Re: [rtcweb] Proposed Video Selection Process

Silvia Pfeiffer <silviapfeiffer1@gmail.com> Fri, 22 November 2013 16:24 UTC

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References: <7949EED078736C4881C92F656DC6F6C130EA8AD7DD@ausmsex00.austin.kmvtechnologies.com> <528F30C1.8040208@it.aoyama.ac.jp>
Date: Fri, 22 Nov 2013 08:24:15 -0800
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From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
To: =?ISO-8859-1?Q?Martin_J=2E_D=FCrst?= <duerst@it.aoyama.ac.jp>
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Cc: rtcweb@ietf.org
Subject: Re: [rtcweb] Proposed Video Selection Process
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I think this has value. It might bring apple and Microsoft to the table,
since decoding-only is often the less patent-affecting part.

Silvia.
On 22 Nov 2013 02:24, Martin J. Dürst <duerst@it.aoyama.ac.jp>; wrote:

> On 2013/11/22 5:02, Stefan Slivinski wrote:
>
>> I in no way intended to suggest  a specific implementation of a video
>> codec.  My question was around whether we are voting on requiring decoders
>> (my assumption) or both encoders and decoders
>>
>
> My understanding is that all the proposals in each instance mean "both
> encoder and decoder". So as an example, a proposal of "MUST implement both
> VP8 and H.264" means "MUST implement both VP8 encoder and decoder, and
> H.264 encoder and decoder".
>
> Your question brings up other choices. For example, interoperability would
> be satisfied by something like "MUST implement both VP8 and H.264 decoders,
> and MUST implement at least one of VP8 and H.264 encoders".
>
> One condition for this to work is the possibility of asymmetric
> communication, i.e. if side A implemented only a VP8 encoder, and side B
> only implemented a H.264 encoder, then traffic A->B would be VP8, whereas
> traffic B->A would be H.264. I don't know the in's and out's of the
> negotiation and protocol machinery to confirm or deny that this is possible.
>
> Choices like the one above definitely open new horizons for Eric's
> selection generator. But frankly speaking, except for the specific choice
> of "MUST implement both VP8 and H.264 decoders, and MUST implement at least
> one of VP8 and H.264 encoders", which is less onerous than "MUST implement
> both VP8 and H.264", but still interoperable, I don't see any choices with
> different requirements for encoders and decoders that would make sense.
>
> Regards,   Martin.
>
>
>  ----- Original Message -----
>> From: Basil Mohamed Gohar [mailto:basilgohar@librevideo.org]
>> Sent: Thursday, November 21, 2013 01:56 PM
>> To: rtcweb@ietf.org<rtcweb@ietf.org>
>> Subject: Re: [rtcweb] Proposed Video Selection Process
>>
>> On 11/21/2013 02:31 PM, Stefan Slivinski wrote:
>>
>>> I'm a new comer, so just a brief intro: I have a background developing
>>> real time video codecs for embedded devices so I'm in a position to comment
>>> at a technical level within this group
>>>
>>> For clarity purposes the proposed alternatives in Magnus' email on nov
>>> 18th; are we strictly speaking about decoders?  Historically mandatory
>>> requirements are they relate to video compatibility define just the
>>> decoders.  Obviously if there is only a single mandatory video decoder this
>>> implies a mandatory encoder, however in the case where there are 2
>>> mandatory decoders only a single encoder is technically required.
>>>
>>> Clarifying this is fairly important because in the case of both h264 and
>>> vp8 (and in the future vp9 and h265) the decoder complexity is fairly low
>>> and hardware acceleration is not critical but in the case of the encoders
>>> where the complexity can be 3x or worse, hardware acceleration becomes
>>> increasingly important
>>>
>>> Stefan
>>>
>>
>> What is being specified as MTI is a format, and not a specific
>> implementation.  So, MTI will not take the form of "OpenH264" or
>> "libvpx", but rather, "H.264 Constrainted Baseline Profile" or "VP8".
>>
>> The same was done for the MTI audio codec, which is Opus, not *libopus*,
>> which is one specific implementation of the codec.
>>
>> There was a suggestion that the WG also offer a reference implementation
>> of the MTI codec choice, but that seems like it won't happen, nor is it
>> really the purpose of the WG to do so.  We are picking from
>> already-existing and implemented formats in the first place.
>>
>>  _______________________________________________
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