[theora-dev] [ogg-dev] handling multitrack Ogg

[Silvia Pfeiffer]

On Wed, Feb 3, 2010 at 5:07 AM, Frank Barchard <fbarchard at google.com> wrote:
> It sounds like you're on the right track.  There are 2 places I would start
> looking - DVD's, and Quicktime.
> Quicktime is mature and the container is the basis for mp4 and 3gp.

That's what the post referred to - how it was done in QuickTime.

> Can you find a way to transcode to Ogg maintaining the track information?

Part of the result of putting such information into Skeleton will be
that such transcoding will be enabled, yes.

> As someone who makes videos, its beyond me to translate audio to other
> languages, but I would be interested in doing commentary tracks.  Right now
> I do a second version of the video for that.
> A nice feature in iMovie is that it does 'ducking', so the commentary pushes
> the audio levels of other tracks down as needed.

Yup, that's what editors are supposed to do. Hopefully some of the
open source editors will eventually evolve to contain such
functionality.


> Re
> if (video.tracks[1].lang == "fr")          video.tracks[1].enabled = true;
> It would help for W3C to standardize language codes.  Quicktime uses 3
> characters, Ogg uses 2 characters?
> There are also variations of the same language.  Can a script find a closest
> match?

There are standards for language codes. They are not all 2 characters long.
http://www.w3.org/TR/REC-html40/struct/dirlang.html explains what is
in use in W3C.


> In addition to scripting, a system level setting could be used to select
> preferred tracks.

Indeed, at least a browser preference setting would be nice. This is a
call that the browser vendors have to make, not us.


> What ever you do, should equally apply to subtitles.

Of course. This was just an example. We are also talking textual audio
descriptions, btw.

Cheers,
Silvia.