[vorbis-dev] Silent Vorbis Packet

[Daniel Kenyon Jones]

Hi Tor-Einar,

First of all, thx for the library, it saved me a lot of time/effort.

"Receiver Driven Layered Multicast" isn't my idea. It was developed at
Berkeley [ http://citeseer.ist.psu.edu/steven96receiverdriven.html ].

For my dissertation I've developed an implementation of RLM using Vorbis
as the codec. Although I've used the JMF, due to time pressure and the
bizarre JMF documentation, the implementation only uses bits of the JMF
to handle Vorbis packet extraction and final payout rather than using
the streaming libraries.

|Ogg | _\ | Logical  | _\ |Custom layering| _(multicast)_\ |custom| ____
|File|  / |Ogg Stream|  / |& Streaming app|              / |client|  

___\ |JMF Vorbis|
   / |  Decoder |

I didn't have huge hopes for the audio quality of the project given the
general pessimism on the list on using bitrate peeling with the current
Vorbis encoder. This wasn't of huge concern as I've been focusing mainly
on the networking aspect of the project.

...but, I managed to get quiet reasonable sound quality for very crude
method of splitting. It is not as good a re-encoding at the target
bitrate, but the results are still very good (eg. no buffering when
switching quality, can be used over multicast). I'll stick a copy of the
server/client online once they are finished/I have time.

My project supervisor at the Labs has picked up some of my work, and is
researching using layered Vorbis for audio streaming. (He is working
with the original C Vorbis libraries rather than J-Ogg)

The final code has to be finished by May, but it should get done in the
next one or two weeks. 


-- 
Daniel Kenyon Jones

Emmanuel College, Cambridge
dk282 at cam.ac.uk

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