Re: [codec] Fwd: New Version Notification for draft-terriberry-oggopus-00.txt

Gregory Maxwell <gmaxwell@juniper.net> Thu, 12 July 2012 01:18 UTC

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From: Gregory Maxwell <gmaxwell@juniper.net>
To: Ron <ron@debian.org>, "codec@ietf.org" <codec@ietf.org>
Date: Wed, 11 Jul 2012 18:16:41 -0700
Thread-Topic: [codec] Fwd: New Version Notification for draft-terriberry-oggopus-00.txt
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Subject: Re: [codec] Fwd: New Version Notification for draft-terriberry-oggopus-00.txt
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Ron [ron@debian.org] wrote:
> If we add a new mapping family, then we sort of have created a stream
> that is not really backward compatible with previously existing code.

Thats unavoidable.  Say I tell you now that mapping 3 is B-format.
None of your existing code would know that. It wouldn't be able to
play it.  Not playing it is the right thing to do. rather than sending
W out the left speaker and Z out the right and what have you.

Other than perhaps adding more channels in the mapping 1
sequence (e.g. for counts > 8) I would not generally expect
other new mappings to actually be usefully compatible without
actually knowing what they were.

> One alternative is we could just revise the spec to define new families
> without bumping the minor version.  Since they'd basically act as you
>suggest for things that don't recognise them anyway in that case.
[snip]
> I likewise don't actually expect we will ever find a reason to bump
> the minor version 

Nah, thats the reason they're reserved.  You can think of it is though
they are all _already_ defined, but the devilish fog of causality
prevents you from seeing the definitions as of yet, and thus
you can't implement support for them.