We've implemented a vorbis decoder based on Tremor and as part of the documentation we're also writing about psycho acoustic models and encoding. We're quite up to date with the decoding process and psycho acoustics in general but unfortunately not on the psycho acoustic encoding used in Vorbis. We have a few questions that would we would be very thankful to have answer to: Which tricks are used? Critical bands model? Noise masking noise? Tone masking noise? Noise masking tone? Temporal masking? Other aspects of decoding: Are the codebooks fixed for VQ encoding and huffman for a given quality?. Adjustments of VQ codebooks based on the audio or picking a fixed codebook that minimizes the quantization error? Regards Johannes Sandvall, Erik Montnemery --- >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 'vorbis-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.
On Thu 5 February 2004 10:33, Johannes Sandvall wrote: <snip>> Other aspects of decoding: > > Are the codebooks fixed for VQ encoding and huffman for a given > quality?. Adjustments of VQ codebooks based on the audio or > picking a fixed codebook that minimizes the quantization error?AFAIK, the codebooks for VQ are fixed. There is a utility called rehuff, written by Segher Boessenkool IIRC, which calculates codebooks based on the specific file. Search the archives for it for more information. Lourens -- GPG public key: http://home.student.utwente.nl/l.e.veen/lourens.key --- >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 'vorbis-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.