e samples in the data field. 20 The byte eventually given by the formula 1152 X B/(8 or 418 bytes with B = 128 kbit/s. However, the data are then compressed through Huffman coding (see Chapter 9), which is optimized for each individual frame's payload. This does not allow one to predict the actual byte size of the resulting MP3 data field, or the actual compression rate, which is payload dependent. Datafiles Unlike with digital audio, image, and video files, which can suffer lossy compression without loss of perceived quality, most computer data require 100% fidelity in compres- sion processing. Hence, the importance of lossless compression, each with algorithms being ideally suited to the type of source for the most efficient file squeezing. We are now talking about file archiving and packaging, to make the best use of our computer memory space and save time in loading and transmitting files, in particular when it comes to email. The inventory of existing licensed or open-source datafile compres- standards is quite substantial. 21 Most home-computer users, regardless of operating systems, are familiar with the shareware ZIP (file extension .zip and many other vari- ants), which has evolved from a complex IP-litigation history. The 1989-originated root algorithm, PKZIP, is now used in programs with mutually supported formats called WinZip, BOMArchiveHelper, KGB Archiver, PicoZip, Info-Zip, WinRar, 7-Zip, Izarc, and ALZip, to quote only a few.2 Zooming in further, PKZIP is based on the algo- rithms DEFLATE (for compression) and INFLATE (for decompression), which both use a combination of Lempel-Ziv coding (LZ77, see Chapter 10) and Huffman coding (see Chapter 9). Based on DEFLATE, the file archiver GZIP (short for GNU ZIP, with filename extensions .gz, .tgz, .tar.gz, not to be confused with ZIP)24 was developed in the early 1990s as a freeware, circumventing its patented predecessors. Its format includes a ten-byte header (version, timestamp), some optional extra headers (e.g., to include the original file name), 