ogg dev - May 2008 - How Ogg mappings translate into the codecs parameter in Ogg media types

On 5/24/08, Ralph Giles <giles at xiph.org> wrote:
> It's supposed to be finalized though there many be some granulepos
> issues still in current implementations. I don't expect the BBCD\0
> magic to change.
Great.
> OggMNG defines the following magics:
>
> char[8]: "\211PNG\r\n\032\n" png
> char[8]: "\212MNG\r\n\032\n" mng
> char[8]: "\213JNG\r\n\032\n" jng
Ah, yes, I had forgotten about image encapsulation!  Doesn't OggSpots
also cover standard JPEG?  Should we add it, too?
> Are the 'Codecs Parameter' values from a different namespace from
the
> media-types? Do we define a mapping where there is one, e.g. vorbis
> is audio/vorbis?
If I understand your question correctly, the answer is yes and no.  It
is part of the media types regardless of namespace, but it's just a
string to describe each contained codec not a specific media type like
what is used in Skeleton.

Here's an example: video/ogg; codecs="theora, vorbis, kate"
> And there's OggY4M which uses char[9]: "YUV4MPEG2" but
that's in no
> way finalized.
So this shouldn't be added, right?

-Ivo

On 24-May-08, at 10:07 AM, Ivo Emanuel Gon?alves wrote:
> Ah, yes, I had forgotten about image encapsulation!  Doesn't  
> OggSpots also cover standard JPEG?  Should we add it, too?
It does, but OggMNG does everything OggSpots does, so I don't think  
we should add it.
> So [YUV4MPEG] shouldn't be added, right?

Well, you've added OggPCM... :)

  -r

We have been asked to make a consistent table that explains at which
location in the stream we can find the correct string.
We will need to document all the bytes in use and maybe mark some with
a * where we don't care what's in it.
We should also by doing this prescribe to new codec mapping creators
how to best go about it.

I suggest we create a wiki page and put it all in there. Then we can
put the current version of the table into the RFC and refer to the
wiki page for the current updated version of the table.

Cheers,
Silvia.

On Sun, May 25, 2008 at 3:26 AM, Ralph Giles <giles at xiph.org>
wrote:
> On 24-May-08, at 10:07 AM, Ivo Emanuel Gon?alves wrote:
>
>> Ah, yes, I had forgotten about image encapsulation!  Doesn't
>> OggSpots also cover standard JPEG?  Should we add it, too?
>
> It does, but OggMNG does everything OggSpots does, so I don't think
> we should add it.
>
>> So [YUV4MPEG] shouldn't be added, right?
>
>
> Well, you've added OggPCM... :)
>
>  -r
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