similar to: NHW Image codec

Hello, Just a quick message to correct what I have said in my previous post.It finally seems not that easy to code small wavelet coefficients to have a good precision, and SPIHT is certainly a very good algorithm for that, -and I know there are SPIHT experts that can make very good SPIHT-based codecs-.I have chosen a new and different approach, the multistage residual coding, so I will try to

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 forgot in my last reply that my DWT implementation can be speed up, for example I'm doing for now: for (;_X1<_E_;_X1++,_RES+=2) //dilatation { _RES[0]=_X1[0]<<3; _RES[1]=(_X1[1]+_X1[0])<<2; } then for (;_X2<_E_;_X2++,_RES+=2) //details { _RES[0]-=(_X2[1]+_X2[0])<<1; _RES[1]+=6*_X2[1]-_X2[2]-_X2[0];

Hello, I am slowly working on the NHW codec, I think now that I will remove the (multistage) residual coding, because it consumes too much bits while leaving still some artifacts.Instead, it seems better to simply have a finer quantization (and use a quantization step of 4 instead of 8).For the higher compression settings, I will need a good "psycho-visual" quantization to know which

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, 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

I don't mind at all. I imagine there are more people like me out there who have been following your work, but haven't said anything. I agree that a series of pages explaining how things work may lead to more contributions. At the very least it would lead to more people being better educated on how wavelets work in image compression. But, this is your project, if you don't have the

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

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 have finally added 2 lower quality settings for the NHW codec: -l1 (-5Ko) and -l2 (-10Ko).I use a quantization of 0.935 and 0.88 (kind of quantization), and I decrease residual coding on the first order wavelet image. I have updated the demo page: http://nhwcodec.blogspot.com/ . These 2 lower quality settings are still experimental.If you could find time, would be interested in any

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 have re-tested -l4 high compression setting and it's clear that it lacks of precision on degraded, rather blurred images. So I don't know if it is a good idea to base the other lower quality settings (-l5,-l6,...) on -l4 setting.I have tested the NHW codec against x265, x264, Daala, WebP, Rududu, DLI and it's clear that at high compression these very good codecs have more

Hi David! Many thanks for your very encouraging and kind feedback!!! (Hope you don't mind that I made your post public on the Theora channel). I try to be the more sincere as I can in my posts.Some people suggested me to make demo pages to explain how the codec works step by step, and I realize that it would be good, because certainly it will show that the NHW codec is not that complex and

---------- Forwarded message ---------- From: Raphael Canut <nhwcodec at gmail.com> Date: 2017-11-30 14:22 GMT+01:00 Subject: Re: [theora] NHW Project - speed comparison with x265 To: fboehm <fboehm at aon.at> Hi Franz, Many thanks for your answer!!! > I appreciate your enthusiastic work on such a complex project like writing a video codec Yes, for now the NHW codec is more an

Hello, Ok that's right HEVC and AOM AV1 are better than the NHW codec, even at mid compression.I only tested my codec with quite neat images, hence the good results, but on more blurred, more compressed images, HEVC and AOM AV1 are definitely better, they are also exceptionnal at high compression. So, yes that's right, the NHW codec has very little chance to penetrate the market, it is

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, 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 -

Hi again, I have improved precision of my codec (on the encoder and decoder).I have also improved the -h1 quality setting.-Source code and binaries at http://nhwcodec.blogspot.com/-. I am still trying to improve precision of my codec, with keeping my low-complexity (fast) approach. I do not totally use the reference (and impressive) block prediction with different modes + residual coding scheme,

Hello, So here is the compression scheme that I don't know if is covered by patent. I use it on the wavelet DC parts.It outputs 1 byte (8 bits) words.There is 5 modes: - 1(MSB) | 7 bits to store value (0->127 range) - 01 | 6 bits to store val[n+1]-val[n] | val[n]-val[n-1] if each in the range [-4,4] - 001 | 5 bits to store val[n+2]-val[n+1] | val[n+1]-val[n] | val[n]-val[n-1] if each in

Hello, Happy New Year to the forum!!! I am still working on removing the aliasing from the decoded Y frames, but it is not that easy, I am also looking for a rather cheap solution... I will insist on it, because once it's done it will open the door to high compression and increasing wavelet coeffs threshold of the dead-zone... The NHW Project has new approaches: it has a good neatness and