[Vorbis-dev] Ogg vorbis decoder - Independent implementation
jripley at rioaudio.com
Mon May 23 07:46:28 PDT 2005
Vinoth Kumar wrote:
> Hi All,
> Ours is an embedded software solutions company that focuses on
> developing embedded software solutions specific to the DSP market. I'm
> happy to inform the ogg vorbis developer community that today we have
> release trial version of our Ogg vorbis decoder made available on PC,
> TMS320C67x platform (More platforms to follow). More information about
> the same can be fetched from
> www.vinjey.com/ogg.html <http://www.vinjey.com/ogg.html>
> Now there is couple of questions for which we are looking for the answers.
> a. What are the set of conditions we need to oblige before using the
> Xiphophorus and Ogg Vorbis logo on our website?
> b. Ours is an independent implementation of the Ogg vorbis decoder. We
> are interested in knowing about whether there are any other independent
> implementations of ogg vorbis decoder available?
I've written one, although the only version I have up on a web page is
rather old (Jan 2004!) and not the nice tidy version it's become since
then (honest!) It's at http://www.pslam.demon.co.uk/specbis-0.05.tar.gz
I wrote it to test out the viability of strictly controlled memory
management, and to test out some ideas for encode/decode more easily
than the reference codebase could. It's also a bitrate peeler.
What method have you used to implement bitrate peeling? The method I
used was to patch the encoder to force "low" and "high" quality residue
into passes 0-2 and 3-7 respectively. This generates a file slightly
larger than just encoding at "high" without peeling support. The peeler
can then go through the bitstream and throw away passes 3-7. This
results in a file roughly the same size as it would be when encoded at
"low". It's extremely fast and works surprisingly well, but it's a very
brutal and unpolished method and the sound quality is barely passable.
I take it there's no freely available source code?
- John Ripley.
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