Displaying 20 results from an estimated 2000 matches similar to: "NHW Image codec"
2016 Mar 24
1
NHW codec - progress 2
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
2016 Aug 16
0
NHW codec
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
2017 Sep 04
0
NHW Project - fast discrete wavelet transform
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];
2016 Mar 16
0
NHW codec - progress
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
2017 Aug 30
0
NHW Project - news with Xiph.org
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'
2017 May 27
0
NHW Codec - aliasing
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
2017 Aug 25
4
NHW Project - news with Xiph.org
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
2018 Mar 10
0
NHW Project - lower quality settings
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
2013 Jun 19
0
NHW Image codec - lower quality settings
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
2013 May 29
1
NHW Image codec - 2 lower quality settings
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
2017 Feb 02
0
NHW codec - precision
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
2018 Mar 09
0
NHW Project - lower quality settings
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
2018 Mar 10
2
NHW Project - lower quality settings
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
2017 Nov 30
0
Fwd: NHW Project - speed comparison with x265
---------- 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
2017 Feb 20
0
NHW Project - some advice
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
2018 Dec 12
0
NHW Project - good quality improvement & new -l14 very high compression quality setting
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
2016 Oct 01
0
NHW codec
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
-
2015 Aug 18
1
Standardization FLAC through IETF
Dear members of the flac-dev list,
I'm writing to ask for feedback from the FLAC community regarding the
possibility of standardizing the FLAC specification through the Internet
Engineering Task Force. I'm working with MediaArea on the PREFORMA project
which focuses on building conformance checkers for Matroska and FFV1. Since
Matroska and FFV1 are not yet formally standardized, this
2012 Jul 25
4
NHW Image codec - improvement of precision
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,
2015 Jan 23
0
NHW Image codec
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