W3C home > Mailing lists > Public > public-media-annotation@w3.org > September 2010

OGG container

From: Thierry MICHEL <tmichel@w3.org>
Date: Tue, 21 Sep 2010 12:28:52 +0200
Message-ID: <4C9888E4.8010305@w3.org>
To: "public-media-annotation@w3.org" <public-media-annotation@w3.org>

I have investigated into the OGG container to fill our OGG mapping table [1]

Ogg does not know anything about the content it carries and leaves it to 
the media mapping of each codec to declare and describe itself. There is 
no meta information available at the Ogg level about the content tracks 
encapsulated within an Ogg physical bitstream.


Ogg does not replicate codec-specific metadata into the mux layer in an 
attempt to make the mux and codec layer implementations 'fully 
separable'. Things like specific timebase, keyframing strategy, frame 
duration, etc, do not appear in the Ogg container. The mux layer is, 
instead, expected to query a codec through a centralized interface, left 
to the implementation, for this data when it is needed.

Though modern design wisdom usually prefers to predict all possible 
needs of current and future codecs then embed these dependencies and the 
required metadata into the container itself, this strategy increases 
container specification complexity, fragility, and rigidity.


Therfore I guess there is not much to fill in our OGG mapping table.


Received on Tuesday, 21 September 2010 10:29:16 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 16:24:43 UTC