[rtcweb] The importance of selecting a realistic mandatory video codec

Tim Panton <tim@phonefromhere.com> Sun, 01 April 2012 17:35 UTC

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From: Tim Panton <tim@phonefromhere.com>
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Date: Sun, 1 Apr 2012 18:35:40 +0100
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Subject: [rtcweb] The importance of selecting a realistic mandatory video codec
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In the ITEF 83 meeting I put forward the importance of a common video codec, "even if it is a grotty one".
What I tried to convey and may not have got over is that it needs to be a codec that all the browser
vendors will actually deliver, ideally in their first production releases of RTCweb.

Whilst a common codec is desirable for interop, it isn't essential, there can/will be transcoding proxies
which will paper over the differences and RTCweb can still succeed.

However if we see widespread use of transcoding, we will lose 2 of RTCweb's most exciting properties.

1) True P2P - i.e. the case where ICE can negotiate a direct connection behind a big NAT
2) security for calls over untrusted networks.

I am looking at use-cases for RTCweb where these are very important properties - think disaster relief for example,
without them RTCweb will be significantly harder to deploy over adhoc mesh wifis where the connection to the internet is very low bandwidth (if it exists at all) but where the meshed nodes can cover quite a big area with
decent, if variable, throughput.

For these cases it is essential we mandate a codec that will be delivered by _everyone_ . I don't care which it is.

The same arguments go for a mandated audio codec 
- with the additional requirements that it needs to be resilient to
packetloss (probably have FEC) and able to dynamically adjust bitrate to cope with the mesh changing topology.