[ogg-dev] handling multitrack Ogg

Frank Barchard fbarchard at google.com
Thu Feb 4 05:12:38 PST 2010


DVD has the UI and the low level meta information.
The API you propose is the glue between the 2.
It also has practical content.

Could a DVD like UI be implemented on top of your API?
It may need more exploration features?

Could your API be used on DVD content asis?  Do your APIs have 1:1
relationship with meta information in the files?
multiple languages requires language codes match up.  Your example shows
exact matches, but there are multiple versions of each language.
role/type is tricky.  commentary tracks on a movie may be different speakers
in the same language.  Does your API match what the underlying file formats
expose?

As far as I know, basic transcodes to ogg and mp4, dont translate language
codes, and dont maintain type and role meta information?

On Wed, Feb 3, 2010 at 9:49 PM, Silvia Pfeiffer
<silvia at silvia-pfeiffer.de>wrote:

> What would the creation of a AVI or MPG with 2 audio tracks tell me
> that I don't know yet? I can just use normal ffmpeg for that - ffmpegx
> is just a GUI transcoding tool based on ffmpeg and the latest ffmpegx
> release is more than 2 years old.
>
> Anyway, I did look at the AVI spec after this email
> (http://msdn.microsoft.com/en-us/library/dd318183%28VS.85%29.aspx) and
> found that while each track has a type and a language, there is no
> track numbering and there are no track identifiers.
> But I have found a track priority, which allows ordering the tracks,
> though I didn't find a single AVI file with nonzero wPriority.
>
> Cheers,
> Silvia.
>
>
>
> On Thu, Feb 4, 2010 at 6:57 AM, Frank Barchard <fbarchard at google.com>
> wrote:
> > On Mac the ffmpegx tool supports 2 audio tracks.  Maybe worth checking
> out?
> > http://www.ffmpegx.com/index.html
> >
> > Creates AVI or MPG files with two audio tracks.
> > Supports subtitles in VobSub, SubRip, MicroDVD, SubViewer, Sami, VPlayer,
> > RT, SSA, AQTitle, JACOsub and MPsubt formats
> >
> > On Tue, Feb 2, 2010 at 5:40 PM, Silvia Pfeiffer <
> silvia at silvia-pfeiffer.de>
> > wrote:
> >>
> >> On Wed, Feb 3, 2010 at 11:21 AM, Chris Double <
> chris.double at double.co.nz>
> >> wrote:
> >> > Excerpts from Frank Barchard's message of Wed Feb 03 13:11:15 +1300
> >> > 2010:
> >> >>
> >> >> Yes, and its good to learn from DVD's too.
> >>
> >> DVD is a subpart of MPEG: http://www.mpucoder.com/DVD/vobov.html,
> >> http://dvd.sourceforge.net/dvdinfo/dvdmpeg.html .
> >> Uses the same functionality for tracks, iiuc.
> >>
> >> > It might be useful to look at the Matroska container format too. It
> >> > handle's multiple tracks iirc.
> >>
> >> Matroska is interesting, see
> >> http://www.matroska.org/technical/specs/index.html#Track .
> >>
> >> It has a TrackNumber and a TrackUID (the latter probably maps well
> >> onto Ogg serialnumbers) and a Name (human-readable).
> >>
> >> Further for display order it has a TrackOverlay element, which
> >> specifies a track to be an overlay onto another one.
> >>
> >> Cheers,
> >> Silvia.
> >> _______________________________________________
> >> ogg-dev mailing list
> >> ogg-dev at xiph.org
> >> http://lists.xiph.org/mailman/listinfo/ogg-dev
> >
> >
>
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