ROI-based encoding， the block artifacts and ROI region offset issue.

[mlkk518]

Thank you very much for your open source work. I am using your code to test ROI-based encoding, and the block effect is especially obvious at low compression rates, and the region corresponding to the ROI mask is also offset from the actual region. The input image I am using is 640x640x3, and the ROI mask is also of equal size. In the ROI.txt file, I set the parameters as follows.

roi.txt： 640 640 20 20 ... 20 (repeat 640) 20 20 ... 20 .... (640x640 array) where the value of the ROI region is 10, and the NROI is 20. Could you please tell me what is the reason, and how can I solve it? Thank you very much!

The following is the experimental results:

(1) Original image:

(2) ROI mask:

(3) Decoded image: (bpp=0.0392)

Looking forward to your early reply！