search for: pvq

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Dear Celts, I've become intrigued by the problem of spherical quantizers, so I decided to see if I could come up with something better than PVQ. What I wound up writing is something I call an "octagon quantizer. In two dimensions, PVQ uses a "diamond" (square) shape. An octagon code (OVQ) uses an octagon, which is a much better approximation to the circle. In two dimensions, PVQ uses an octahedron, and OVQ uses a rhombic...

The attached code implements PVQ encoding/decoding with separated signs [1]. It's in Python to use the unlimited-precision integers. The concept is to map vectors on some L-dimensional pyramid into integers 0...N, just like the standard PVQ. The only change is the mapping itself. The mapping is altered so that all sign dat...

Hi, I'm studying at ETH Zurich and want to use a pyramid vector quantization for my semester thesis. Unfortunately, I have some troubles with generating the codebooks for high dimensions. For vectors with dimension bigger than 12 it takes such a long computation time to generate. I thought maybe you could help me out with a efficient way to do this? Is there some code available? Thanks for

...ple, I am following the AOMedia AV1 codec.Just a (late) update of my previous post, there won't be problem in AOM AV1 with the CABAC scheme, as the codec will use Daala's multi-symbol entropy coder and/or ANS.That's great! I have even read on the wiki page, that AV1 will use Daala's PVQ as quantization scheme.Wow. Also as a consequence, there are fewer interest now in the NHW codec, but I would still like to maintain it as an open-source and royalty-free project, for those interested in wavelet technology. I would like now to completely change the quantization scheme and also may...

Hi, In paper" A High-Quality Speech and Audio Codec With Less Than 10 ms Delay", you are mention that: There are still several ways to improve CELT, such as by incorporating better psychoacoustic masking in the dynamic bit allocation. This is a difficult problem both because there are few bits available for coding the allocation and because the analysis window is short. it is

Hi All, It is possible to make Opus/CELT a lossless coder if I allow a sufficiently high bit rate? We considered using FLAC, but FLAC's latency is well beyond the acceptable range. Thanks -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.xiph.org/pipermail/opus/attachments/20120822/60c69469/attachment.htm

.... This calculation relies on computing dot(m,s). Since m and s are coded with error, the calculation of theta will also have error. Some quantization error in theta doesn't seem intrinsically unreasonable, but if m and s have enough error, the above procedure can derive a contradiction. For PVQ with a small number of pulses, it seems likely that dot(m,s) could be zero, even though |L| != |R|. The decoder then finds itself in a very awkward situation. I believe this can be remedied with a bit of edge-case handling, though. - --Ben -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU...