<div>Hello,</div><div> </div><div>I have just re-tested my codec with the YCbCr color space, used in JPEG for example, and that's right that YCbCr is better, more accurate (than YUV).Files are 10% larger, but the results are better with more precision.Maybe I should use this color space by default? I have just added a YCbCr version on my demo page (this version can be compiled from the source code by selecting the YCbCr color space, and with removing the x298 multiply for Y in the decoder...).Any comment is welcome.<br>
</div><div>For the frequency prediction and the small wavelet coefficients, it is certainly a wrong approach to try to predict specifically small frequency coeffs (wavelets, DCT,...) one by one, and that's certainly why I couldn't have any result..., and a better (common) approach is certainly to predict a block of coeffs (freq) or pixels, and then study the variance of the residuals (prediction errors), -and if the variance of the residuals is smaller than the variance of the original block, then prediction is good-.I will have to study it, but it is rather complex... </div>
<div> </div><div>Anyway, any comment on this new version is very welcome.</div><div> </div><div>Many thanks again,</div><div>Raphael</div><div><br> </div><div class="gmail_quote">2012/7/25 Raphael Canut <span dir="ltr"><<a href="mailto:nhwcodec@gmail.com" target="_blank">nhwcodec@gmail.com</a>></span><br>
<blockquote style="margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-left-style:solid" class="gmail_quote"><div>Hi again,</div><div> </div><div>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 <a href="http://nhwcodec.blogspot.com/" target="_blank">http://nhwcodec.blogspot.com/</a> -.</div>
<div> </div><div>I am still trying to improve precision of my codec, with keeping my low-complexity (fast) approach.</div><div>I do not totally use the reference (and impressive) block prediction with different modes + residual coding scheme, but I just apply residual coding on the first order wavelet "image" (for example for a 512x512 image, I just code the errors on the 256x256 wavelet "high-resolution" part), hence the lack of precision.I try to compensate it with a little more neatness of the wavelet 5/3 filterbank, but that's right that precision seems visually more important.</div>
<div> </div><div>Any opinion on this approach or on the codec in general is very welcome.</div><div> </div><div>Many thanks again,</div><div>Raphael</div>
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