Hi,

I have a few questions regarding the use of the 5/3 wavelet kernel and the RCVAL parameter with the ADV212.

* The ADV212 supports the 5/3 wavelet kernel which is mathematically lossless. Does this mean that I can get an exact match of encoded image to decoded image or does this just mean that the wavelet kernel itself does not discard information when applying the transform? Is there a way to get truly lossless (encoded image matches with the decoded image 100%) with the ADV212, and if so am I restricted from setting RCVAL or do I need to use a specific RCTYPE?

* When using the 5/3 wavelet kernel I notice that you can change the RCVAL value and the compression ratio changes along with the image quality. I would think that the RCVAL register should not matter while using the 5/3 wavelet kernel b/c when someone changes the compression ratio it leads to image degradation, ie lossy image compression. Doesn't that defeat the purpose of the 5/3 wavelet kernel?

I know I am missing something here. Maybe its that I shouldn't use RCVAL at the same time as using the 5/3 wavelet kernel. Or maybe I am not understanding the purpose of the 5/3 wavelet kernel. I've been searching the internet but having little luck finding a good explanation.

Any guidance you could give would be greatly appreciated.

Thanks.

Hi Nick,

5/3 + RCTYPE = No Truncation is 100% mathematically lossless. The entropy coding process is inherently lossless-- we just truncate it to do rate control.

Wavelet kernel and rate control are two completely separate things. 5/3 isn't "lossless JPEG2000" by itself. It's an integer kernel and the 9/7 is floating point. 9/7 with no truncation will be very close to mathematically lossless but because it's not integer, it won't be 100%. That's an oversimplification but I think it's what you are looking for.

Dave