[Matroska-devel] FFV1/MKV IETF Session followup

Steve Lhomme slhomme at matroska.org
Sat Jul 25 06:48:59 CEST 2015


On Fri, Jul 24, 2015 at 3:36 PM, Sebastian G. <bastik>
<bastik.public.mailinglist at gmx.de> wrote:
> 23.07.2015, 01:44 Dave Rice:
>> Hi all,
>
> Hello,
>
> if I have to summarize my reply it is 'subset'.
>
>> that develop the Matroska and FFV1 specifications should not simply
>> throw the specifications "over the wall" into IETF, but to move
>> specification development itself to an IETF context in a way that
>> brings our discussions currently in ffmpeg-devel and matroska-devel
>> and integrates them into an IETF context.
>
> I still wonder if the IETF welcomes it, anyway.

There's a good chance and it's worth trying. I presented Matroska once
at the W3C and it didn't gain much traction. WebM wasn't much at that
time and Opus not there yet. It would make sense now to do it at the
IETF level which deals with lower level stuff than the web.

>>> [...] Steve Lhome said that Matroska was designed for
>>> streaming in networks and that Opus could be stored in Matroska for
>>> streaming. Matroska is supported in Chrome, Firefox and MS Edge.
>
> Don't care that much about names, but it should be 'Lhomme' instead of
> 'Lhome'.

I misspelled it on the chat so they kept it.

> How does one play a Matroska file with Firefox? It supports WebM which
> is a subset of Matroska, but I am unable to play a Matroska file that
> contains an h.264 encoded video, which is supported by Firefox as well.

That's software restriction. From what I know they decided (and I
think Chrome too) to only deal wih WebM to avoid having to support all
possible codecs. At that time Mozilla was refusing H.264. Now that
they support it via GPU or Cisco, they should rethink their original
choice.

>>> Tessa said that although the specifications are already available
>>> and the work is complete, the specifications would benefit from the
>>> IETF review process.
>
> The specifications would probably benefit from any review process.

Contrary to popular belief, the format has been discussed and reviewed
a lot (although considered as vaporware by many at the time, so not
many people were actually involved). The specification text, not so
much. And that's needed.

>>> Ben Campbell asked if it was ok if IETF take
>>> over change control, and Tessa said that was understood. Ted Hardy
>>> said that the community would need to participate in the IETF or
>>> the effort would fail. Tessa said that she hoped the community and
>>> IETF would come together. Steve Lhome, an original author of
>>> Matroska, said he would continue to participate where ever the work
>>> was going to happen.
>
> What would 'take control' actually mean? Assuming Matroska v4 gets
> standardized, could a potential Matroska v5 be created without the IETF?

Not sure, but I think it may mean that discussions should happen at a
ML at the IETF, some IETF meetings will take decisions on the format.
I personally don't care where/how it happens as long as it's not
inconvenient. The existing format will not go away. As for the future,
we'll see if there is demand or not. There are a few things that could
be done better in Matroska and if in the end there's a derivative
format designed at the IETF, why not. Even if it breaks backward
compatibility. Bringing that new format means adding the old one
should be easy too.

> Speaking of subsets. The WebM Project takes Matroska and transforms it
> into something new (a subset), but Matroska stays what it is.
>
> Why doesn't PREFORMA use a subset of Matroska, which would be
> standardized on its own?

We'll see how the discussions go. There's a chance some features are
left out. But it's OK to make different RFCs as additions on top of
the core RFC.

> Best regards,
> Sebastian G. (bastik)
>
> p.s. I might not provide further input, today or tomorrow, depending on
> whenever I'm at my computer or not.
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-- 
Steve Lhomme
Matroska association Chairman


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