Vorbis dev - Jan 2012 - Enhanced Podcasts with Ogg Vorbis (Chapter Marks)

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

-- 
auphonic - automatic podcast post production
http://auphonic.com
audio development, machine learning, open source and more

Overall, it's a nice summary and I don't have much to add to it.  What
it all boils down to is 'whatever you do, players don't support it...
and it will be quite a lot of work to convince them to do so."

I would think using chapters in MKA, using the Vorbis tags you suggested:
> E.g. add to the vorbis comments:
> ? CHAPTER01=00:00:00.000
> ? CHAPTER01NAME=Chapter 01
> ? CHAPTER02=00:05:00.000
> ? CHAPTER02NAME=Chapter 02
> ? ...
...or using chained Ogg files all count as clean solutions.  As you've
noticed, the only one of the above examples to have much player
support is the Vorbis option, and all of them will currently ignore
the chapter information, at least the file will play and it's not a
stretch to add the chapter capability to players that want to do so.
It's very much a 'currently most pragmatic' solution.
> 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) ...
Correct, as far as I know.
>
> - 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!
It was intended to do this via chaining, which virtually no players
chose to support :-|

Monty

Hi Monty,
>> According to wikipedia, OGG is able to add chapters (see the comparison
>> table in [7]).
> It was intended to do this via chaining, which virtually no players
> chose to support :-|
Firefox seems to be getting there, see towards the end of:

https://bugzilla.mozilla.org/show_bug.cgi?id=455165

Could jPlayer be patched to support chaining? That would seem easier
than modifying all the client-side players.

http://jplayer.org/

Cheers!

Daniel

Opinionated people are useful sometimes. ;-)
Silvia.

On Wed, Jan 18, 2012 at 6:02 PM,  <xiphmont at xiph.org>
wrote:
>> This is easy enough to map to WebVTT and thus to the way that chapters
>> work in the current HTML5 spec. We have hierarchical chapters there,
>> too, btw, so maybe that needs to be taken into account. Otherwise I
>> have no issues with this.
>
> Yay, glad to get feedback + sanity check.
>
> Monty

I agree we need to have them inline. But because of HW player
restrictions it would make sense to recommend a max image size in
bytes or a max chapter header size. If somebody has that information,
please share.

Cheers,
Silvia.

2012/4/12 Gunter K?nigsmann <gunter at
peterpall.de>:
>> But what should we do about images? Surely they should be embedded
>> into the file and not just be a url?
> If Hardware players allow for the comment size I have an argument for
> embedding images into the stream:
> Just providing links would allow to introduce 1-pixel-images with unique
> URLs into a vorbis stream to be able to track usage data for your
> podcast. Ogg streams that compromise your privacy this way sound like
> something that can generate a bad press echo one day.
>
> Kind regards,
>
> ? Gunter.
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