Posted by member 42328 on 2003-06-27 15:15:21 link
I look forward to hearing from you ilmcuts.
JPEG also has big compression ratios when the colors within the pixel block are the same. After setting all the seperate pixel windows to single colors, it performs another algorithm (gee, its only been 4 months and I've forgotten all these terms) to compress all the like pixel windows. Very lossy once completed and completely irreversible. I believe groups of 8x8 pixels should be uniformly colored so in the end there should be less color difference than the original BMP file. This would be why highly compressed MPEG videos are blocky; it uses the same technology.
I never really went into the PNG compression algorithms but it doesn't make sense to me why the compression would be drastically different when going from a high-detail lossless BMP image and a lossy low-detail JPEG image.
-Jon
JPEG also has big compression ratios when the colors within the pixel block are the same. After setting all the seperate pixel windows to single colors, it performs another algorithm (gee, its only been 4 months and I've forgotten all these terms) to compress all the like pixel windows. Very lossy once completed and completely irreversible. I believe groups of 8x8 pixels should be uniformly colored so in the end there should be less color difference than the original BMP file. This would be why highly compressed MPEG videos are blocky; it uses the same technology.
I never really went into the PNG compression algorithms but it doesn't make sense to me why the compression would be drastically different when going from a high-detail lossless BMP image and a lossy low-detail JPEG image.
-Jon