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This is a very cool bit of work from Frank Schoep over on [EMAIL PROTECTED] that I think might be of interest to [EMAIL PROTECTED] Very late for such a pervasive change BUT 15MB is not to be sniffed at. Frank Schoep wrote: Hi all, I've been fiddling around with the Dapper beta release and I tried an experiment with the graphics data included with it.I used a simple "find" statement and a Bash script to copy over all PNG images in the default installation and recompressed all these images using a combination of PNGRewrite, OptiPNG and AdvancePNG to see if there was any space to be saved, the results of the recompression are as follows: - original PNGs apparent bytes: 53.636.628 - recompressed apparent bytes: 38.185.898 - apparent bytes saved: 15.450.730 So, recompressing all distributed PNGs would save just over 15 megabytes in the actual default installation. The results can also be expressed in disk-blocks, since small files often take up a whole disk block the results are quite surprising: - original PNGs disk-blocks: 86.428 - recompressed disk-blocks: 72.012 - disk-blocks saved: 14.416 Looking at it this way, the recompression would save about fourteen and a half thousand disk blocks. I also looked at how well the original and recompressed PNGs would be archived using BZIP2: - original PNGs bzip2 archive in bytes: 40.028.323 - recompressed PNGs bzip2 archive: 32.109.940 - archived bytes saved: 7.918.383 So, looking at the archived versions we can save eight megabytes by recompressing the PNGs. My actual question is this: is it worth it to optimize all PNGs by recompressing them? It doesn't affect the appearance or content, it only makes each file as small as possible. By doing this, we could probably trim about seven megabytes off the install CD (which amounts to 1% of the total size) and we can cut 15 megabytes off the required hard disk space for installation. I think that because of the smaller file sizes, there's also an actual performance benefit here (or is it neglible?) To give an indication on the amount of time required for recompression: it took my Athlon 64 3200+ about 24 hours to recompress all PNGs included in the Dapper beta default desktop installation. Another proposition would be to build an automated PNG optimizer so that all PNG in packages are automatically recompressed without any user intervention. I hope my research interests some of you, if anything was unclear I'd be happy to explain more of the process and the results. Just ask away! With kind regards, Frank Schoep |
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