Re: [rtcweb] Plan for MTI video codec?

[Justin Uberti <[e-mail]>]

Looks like someone wants to have not just one, but two MTI codec
discussions...

On Sun, Oct 19, 2014 at 6:20 PM, Cavigioli, Chris <[e-mail]
> wrote:

>  Harald said:
>
> “We made the mistake of having an MTI discussion previously with not
> enough details on that subject…”
>
>
>
> We didn’t have quantitative data earlier for a data-driven decision.
> Future Web – LTE interop is important.  A group of us in GSMA have been
> looking at WebRTC interop with LTE (where 3GPP / GSMA defined IMS-based
> voice/video/messaging), specifically looking at user experience impact of
> latency introduced by added in-network transcoding.  GSMA has approved the
> whitepaper and it is being prepared for public distribution.
>
>
>
> WebRTC – LTE transcoding is now MANDATORY because of “WebRTC Audio Codec
> and Processing Requirements”.
> http://tools.ietf.org/html/draft-ietf-rtcweb-audio-05, where MTI audio
> codecs in WebRTC and in LTE are dissimilar.  Thus, REGARDLESS of the video
> codecs, there is already a significant degradation imposed on Web – LTE
> links if only MTI codecs are used.  The only systems to avoid this are
> those which implement OPTIONAL audio codecs to be transcoder-free with
> LTE.  The same can apply for video codecs.
>
>
>
> The GSMA whitepaper refers to:
>
> 1.     Quantitative voice-over-LTE (VoLTE) delay limits were agreed-to by
> 3GPP SA4 in August 2014.  To paraphrase, performance objectives for maximum
> VoLTE device delays in error and jitter free conditions and AMR speech
> codec operation, the sum of the UE delays in sending and receiving
> directions (TS + TR) should be ≤ 150ms. If this performance objective
> cannot be met, the sum of the UE delays in sending and receiving directions
> (TS + TR) shall in any case be ≤ 190ms.
>
> 2.     OPUS – AMR transcoding adds an additional 211.5 ms
> implementation-agnostic (TS + TR) delay, including 40 ms for jitter
> buffer and 40 ms for discontinuous reception (DRX).
>
> 3.     To put these numbers in perspective, it is in general desirable to
> minimize UE delays to ensure low enough end-to-end delays and hence a good
> conversational experience.  Increasing delay causes people to double-talk
> making conversations increasingly frustrating.  Guidance to stay below 400
> ms maximum one-way delay is found in ITU-T Recommendation G.114 and the
> computational E-model is in ITU-T Recommendation G.107.
>
>
>
> This is a complex topic with many network factors in play.  LTE operators
> in 3GPP seek UE delays (TS + TR) around 150 ms.  Adding OPUS – AMR
> transcoding in the network imposes an additional 211.5 ms on top of that,
> just for audio.  Optionally using AMR in WebRTC, those 211.5 ms can be
> eliminated, delivering a superior end-user experience.
>
>
>
> CONCLUSION:  regardless of MTI codec choices in WebRTC, to provide a good
> WebRTC – LTE interop experience, emerging WebRTC systems must accommodate
> MTI codecs already deployed in the LTE domain and in mobile operating
> systems, namely AMR/AMR-WB and H.264.
>
>
>
> POSITION:  To be clear, several Intel SoCs launched at MWC this year for
> smartphones and tablets support both VP8 and H.264 hardware encode and
> decode – so Intel is codec-neutral in this MTI debate.  Additionally, Intel
> has high-performance solutions for transcoding.  However, we wish to inform
> the industry, with quantitative data, about impact to end-user experience
> of mandating such transcoding so IETF can make a data-driven decision on
> video codecs as well as reflect on the impact of already having mandated
> transcoding on the audio side.
>
>
>
> Chris Cavigioli
>
> Intel Corp, System Architecture and Planning, Video/Multimedia, Mobile
> and Communications Group (MCG)
>
> [phone] mobile
>
> [phone] desk
>
> [phone] fax
>
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>
>
>
> *From:* rtcweb [mailto:[e-mail]] *On Behalf Of *Bernard
> Aboba
> *Sent:* Sunday, October 19, 2014 2:29 PM
> *To:* Harald Alvestrand
> *Cc:* [e-mail]
> *Subject:* Re: [rtcweb] Plan for MTI video codec?
>
>
>
> Harald said:
>
>
>
> "Bernard,
>
>
> I think this is, to a large degree, codec independent.
>
> We have demonstrated interoperability on VP8 between Firefox and Chrome,
> and usage of various mechanisms for congestion control and repair of packet
> loss being applied in live services.
>
> So it can't be all bad....."
>
>
>
> [BA]  I agree that the lack of interoperability is largely "codec
> independent":   that is, implementations based on different mechanisms for
> congestion control, repair, etc. will exhibit interoperability problems,
> regardless of the codec chosen.   The real test for RTCWEB will be to move
> beyond "interoperability of implementations sharing source code"  to
> "interoperability of independent implementations, based on open standards".
>
>
>
>
> On Sun, Oct 19, 2014 at 1:38 PM, Harald Alvestrand <[e-mail]>
> wrote:
>
> On 10/19/2014 05:43 PM, Bernard Aboba wrote:
>
>  "And its one of the issues holding up wider adoption of the technology"
>
>
>
> [BA] Specifying an MTI encoder/decoder is not sufficient for
> interoperability.  It is also necessary to specify the transport in enough
