similar to: NHW Project - fast discrete wavelet transform

Hello, I have just tested new next lower quality settings (-l3 and -l4), I can diminish residual coding but if I increase wavelet coeffs threshold there is more aliasing.And even in the current mid quality settings there is some aliasing, this is the big drawback of the NHW codec. SPIHT algorithm is good for that as for example Rududu codec doesn't have aliasing at all at mid compression and

Hello, These last 2 months I have been in contact with a very impressive and friendly engineer from Intel who has written an article on my codec and the 4-5 new codecs in general that competes with HEVC.He finally answered me that as Intel is a founding member of the Alliance for Open Media and chairs several MPEG WG around HEVC, they won't be able to put extra resources on the NHW Project.So

Hello, In my last post, I seemed to say that there were no directional wavelet transforms that would give improvement to the NHW codec, but are directional wavelets an active research field today? I have also seen some recent patents on advanced and improved SPIHT, and I am a little surprised that there is no "up-to-date" state-of-the-art wavelet codec.Rududu in April 2008 was the last

Hello, These last 2 months, I have talked again with Monty Montgomery about the NHW Project and he told me that Xiph.org would like to encourage the NHW Project development.That's just great! I'll see what Monty will do on his side (and when he has time), but he also told me that the NHW codec has merits but there must be an effort to demonstrate them. The advantages, merits of the NHW

I have written a short script to estimate the size of a test of non-constant mean in an AR(1) time series. When I run the simulation on my PC (R version 2.7.1), I get the expected result: an empirical size much larger than the nominal size. On the Red Hat machine (R version 2.7.2) in my department, however, I get p-values > .45 for every simulated test. Below is my simulation code (uses

Dear all, Using R function "dwt", it seems that I cannot specify the wavelet transformation like Haar. What's the R code for wavelet decomposition which allows me to specify Haar wavelet transformation? Of course, if it can include "db2", that is even better. In general, I want an R function like matlab code "dwt". Thanks in advance! Zhen Li

Hi Raphael, On Fri, Aug 25, 2017 at 2:30 PM, Raphael Canut <nhwcodec at gmail.com> wrote: > I'll see what Monty will do on his side (and when he has time), but he also > told me that the NHW codec has merits but there must be an effort to > demonstrate them. Well, if you want to pursue a collaborative project, you need to attract others to work on it. Perhaps 'demo'

Hello all, Just a quick message for those interested in the NHW Project.I realize that I have too little time to spend on the project currently and I feel that this year will be very important after 6-7 years for its success or not.I already had some few replies from some companies (and a major one), and they can not spend some time, spend some engineers on my work because there is no

Hello, Definitely not any (constructive) comments on the NHW Image codec? According to my tests, it can compare good with reference codecs like x264 intra and WebP. Yes, the codec is still experimental and is optimized for visual (subjective) evaluation, not PSNR.Its main feature is again that it would have a little more neatness/sharpness and a little less precision (residual coding is applied

Hello, I would like to discuss a little about the NHW codec and its state after nearly 5 years on the Xiph forums. I also know that if I would like to discuss I'd better go to the great Doom9 and Encode.ru forums but for now I find that my codec is too experimental for these professional forums: - the codec is only for fixed 512x512 size, just a test tool. - there is only mid compression -

Hello, No advance for now on the NHW codec, I am still working on a new quantization scheme to scale down the compression ratios but without luck... Any advice, idea is very welcome.I will also have to correctly code the wavelet filerbank and process on rows and columns and suppress the image transposition (this is for long overdue)... will win few cycles... there are other parts to speed up (in

Hello, I know there is no community around NHW, but I would have liked to know what you would like to see improved in the NHW codec.I know its results are not perfect for now compared to high-end AV1/VVC codecs for example, but could be ok giving its extremely fast speed.-However on high quality images, I notably like its good results because of its neatness.- Regarding things to improve, there

Raphael, I do not believe it is possible to build a viable community around most hardware projects except super-universal based on very cheap/high-volume products like Pi or Arduino. We see the commercial benefits of Free Software/Open Hardware as it adds value to the hardware as users are ready to pay extra for the Freedom. Andrey ---- On Thu, 02 Dec 2021 12:59:34 -0700 Raphael Canut

Hello, I don't have advanced on the NHW codec, but now, as a lot of people, 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

Hello, I've found some time to get back to the NHW Project.In fact a Xiph forum member told me that even if I will start a new job, he hopes that I will still continue to develop a little the NHW Project, on my spare time.I told him that I would furthermore spend my spare time on the NHW Project if a community around the project could emerge... and he told me that certainly the best way for

Hi Andrey, Thank you for your answer.Actually, NHW is very low-power so I think it could be geared toward any hardware.But actually I don't have hardware skills, so NHW is not a real hardware project for now maybe? I agree with you that it is extremely difficult (for me) to build a community around NHW, I'm certainly very bad/underskilled at it.Any help is welcome! Cheers, Raphael Le

I take the liberty of pasting the on-line documentation for package "wavelets", functions "dwt" and "wt.filter", pertinent to the wavelet/filter choice. While I apologize for my verbose messages with huge attachments, I encourage whoever loads packages to CRAN to take some minutes to reread the attached documentation. Usage dwt(X, filter="la8", n.levels,

Hello, I have improved a little the NHW codec.I have improved the dequantization in the wavelet HH band, and little improved the -l2 (and lower) quality setting.I have also added a -l3 lower quality setting (-15Ko, exp), I have increased the quantization for this other setting, and I start to remove higher wavelet coefficients, but this is not optimal... The artifacts start to be noticeable for

Hello, I am still progressing with very high compression and I have corrected a processing, so now very high compression (-l10 to -l13 quality settings) has really better precision and so better quality. I have also released a first draft of a new -l14 very high compression quality setting. More at: http://nhwcodec.blogspot.com/ Just a remark, the entropy coding schemes start to be less

Hello all, It's me again.Just a quick message to tell that I finally do not agree that HEVC (don't have tested AOM AV1 for now) is better than the NHW codec at mid compression. Last night, I dowloaded 30 images of Star Wars Rogue One on the web and I made another comparison with x265 (HEVC) for mid compression (-l2 to h2 settings for the NHW codec). Visually, I prefer the results of NHW