[ogg-dev] handling multitrack Ogg

Silvia Pfeiffer silvia at silvia-pfeiffer.de
Wed Feb 3 21:49:49 PST 2010


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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