According to the specifications, the Controller has a 256K color display (should that really be 256,000 or 256?), yet the quality of displayed colors is nowhere near what it could be on a 256 color screen. The display quality looks like the image is quantized to a fixed set of colors without follow-up by error dithering to correct quantization errors.
A 256 color display can display images much better than what the Controller currently does. The trick is to apply dithering to compensate for the quantization error. (For instance Floyd-Steinberg dithering is excellent - sample code can be found in the libjpeg package). If the Controller uses a LCD with 256K colors, then the problem is possibly the lack of error dithering to compensate for bit truncation done by the LCD. I have scanned all my album coverart in 700x700 pixels (150dpi) and store them in JPEG format. The defects show up more obvious on some artwork than other. I have attached images of the artwork of one of my CDs where the defects are obvious. artwork.jpg : Source image provided to SqueezeCenter controller.jpg : Source image converted to a palette of 256 fixed colors without using error dithering. The Controller displays the artwork pretty much this way. The defects are in the same locations and of the same type. errorcorr.jpg : Source image converted to a palette fixed colors using Floyd-Steinberg error dithering. Looks much better, doesn't it? Thoughts? Is the problem what I suggest it is? Any chance this will be improved? Thanks, Peter The two similated images were created with PMView Pro avalaible at www.pmview.com. Note that the Forum software converted my two original 256-color GIF images to JPEG. +-------------------------------------------------------------------+ |Filename: errorcorr.jpg | |Download: http://forums.slimdevices.com/attachment.php?attachmentid=4533| +-------------------------------------------------------------------+ -- pnielsen ------------------------------------------------------------------------ pnielsen's Profile: http://forums.slimdevices.com/member.php?userid=11801 View this thread: http://forums.slimdevices.com/showthread.php?t=44442 _______________________________________________ discuss mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/discuss
