Re: [rtcweb] Is there room for a compromise? what about no MTI?

tim panton <tim@phonefromhere.com> Tue, 14 January 2014 20:56 UTC

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From: tim panton <tim@phonefromhere.com>
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References: <CABcZeBNx5wpKDgd6TgA9U3_nxEKXdCsXpo8Kp663yQ6e_iN9vQ@mail.gmail.com> <20131215075757.GB3245@audi.shelbyville.oz> <52AE54F8.5070300@bbs.darktech.org> <CABcZeBNqE25O+BNLboXDrJ1ypp26uRAw8ehwtyor9gJccpuzGw@mail.gmail.com> <52AE759C.7020209@bbs.darktech.org> <CABcZeBMjTGs41t7y=xvaLdn4i63HxC2YQUkrd-itq=VkuKvpTA@mail.gmail.com> <52AE9129.8090702@bbs.darktech.org> <CABcZeBPOxqa2YQxOrTp9sVF-tQrpg-Kn=CbazBXOx_9dajhUZA@mail.gmail.com> <52AE9E0C.9060707@bbs.darktech.org> <20131216170820.GD82971@verdi> <20131220113631.GA70585@verdi> <52B47196.6060400@bbs.darktech.org> <D5B39658-5766-4C5B-9090-8E8EDC4BCFA6@apple.com> <52B484AB.5020102@bbs.darktech.org> <CAOJ7v-0QcMsZ+nxG+kP99zE-+VUiFesGh05agwsnmaMCapJSmA@mail.gmail.com> <52B4B85F.2070209@dcrocker.net> <CAOJ7v-21zRcW=mRdec+92qNikUFZNi_UqHqvFpOfC7-MAjvY=w@mail.gmail.com> <52B73B81.6050400@dcrocker.net> <CABcZeBM8P==y_tXrNp-Rxe5unXyJJatY-ONbhCfkGPwi0bCQBg@mail.gmail.com>
To: Eric Rescorla <ekr@rtfm.com>
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Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>, Dave Crocker <dcrocker@bbiw.net>
Subject: Re: [rtcweb] Is there room for a compromise? what about no MTI?
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Date: Tue, 14 Jan 2014 20:56:17 -0000
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On 22 Dec 2013, at 22:28, Eric Rescorla <ekr@rtfm.com> wrote:
> 
> 
> To take a simple example, a number of phones do not have front-facing
> cameras and also have processors that are incapable of doing an
> adequate video call (especially if we select a codec for which they
> don't have adequate hardware support). In that case, it might be
> reasonable to simply not offer video at all on such devices.  In such
> a case, would it really make sense to call such devices non-compliant
> for not implementing an MTI video codec that they wouldn't negotiate
> in any case?

That’s a whole set of assumptions that the browser vendor is loading on very little data.

- So just because there is no forward facing camera we assume there will be no possible webRTC
video usage ? - I disagree - it may not do for the classic f2f call, but I’ve seen plenty of show-and tell
use cases where the rear cam is the one sending video.

As for the incapable hardware example, again there are plenty of 1 way video call cases 
(think amazon mayday), the hardware may be able to decode something it can’t encode.

As I noted a while back SDP OA is clumsy at expressing these asymmetrical nuances, but I’ve
been assured it is possible.

Also I notice that the Raspberry Pi which has h264 in silicon has recently started supporting VP8
by using the GPU to accelerate some of the encode operations. - An example a device that seems not
to support a given codec, but with a firmware upgrade can.

It would be a shame if (for example) firefox on the Pi didn’t offer webRTC video just because at some
point one of the devs had had a Pi with no camera module or where VP8 was too slow.

;tldr
- We need to leave these decisions to app developers and not assume anything we don’t absolutely have to.



Tim.