RDO GPU texture encoders increase the number/density of LZ matches in the encoded output texture. He's a file entropy visualization of kodim18.dds. The left image was non-RDO encoded, the right image was encoded with lambda=4.0 max backwards scan=2048 bytes.
Non-RDO:
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Non-RDO, one byte matches removed:
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Non-RDO:
RDO:
Non-RDO, one byte matches removed:
RDO, one byte matches removed:
fv docs:
"The output is fv.bmp with the given size in pixels, which visuallyTool source:
displays where matching substrings of various lengths and offsets are
found. A pixel at x, y is (black, red, green, blue) if the last matching
substring of length (1, 2, 4, 8) at x occurred y bytes ago. x and y
are scaled so that the image dimensions match the file length.
The y axis is scaled log base 10."