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it only works because you chose a particularly bad test case, that has a lot of 1s and 0s that repeat nicely, and also because you made the picture a specific format - nicely aligned at 8 pixels or 8 multiples. Actually, it's 173 bytes and 109 bytes but final size includes the headers (which include the input file name, so had i used a.b as file name the final file size would have been a few bytes smaller)Īnd this PAQ is just one of the latest, I didn't pick one that's specially optimized for text input, not sure this one is.Īgain. and even managed to shrink the 256 bytes with characters that don't repeat down to 207 bytes. So it managed to compress those 2048 1s and 0s into 138 bytes, better than PNG.
GIFT OF SPEED PNG COMPRESSOR ARCHIVE
Time 0.11 sec, used 1017681280 bytes of memoryĬ:\Temp\topng>paq8jc.exe -7 input.paq input.txtĬreating archive 8jc with 1 file(s).
GIFT OF SPEED PNG COMPRESSOR DOWNLOAD
but there are compressors which works with bits and have extremely complex compression schemes, like let's say the PAQ compressors.ĭownload one of the latest versions and play with it - the PAQ page is here : and here's direct download link to PAQ8 : Ĭ:\Temp\topng>paq8jc.exe -7 input_ascii.paq input_ascii.txtĬreating archive input_8jc with 1 file(s).
GIFT OF SPEED PNG COMPRESSOR CODE
The original ASCII code table of 256 bytes won't compress well, because compressors typically look for bytes and sequences of bytes that repeat. So using Bzip bytes down to 419 bytes (20.45%) and PPMd got it down to 478 bytes (23.33%) ħzip compressed it down to 419 or 478 bytes, depending on the algorithm used - 7zip supports BZip2 which is optimized for text, and PPMd which can work great for some inputs but is single threaded and slow, and LZMA and LZMA2 which are the defaults, but which are optimized for multi-threading and BIG files so they have a lot of overhead, small files don't compress as well. So you get 256 x 8 bytes = 2048 bytes - and by the way your input file only had 254 ascii codes.
GIFT OF SPEED PNG COMPRESSOR FULL
In real world, an input text will not be so "consecutive" it will be more random, a book or some executable file will be full of random bits, they're not all gonna align to have big squares or rectangles of 0s and 1s that compress well, your picture will be like snow on old analogue TVs, the png filters won't find a lot of "tiles" that repeat themselves enough times to be worth adding that tile to an internal dictionary.Īnyway, for kicks, I reproduced your example by making my own ASCII codes file (without newlines) and compressing it. If you made it 10 bit wide, or some other weird shape that's not multiple of 8, the pattern may be distorted enough to not compress as well. this particular input example works so well because between each line, more or less only 1 bit or more changes, a lot of the bits are the same, so PNG finds a lots of "tiles" that repeat so they compress well. The compressor finds a tile that 2x2 pixels, or 2x4 tile or even 4x4 that will then appear again in the image, so it can put such tile in a "dictionary" and when it detects this tile again, it just uses a couple of bits to point to it in dictionary. You gave the compressor the ASCII table, which has big chunks of 0s and 1s, for example your first four lines would be: PNG has some "filters" and also looks for "tiles" of pixels that repeat in an image, in order to compress well areas of an image that have the same color : think of a screenshot of this forum, or think of an excel chart, or whatever.
Had you made the image something that's not a multiple of 8, it would have failed. Regular file compressors are not optimized for specific niche cases, they're designed for lots of inputs.įurther, you also "helped" the png compressor by giving it the ideal format to work with, you made the image nicely aligned at 8 pixels wide. You took an extremely nice example of an input, which happens to compress very well as an image.
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