To add some more information to this thread: * Ogg allows multiplexing of any number of audio, video, timed text (subtitle, annotation, karaoke) etc tracks (also called: logical bitstreams) together in one Ogg physical bitstream
* Skeleton is a header that marks for such a complex Ogg physical bitstream what logical bitstreams are actually inside the file: http://xiph.org/ogg/doc/skeleton.html * also, at the last FOMS workshop we defined ROE- http://wiki.xiph.org/index.php/ROE - a rich way to describe the relationships between the different logical bitstreams; it would help a player decide what to play back and how; the only implementation of ROE is so far in Metavidwiki, e.g. if you click the little caterpillar image at the top right at http://metavid.ucsc.edu/wiki/index.php/Stream:Screen_cast_march_08 (http://metavid.ucsc.edu/wiki/index.php?title=Special:MvExportStream&feed_format=roe&stream_name=Screen_cast_march_08&t=0:00:00/0:14:45). Full ROE spec as it currently stands is here: http://svn.annodex.net/standards/roe/roe_1_0.xsd As for trying to adjust volumes on the different tracks (as per the original request) all you really need is an application that can separately control for a multi-track Ogg audio file the volumes on the different tracks (the multitrack Ogg file should come with a skeleton). If you wanted to store the volume changes back to a file and re-play, you have several choices. You could extend ROE with a means to describe the volume changes, or you could define a new annotation track that would describe the volume changes of the different skeleton tracks, or you could add the volume changes to the meta headers of a CMML track (see http://www.annodex.net/TR/draft-pfeiffer-cmml-03.html), or you could re-encode the audio tracks at the changed volumes, and there's probably a number more that I haven't considered yet. What's the best option? To be honest, I don't know - that depends on your goals and how you want to implement the application. BTW: you could try and play around with gstreamer and filters on the different tracks of a multi-track Ogg file to get track-level volume changes happening. That would probably already provide what your need for the playback part of it. Cheers, Silvia. On Mon, Aug 18, 2008 at 10:25 PM, Gregory Maxwell <[EMAIL PROTECTED]> wrote: > On Mon, Aug 18, 2008 at 6:36 AM, Danny Piccirillo > <[EMAIL PROTECTED]> wrote: >> Sorry, but i wasn't sure the best place to post this. I was looking for some >> forums but it doesn't look like Xiph has any official ones. Anyways, i heard >> about this MT9 think a while ago and i thought it would be awesome if FLAC, >> Vorbis, and all could implement something like this. >> >> http://www.guardian.co.uk/music/2008/may/27/news.seanmichaels >> http://en.wikipedia.org/wiki/MT9 >> >> In combination with that, it would also be cool to have some sort of >> subtitles-esque thing for audio which would be useful for speeches and >> karaoke. >> >> These two things would be a very very big boost for free audio formats :) >> >> How feasible is this in the long run? > > Vorbis supports 255 channels in a single stream, FLAC 8. Ogg would let > you encapsulate many streams in one file, even combining Vorbis, FLAC, > and Speex. The open questions are application support and metadata > for signaling the right default settings. > _______________________________________________ > ogg-dev mailing list > [EMAIL PROTECTED] > http://lists.xiph.org/mailman/listinfo/ogg-dev > _______________________________________________ Flac mailing list [email protected] http://lists.xiph.org/mailman/listinfo/flac
