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Python Imaging Library is a free and open-source additional library for the Python programming language that adds support for opening, manipulating, and saving many different image file formats. It is available for Windows, Mac OS X and Linux. The latest version of PIL is 1.1.7, was released in September 2009 and supports Python 1.5.2–2.7. [3]
bzip2 is a free and open-source file compression program that uses the Burrows–Wheeler algorithm.It only compresses single files and is not a file archiver.It relies on separate external utilities for tasks such as handling multiple files, encryption, and archive-splitting.
Three types of pictures (or frames) are used in video compression: I, P, and B frames. An I‑frame (intra-coded picture) is a complete image, like a JPG or BMP image file. A P‑frame (Predicted picture) holds only the changes in the image from a previous frame. For example, in a scene where a car moves across a stationary background, only the ...
Composite image showing JPG and PNG image compression. Left side of the image is from a JPEG image, showing lossy artefacts; the right side is from a PNG image. In the late 1980s, digital images became more common, and standards for lossless image compression emerged. In the early 1990s, lossy compression methods began to be widely used. [14]
MPEG-2 is used in Digital Video Broadcast and DVDs. The MPEG transport stream, TS, and MPEG program stream, PS, are container formats.. MPEG-2 (a.k.a. H.222/H.262 as was defined by the ITU) is a standard for "the generic coding of moving pictures and associated audio information". [1]
MPEG Program Stream (MPEG-1 Part 1 (essentially identical) and MPEG-2 Part 1) 00 00 01 B3 ␀␀␁³: 0 mpg mpeg MPEG-1 video and MPEG-2 video (MPEG-1 Part 2 and MPEG-2 Part 2) 66 74 79 70 69 73 6F 6D: ftypisom: 4 mp4 ISO Base Media file (MPEG-4) 66 74 79 70 4D 53 4E 56: ftypMSNV: 4 mp4 MPEG-4 video file 78 01: x␁ 0 zlib No Compression (no ...
Most lossless compression programs do two things in sequence: the first step generates a statistical model for the input data, and the second step uses this model to map input data to bit sequences in such a way that "probable" (i.e. frequently encountered) data will produce shorter output than "improbable" data.
For example, the above 192×128 PNG (Portable Network Graphics) image has a file size of 166 bytes. When converted to a 192×128 PPM image, the file size is 73,848 bytes. Filesize reduction factor 100 or so when converting to png is typical if the image is a line drawing; if the image is a photo, it is best converted to jpeg, which yields a ...