[Vorbis-dev] Enhanced Podcasts with Ogg Vorbis (Chapter Marks)
Georg Holzmann
grh at mur.at
Fri Jan 6 02:25:06 PST 2012
Hello list!
Since it is more and more common these days to create enhanced podcasts
(= audio files with additional chapter markers [1]), I am searching for
an alternative to the currently used MP4 format.
ID3 also puplished an official standard for chapters [2], but nobody
seems to use and support it.
Now I am trying to get something similar with vorbis audio (and maybe an
additional container).
So far I am aware of the following possibilities:
1) Matroska Audio with Chapter Marks
Using the matroska container, it is possible to generate a matroska
audio file (mka) with included chapters (see [3] for the exact command).
PROS:
- many media players and some hardware players support matroska, see [4]
- with e.g. VLC (or foobar) you see chapters and are able to seek in the
audio file - very nice!
- android 4 should support matroska natively [5] (but I don't think that
it's possible to see the chapters ?)
CONS:
- many hardward players, which support ogg vorbis, are not able to play
mka files
- I found no app on android so far which can play mka files
2) OGM Container with Chapter Marks
Using the same chapter.txt file, I created an OGM container with ogg
vorbis audio:
$ ogmmerge -o output.ogm audio_track.ogg chapters.txt
This seems to work, at least ogmmerge says so on the command line:
+-> Using Vorbis audio output module for stream 1.
Using chapter information reader for chapters.txt. working... -
PROBLEMS:
- I could not find any player which is able to show the chapters
- many players don't support ogm (winamp, foobar, ... - maybe with plugins)
- hardward players don't support ogm, also android has no ogm support AFAIK
So maybe I did something wrong here? Or does anyone know a player where
OGM chapters work?
3) Concatenating ogg files
This method was described here: [6]. Each chapter must be one ogg vorbis
file and then they are concatenated in one big file:
$ cat chapter1.ogg chapter2.ogg chapter3.ogg > all_chapters.ogg
PROS:
- this method is fully ogg vorbis compatible, cheap hardware players
also play these files
- foobar lists the individual files and it's able to seek
CONS:
- I found no other player so far which is able to display these "chapters"
- IMHO it's a hack and no real solution
At the moment I think that matroska is the cleanest solution, however,
maybe there are still some other possibilities?
For instance:
- Using Vorbis Comments:
Wouldn't it be easier to just use vorbis comments for chapter information ?
E.g. add to the vorbis comments:
CHAPTER01=00:00:00.000
CHAPTER01NAME=Chapter 01
CHAPTER02=00:05:00.000
CHAPTER02NAME=Chapter 02
...
If some agree on this or a some similar recommendation, is it realistic
that players will support it?
The big advantage would be, that all cheap hardware ogg vorbis players
would still be able to play at least the audio ...
- WebM Container:
Is it possible to use WebM instead of Matroska as a container?
AFAIK there is unfortunately no chapter support in WebM (although they
build on Matroska) ...
- Using OGG:
According to wikipedia, OGG is able to add chapters (see the comparison
table in [7]).
Am I missing something here? Because this would be really nice!
OK, sorry for the long mail :)
Any hints on how to create enhanced podcasts with the widest range of
support (software players, hardware players, android, ...) would be
highly appreciated.
I really like the way it is possible in MP4 and something similar as an
additional (and open source) format would be very useful!
Thanks for any hints!
LG
Georg
PS: please let me know if vorbis-dev is not the correct mailing list for
this question!
Links:
[1]: http://en.wikipedia.org/wiki/Enhanced_podcast
[2]: http://www.id3.org/id3v2-chapters-1.0
[3]: http://savvyadmin.com/adding-chapters-to-videos-using-mkv-containers/
[4]: http://en.wikipedia.org/wiki/Matroska#Software_support
[5]: http://developer.android.com/guide/appendix/media-formats.html
[6]: http://lists.xiph.org/pipermail/vorbis/2005-September/025969.html
[7]:
http://en.wikipedia.org/wiki/Comparison_of_container_formats#Information
--
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http://auphonic.com
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