theora dev - Feb 2004 - lib-multiogg

As ogg gains more codecs, moving forward into the brave new world of
multi-codec streams, the cutting edge cannot press forward effectively
without a way to abstract out many of the parts of dealing with
multi-codec ogg streams.   It's tricky to get these things right.  Every
program that uses ogg needs a reliable way to find out when chained
streams begin and end, which codecs a given stream contains, and so on.

So I only would have to get that trickiness done right once, and to
greatly reduce the amount of duplicated work between programs that deal
with multi-codec streams like audio streaming servers and source
clients, I've been working on a little library.  I think I might call it
lib-multiogg.

Right now, it helps my personal versions of libshout and icecast
understand and stream flac, and, beautifully but without a great player,
theora+vorbis talkies.  It doesn't do seeking or decoding yet, just the
metadata and elapsed playback time that icecast and libshout would need,
but perhaps it could be extended to do decoding or even encoding.  

It might turn out kindof like VorbisFile only not just for vorbis.

If there's interest I can clean up my code so more people can play with
this.

The future of open source streaming media is waiting.

- Daniel Holth

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On Sun, Feb 22, 2004 at 12:36:08AM -0500, Daniel Holth
wrote:
> As ogg gains more codecs, moving forward into the brave new world of
> multi-codec streams, the cutting edge cannot press forward effectively
> without a way to abstract out many of the parts of dealing with
> multi-codec ogg streams.   It's tricky to get these things right. 
Every
> program that uses ogg needs a reliable way to find out when chained
> streams begin and end, which codecs a given stream contains, and so on.
Monty has been talking about writting OggFile as part of libogg2, but 
progress on this has been... slow.  I agree that any multi-codec library 
at this point would be a huge benefit to us all, and IMHO the lack 
thereof is a large chill-factor towards non-Vorbis adoption.

It'd be great to see atleast something in place right now for 
multicodec support, even if it requires modification to add additional 
codecs (no plugins, but keeps the same client API).  If OggFile ever 
comes into existance it'll surely be better and worth switching to, but 
I don't think we should let the plans to write it prevent an 
less-complex alternative which can be written sooner rather than later.

Do you have an API for this yet?  You were talking about this yesterday 
but if you have code already it'd be great if you could share and get 
some feedback on it.  

--- >8 ----
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Hi all,

I've been working on a library called liboggz for a while now.

Features:

  * handles multiple codec streams
  * for reading, it can seek across multitrack/multi-codec streams,
  * for writing, it interleaves with packet queuing
  * for seeking convenience, transparently parses theora, speex, vorbis
    headers without requiring linking to those libs (ie. for server use)
  * simple callback based open/read/close or open/write/close API
  * strict adherence to bitstream spec -- writes can fail if you try to
    write illegally structured packets
  * fairly complete API documentation
  * fairly complete test suite
  * BSD style license

it's pretty reliable by now; we've been using it in a few projects for
annodex.net, though it's a generic ogg library with no codec dependencies.

it's available at:

  http://www.annodex.net/software/liboggz/

I'd suggest getting the cvs version, 0.8.0 was released about a month
and some little bugs were fixed since (of course :). The docs are also
available online:

  http://www.annodex.net/software/liboggz/html/

oh and it comes with oggzdump and oggzdiff tools for hexdumping and
comparing hexdumps, which are useful if you're hacking bitstreams :)

enjoy :)

Conrad.

On Sun, Feb 22, 2004 at 01:07:16AM -0500, Arc Riley
wrote:
> On Sun, Feb 22, 2004 at 12:36:08AM -0500, Daniel Holth wrote:
> > As ogg gains more codecs, moving forward into the brave new world of
> > multi-codec streams, the cutting edge cannot press forward effectively
> > without a way to abstract out many of the parts of dealing with
> > multi-codec ogg streams.   It's tricky to get these things right. 
Every
> > program that uses ogg needs a reliable way to find out when chained
> > streams begin and end, which codecs a given stream contains, and so
on.
> 
> Monty has been talking about writting OggFile as part of libogg2, but 
> progress on this has been... slow.  I agree that any multi-codec library 
> at this point would be a huge benefit to us all, and IMHO the lack 
> thereof is a large chill-factor towards non-Vorbis adoption.
> 
> It'd be great to see atleast something in place right now for 
> multicodec support, even if it requires modification to add additional 
> codecs (no plugins, but keeps the same client API).  If OggFile ever 
> comes into existance it'll surely be better and worth switching to, but
> I don't think we should let the plans to write it prevent an 
> less-complex alternative which can be written sooner rather than later.
> 
> Do you have an API for this yet?  You were talking about this yesterday 
> but if you have code already it'd be great if you could share and get 
> some feedback on it.  
> 
> --- >8 ----
> List archives:  http://www.xiph.org/archives/
> Ogg project homepage: http://www.xiph.org/ogg/
> To unsubscribe from this list, send a message to
'theora-dev-request@xiph.org'
> containing only the word 'unsubscribe' in the body.  No subject is
needed.
> Unsubscribe messages sent to the list will be ignored/filtered.
--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
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