compression

I am looking for a compression library to use in iPhone application supports decompressing AES 256-bit archives built in Winzip compression utility. Thanks. zlib is part of the iPhone sdk and is a well established and free option. If you're using Xcode you can add it to your project by: Right clicking on the Frameworks folder in your project (you can do it elsewhere but that's likely where you want to put it) Select add file Select existing frameworks Select libz.1.2.3.dylib Thank you very much for the help I finally ened up using ZipArchive library from: http://www.artpol-software.com I had

I need to compress multiple files into a single archive using Delphi. I'd prefer to use freeware components or open-source components because I am very very cheap :-) My primary requirements are: Possible to encrypt the archive Can create common archives that can be opened by anyone with a copy of WinZip Does anyone have suggestions with components that they have used? Please feel free to suggest free as well as commercial components/libraries. schnaader Perhaps DelphiZip is what you are looking for, it seems to support encryption, too, and is WinZip compatible. It is released under LGPL.

Can anyone explain in a simple clear way how MPEG4 works to compress data. I'm mostly interested in video. I know there are different standards or parts to it. I'm just looking for the predominant overall compression method, if there is one with MPEG4. MPEG-4 is a huge standard, and employs many techniques to achieve the high compression rates that it is capable of. In general, video compression is concerned with throwing away as much information as possible whilst having a minimal effect on the viewing experience for an end user. For example, using subsampled YUV instead of RGB cuts the video

JPEG is a lossy compression scheme, so decompression-manipulation-recompression normally reduces the image quality further for each step. Is it possible to rotate a JPEG image without incurring further loss? From what little I know of the JPEG algorithm, it naively seems possible to avoid further loss with a bit of effort. Which common image manipulation programs (e.g. GIMP, Paint Shop Pro, Windows Photo Gallery) and graphic libraries cause quality loss when performing a rotation and which don't? Boojum Yes, it is possible for certain cases: 90-degree rotations and flips on images. The heart

Can someone please explain to me how the zlib library works in Nodejs? I'm fairly new to Nodejs, and I'm not yet sure how to use buffers and streams. My simple scenario is a string variable, and I want to either zip or unzip (deflate or inflate, gzip or gunzip, etc') the string to another string. I.e. (how I would expect it to work) var zlib = require('zlib'); var str = "this is a test string to be zipped"; var zip = zlib.Deflate(str); // zip = [object Object] var packed = zip.toString([encoding?]); // packed = "packedstringdata" var unzipped = zlib.Inflate(packed); // unzipped = [object

I ran a Google Page Speed and it says I scored 57/100 because I need to "Enable Keep-Alive" and "Enable Compression". I did some Google searches but I can't find anything. I even contacted my domain provider and asked them to turn it on, but they said it was already on. Long story short: 1.) What is Keep-Alive? 2.) How do I enable it? Keep-alive is using the same tcp connection for HTTP conversation instead of opening new one with each new request. You basically need to set HTTP header in your HTTP response Connection: Keep-Alive Read more here Configure Apache KeepAlive settings Open up