Re: [rtcweb] H.261

Hrishikesh Kulkarni <rishi@turtleyogi.com> Wed, 27 November 2013 06:39 UTC

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References: <CEB4350B.1E7B2%mzanaty@cisco.com> <CEB43444.4986F%stevek@stevek.com> <CAMwTW+jO-BQh00fmH-ueCNsVsHbHRCiwHt6X0jFbho-B89ag=Q@mail.gmail.com> <CAOJ7v-0fwSrsT4CmTUP8cK7TJTA3J7LqDN0bbtNT4DxnQS6HnQ@mail.gmail.com>
Date: Wed, 27 Nov 2013 12:09:09 +0530
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From: Hrishikesh Kulkarni <rishi@turtleyogi.com>
To: Justin Uberti <juberti@google.com>
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Subject: Re: [rtcweb] H.261
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On Fri, Nov 22, 2013 at 10:23 PM, Justin Uberti <juberti@google.com> wrote:

> For 1:many with MCU, I don't understand why you wouldn't do #2, i.e.
> transcode. As stated earlier, the bandwidth costs of using an inefficient
> codec (which any MCU service will incur) exceed the CPU cost of transcode.
>

Good point on bandwidth costs. But you need to transcode if the decoding
endpoints/browsers dont support the codec or the bitrate of the source.
This applies to audio and video. If the source video is 720p@800kbps which
could then "transrated" into multiple bitrates at 500kbps or downsized to
480p@300kbps. We did this for audio when Chrome was on isac and Firefox was
on opus.


>
>
> On Fri, Nov 22, 2013 at 4:47 AM, <bryandonnovan@gmail.com> wrote:
>
>> Lots of uses will be 1:1 calls, and maybe 30% fallback applies in this
>> case.  My use of WebRTC involves 1:many group calls in the browser with an
>> MCU.  For 1:many, the options are 1) fallback to common codec and 2)
>> transcode.  So, for 1:many we can say that the chance of using the fallback
>> codec is 100%.  Assuming IE and Safari actually ship WebRTC.
>>
>>
>>
>> On Thu, Nov 21, 2013 at 10:11 PM, Steve Kann <stevek@stevek.com> wrote:
>>
>>>
>>> Mo,
>>>
>>> I think we all agree that choosing H.264 or VP8 would be better, but it
>>> is clear that neither option today has consensus.    Circumstances could
>>> change in the future, but it seems that OpenH264 was not enough to change
>>> that circumstance.
>>>
>>> I think that where your scenario might go astray is that users won’t
>>> associate their poor experience with “WebRTC”, or “that web stuff” — they
>>> will associate it with the brand of the service which they are using at the
>>> time.
>>>
>>> So, for example, if Facebook builds video chat using WebRTC, and they do
>>> no transcoding, 30% of users might associate their poor video with
>>> Facebook, but most of them won’t call it “that web shit” — they would say
>>> Facebook video sucks.
>>>
>>> Of course, Facebook could decide to transcode 30% of the time, in which
>>> case the user would have a different experience.
>>>
>>> Facebook obviously just being used as an example service which might
>>> implement WebRTC video.
>>>
>>> -SteveK
>>>
>>>
>>>
>>> From: "Mo Zanaty (mzanaty)" <mzanaty@cisco.com>
>>> Date: Thursday, November 21, 2013 at 9:17 PM
>>> To: Basil Mohamed Gohar <basilgohar@librevideo.org>
>>> Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>
>>> Subject: [rtcweb] H.261
>>>
>>> On 11/21/13 12:48, Basil Mohamed Gohar <basilgohar@librevideo.org>
>>> wrote:
>>>
>>> Has anyone actually objected to H.261 being the one MTI codec [...] ?
>>>
>>>
>>> Assume this wins and all obey. Chrome does H.261+VP8, Firefox does
>>> H.261+H.264+VP8, IE does H.261+H.264, Safari does H.261+H.264. According to
>>> various (incredibly extrapolated, possibly inaccurate and sometimes
>>> conflicting) sources [1] on who uses what browser, the chance of H.261
>>> fallback is a whopping 30% [2]. Not the minor insignificant case some had
>>> assumed.
>>>
>>> How will these users react to H.261 QCIF/CIF compared to what they use
>>> today, say Skype for example? "This web shit really sucks. I’m going back
>>> to Skype and never trying it again." Is that the first (and perhaps last)
>>> impression we want from users that try webrtc? Those arguing crappy video
>>> is better than no video are ignoring the critical importance of first
>>> impressions. While some may accept crappy video as usable, many more may be
>>> permanently turned off and tune out even faster than if they got only
>>> (good) audio. It’s not as if webrtc is the only game in town. Users have
>>> options, so it needs to be competitive with competitive technology which
>>> has already set the bar.
>>>
>>> We previously narrowed the options down to H.264 and VP8 for good
>>> reasons over the course of this excruciatingly long decision. Reopening
>>> discarded tangents like H.261 does not move us forward as a workgroup, and
>>> certainly does not move webrtc forward as a technology.
>>>
>>> Mo
>>>
>>> [1] http://en.wikipedia.org/wiki/Usage_share_of_web_browsers
>>> [2] H.261 fallback % = 2 x VP8-only% x H.264-only% = 2 x Chrome% x (IE%
>>> + Safari%)
>>>
>>> _______________________________________________ rtcweb mailing list
>>> rtcweb@ietf.org https://www.ietf.org/mailman/listinfo/rtcweb
>>>
>>>
>>> _______________________________________________
>>> rtcweb mailing list
>>> rtcweb@ietf.org
>>> https://www.ietf.org/mailman/listinfo/rtcweb
>>>
>>>
>>
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>>
>
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