> detail to allow independent implementations that interoperate well enough
> to be usable in a wide variety of scenarios, including wireless networks
> where loss is commonly experienced.
>
>
> Bernard,
>
> I think this is, to a large degree, codec independent.
>
> We have demonstrated interoperability on VP8 between Firefox and Chrome,
> and usage of various mechanisms for congestion control and repair of packet
> loss being applied in live services.
>
> So it can't be all bad.....
>
>
>
>
>
>
> We made the mistake of having an MTI discussion previously with not enough
> details on that subject, particularly with respect to H.264.
> draft-ietf-rtcweb-video sections 4.2 - 4.4 remain sketchy at best.
>
>
>
> So if we are to have the discussion again, it should occur in the context
> of detailed specifications and interoperability reports.
>
>
>
>
>
>
>
>
>
>
>
> On Sun, Oct 19, 2014 at 8:14 AM, Jonathan Rosenberg <[e-mail]>
> wrote:
>
> I'm in favor of taking another run at this.
>
>
>
> The working group has repeatedly said that an MTI codec is something we
> need to produce. And its one of the issues holding up wider adoption of the
> technology (not the only one for sure).
>
>
>
> And things have changed since the last meeting, a year ago now (November
> in Vancouver). Cisco's open264 plugin shipped and now just recently is
> integrated into Firefox. iOS8 shipped with APIs for H264. There are other
> things worth noting. Will this change the minds of everyone? Surely not.
> Will it sway enough for us to achieve rough consensus? Maybe. IMHO - worth
> finding out.
>
>
>
> On Sat, Oct 18, 2014 at 5:08 PM, Alexandre GOUAILLARD <
> [e-mail]> wrote:
>
> +1 to not having MTI codec discussion unless some progress has been made
> on VP8 at MPEG. Any news on that? I'm sharing harald's  feeling that there
> was no change on the members position.
>
>
>
> On Fri, Oct 17, 2014 at 9:22 PM, Harald Alvestrand <[e-mail]>
> wrote:
>
> On 10/17/2014 12:02 AM, Bernard Aboba wrote:
>
> One thing we could do instead of wasting time on MTI is to actually make
> progress on Sections 4.2 - 4.4 of draft-IETF-RTCWEB-video, so we could
> actually interoperate regardless of the codec.
>
>
> The big argument for an MTI is actually the one stated in -overview: It
> guards against interoperability failure.
>
> I would like to have an ecosystem where one can field a box, connect it to
> everything else, and run well for *some* level of "well" - and I would
> prefer that ecosystem to be one where it's possible to field the box
> without making prior arrangements with anyone about licenses.
>
> This argument hasn't changed one whit since last time we discussed it. And
> I don't see much movement on the specifics of the proposals either.
>
> We'll have to interoperate well with the codecs we field. So using some
> time to discuss draft-ietf-rtcweb-video seems to make sense. (And 4.1 isn't
> finished either. There's one sentence that needs to be removed.)
>
> I wouldn't say I'd be happy to not discuss this in Honolulu. But I'd
> prefer to re-discuss based on the knowledge that some significant players
> have actually changed their minds.
>
> At the moment, I don't see signs that any of the poll respondents have
> said "I have changed my mind".
>
> Harald
>
>
>
>
>
>  On Oct 16, 2014, at 2:28 PM, Martin Thomson <[e-mail]>
> wrote:
>
> On 16 October 2014 14:17, Matthew Kaufman <[e-mail]> wrote:
> And that's because something substantive has changed, or simply because
> wasting the WG time on this again is more entertaining than actually
> finishing a specification that can be independently implemented by all
> browser vendors? (A specification that we are nowhere near having, as far
> as
> I can tell)
>
> Personally, I've found the reprieve from this fight refreshing.  And
> it would appear that we've made some real progress as a result.  I'd
> suggest that if we don't have new information, we continue to spend
> our time productively.  If we can't find topics to occupy our meeting
> agenda time, then maybe we can free an agenda slot.
>
> _______________________________________________
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>
> _______________________________________________
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> https://www.ietf.org/mailman/listinfo/rtcweb
>
>
> _______________________________________________
> rtcweb mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/rtcweb
>
>
>
>
>
> --
>
> Alex. Gouaillard, PhD, PhD, MBA
>
>
> ------------------------------------------------------------------------------------
>
> CTO - Temasys Communications, S'pore / Mountain View
>
> President - CoSMo Software, Cambridge, MA
>
>
> ------------------------------------------------------------------------------------
>
> sg.linkedin.com/agouaillard
>
> ·
>
>
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>
>
>
>
>
> --
>
> Jonathan Rosenberg, Ph.D.
> [e-mail]
> http://www.jdrosen.net
>
>
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>
>
>
>
>
> _______________________________________________
>
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>
> [e-mail]
>
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>
>
>
> --
>
> Surveillance is pervasive. Go Dark.
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