[theora-dev] First steps towards a simple text stream format.

Arc arc at indymedia.org
Fri Aug 22 00:36:43 PDT 2003

On Fri, Aug 22, 2003 at 04:53:44PM +1000, Silvia.Pfeiffer at csiro.au wrote:
> >Indeed, the use of CMML is overhead in my view -- overhead for a
> >subtitle format, but not necessarily overhead for the other things
> >annodex does. As I've indicated, the fact that annodex wraps around all
> >other streams is what I have the most difficulties accepting. Do you
> >mean that annodex doesn't enforce this, and that I could use only the
> >annotation stream of annodex, or is this violating the spec?
> When you use only the annotation stream, it's not an annodex file any 
> longer. Feel free to try that out though.

Already have, Philip and I (along with quite a few others, Rillian,
purple, derf, monty, etc) have developed a "text" stream format that can
be used for closed captions and subtitles called Ogg Writ.

Implementing it, however, has lead to some interesting developments with
libogg2, such as the need to expand the Ogg specification to allow for
discontinuous bitstreams (granulepos = start time, CONT pages must
immediatly follow the previous in the physical bitstream, etc) and
things that OggFile will have to include in order to support these

Very low overhead, easy to implement, libxml not needed.  Does text,
it's suggested location and alignment, start time and duration, does not
do fonts colors sizes styles or hyperlinks.

Development of libwrit is "on hold" until Monty finishes up some work
with libogg2, but a reference encoder/decoder has already been written
in python and hand-verified with a hex editor to match the current spec.
We should be able to get support for it in the early stages of OggFile,
and thus in the initial beta Theora software for public use.

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