compression

问题 I have hundreds of thousands of sparse bit strings of length 32 bits. I'd like to do a nearest neighbour search on them and look-up performance is critical. I've been reading up on various algorithms but they seem to target text strings rather than binary strings. I think either locally sensitive hashing or spectral hashing seem good candidates or I could look into compression. Will any of these work well for my bit string problem ? Any direction or guidance would be greatly appreciated. 回答1:

问题 I have many large gzip files (approximately 10MB - 200MB) that I downloaded from ftp to be decompressed. So I tried to google and find some solution for gzip decompression. static byte[] Decompress(byte[] gzip) { using (GZipStream stream = new GZipStream(new MemoryStream(gzip), CompressionMode.Decompress)) { const int size = 4096; byte[] buffer = new byte[size]; using (MemoryStream memory = new MemoryStream()) { int count = 0; do { count = stream.Read(buffer, 0, size); if (count > 0) { memory

问题 We're building an online video editing service. One of the features allows users to export a short segment from their video as an animated gif. Imgur has a file size limit of 2Mb per uploaded animated gif. Gif file size depends on number of frames, color depth and the image contents itself: a solid flat color result in a very lightweight gif, while some random colors tv-noise animation would be quite heavy. First I export each video frame as a PNG of the final GIF frame size (fixed, 384x216).

问题 Is there a table that gives the compression ratio of a jpeg image at a given quality? Something like the table given on the wiki page, except for more values. A formula could also do the trick. Bonus: Are the [compression ratio] values on the wiki page roughly true for all images? Does the ratio depend on what the image is and the size of the image? Purpose of these questions: I am trying to determine the upper bound of the size of a compressed image for a given quality. Note: I am not

问题 Mad Kristensen got one down to 00amyWGct0y_ze4lIsj2Mw Can it go smaller than that? 回答1: Looks like there are only 73 characters that can be used unescaped in a URL. IF that's the case, you could convert the 128-bit number to base 73, and have a 21 character URL. IF you can find 85 legal characters, you can get down to a 20 character URL. 回答2: A GUID looks like this c9a646d3-9c61-4cb7-bfcd-ee2522c8f633 - that's 32 hex digits, each encoding 4 bits, so 128 bits in total A base64 encoding uses 6

问题 I need to write a function called compress(S) that takes a binary string S of length less than or equal to 64 as input and returns another binary string as output. The output binary string should be a run-length encoding of the input string. Run-length coding represents an image by a sequence (called a "run-length sequence") of 8-bit bytes: The first bit of each byte represents the bit that will appear next in the image, either 0 or 1. The final seven bits contain the number in binary of

问题 I need to write a function called compress(S) that takes a binary string S of length less than or equal to 64 as input and returns another binary string as output. The output binary string should be a run-length encoding of the input string. Run-length coding represents an image by a sequence (called a "run-length sequence") of 8-bit bytes: The first bit of each byte represents the bit that will appear next in the image, either 0 or 1. The final seven bits contain the number in binary of

问题 I'm currently working on a proxy server where we in this case have to modify the data (by using regexp) that we push through it. In most cases it works fine except for websites that use gzip as content-encoding (I think), I've come across a module called compress and tried to push the chunks that I receive through a decompress / gunzip stream but it isn't really turning out as I expected. (see below for code) figured i'd post some code to support my prob, this is the proxy that gets loaded

问题 I am using tomcat8 and trying to simulate GZIP compression of CSS and JS. I have added the entry in server.xml and follows <Connector port="8088" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" compression="on" compressionMinSize="2048" noCompressionUserAgents="gozilla, traviata" compressableMimeType="text/html,text/xml,text/plain,text/css,text/javascript,text/json,application/x-javascript,application/javascript,application/json" /> And in my html page i have included the

问题 I asked a question earlier about extracting RAR archives in Java and someone pointed me to JUnrar. The official site is down but it seems to be quite widely used as I found a lot of discussions about it online. Could someone show me how to use JUnrar to extract all the files in an archive? I found a little snippet online but it doesn't seem to work. It shows each item in the archive to be a directory even if it is a file. Archive rar = new Archive(new File("C://Weather_Icons.rar"));