs+WebTransport or WebCodecs+RTPTransport.


> The CfC will last until midnight Pacific Time on February 6, 2023. 
> 
> Bernard
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