ogg dev - Aug 2014 - Merging Ogg streams whilst updating the Skeleton?

Hi All

I'm currently trying to put together an ogg file with two theora streams, 
a handful of audio streams (probably mixed vorbis and opus), and a 
Skeleton stream that describes their relationships to each other. I had 
hoped to be able to use the oggz suite of tools, but I can't seem to get 
that to work.

To generate my theora files, I'm using ffmpeg2theora, which will happily 
generate me an ogg file with a single theora stream, and with or without a 
skeleton stream for it. If I generate two of them, without skeleton 
streams, and then use oggz-merge to splice them together, no skeleton 
stream is added. If I use oggz-merge on two both with theora+skeleton, 
then I end up with a file with two skeleton streams, both claiming to hold 
role=video/main, which doesn't seem correct to me. I can use oggz-merge to 
merge in the audio tracks too, but they don't show up in either skeleton, 
which seems wrong too.

Can anyone suggest the best way to go about merging together these various 
streams, so I end up with a Skeleton stream properly describing how they 
fit together?

And related - is the behaviour of oggz-merge when merging two 
skeleton-containing files to end up with a file with two skeleton streams 
correct, or should I report a bug for that?

Thanks
Nick

PS I'm creating these multi-stream files to test the handling of
    multi-stream files in the Ogg and Vorbis Java library I maintain, to
    help check if the proposed Apache Tika multi-stream metadata proposal
    will work, so I'm a long way down the rabbit hole here!

What does oggz-info tell you about the file when you've merged it
(without skeleton)? It may say that there are two logical video
bitstreams, because they've come from different files. So, two
skeletons may actually be correct.

I hear that ffmpeg has a a concat feature. Not sure how it does it.

There's also OggCat
(http://en.flossmanuals.net/ogg-theora/command-line-editing/cat-files/).
However, you have to make sure that the video is encoded with the same
parameters (same resolution, audio encoding parameters).

Multiple skeletons are actually valid, so you should be able to deal with it!

HTH.

Cheers,
Silvia.


On Sat, Aug 23, 2014 at 3:54 AM, Nick Burch <ogg at gagravarr.org>
wrote:
> Hi All
>
> I'm currently trying to put together an ogg file with two theora
streams,
> a handful of audio streams (probably mixed vorbis and opus), and a
> Skeleton stream that describes their relationships to each other. I had
> hoped to be able to use the oggz suite of tools, but I can't seem to
get
> that to work.
>
> To generate my theora files, I'm using ffmpeg2theora, which will
happily
> generate me an ogg file with a single theora stream, and with or without a
> skeleton stream for it. If I generate two of them, without skeleton
> streams, and then use oggz-merge to splice them together, no skeleton
> stream is added. If I use oggz-merge on two both with theora+skeleton,
> then I end up with a file with two skeleton streams, both claiming to hold
> role=video/main, which doesn't seem correct to me. I can use oggz-merge
to
> merge in the audio tracks too, but they don't show up in either
skeleton,
> which seems wrong too.
>
> Can anyone suggest the best way to go about merging together these various
> streams, so I end up with a Skeleton stream properly describing how they
> fit together?
>
> And related - is the behaviour of oggz-merge when merging two
> skeleton-containing files to end up with a file with two skeleton streams
> correct, or should I report a bug for that?
>
> Thanks
> Nick
>
> PS I'm creating these multi-stream files to test the handling of
>     multi-stream files in the Ogg and Vorbis Java library I maintain, to
>     help check if the proposed Apache Tika multi-stream metadata proposal
>     will work, so I'm a long way down the rabbit hole here!
> _______________________________________________
> ogg-dev mailing list
> ogg-dev at xiph.org
> http://lists.xiph.org/mailman/listinfo/ogg-dev

On Sat, 23 Aug 2014, Silvia Pfeiffer wrote:
> What does oggz-info tell you about the file when you've merged it
> (without skeleton)? It may say that there are two logical video
> bitstreams, because they've come from different files. So, two
> skeletons may actually be correct.
There should be (and are) two logical video streams - I'm trying to create 
a file with a "main" video, "alternate" video and a few
different
soundtracks.
> I hear that ffmpeg has a a concat feature. Not sure how it does it.
I'm trying to merge though, not concatinate!
> Multiple skeletons are actually valid, so you should be able to deal 
> with it!
If there is one file containing video #1 followed by video #2, I could see 
it wanting multiple skeletons. I may have mis-read the specs, but for one 
video with main video + alternate angle video + english audio + french 
audio, I would've thought that should be one skeleton with a fisbone per 
track, with the fisbone's describing the relations between the tracks?

Thanks
Nick