Images with fewer colors will compress more efficiently under LZW compression. A GIF graphic is unable to have more than 256 colors but it can have fewer colors, down to the minimum of two (black and white). The idea is to lessen the amount of colours in a GIF image to the minimum number necessary and to therefore remove stray colors that are not required to represent the image. GIFs are able to hold multiple bitmaps of up to 256 colors each, using LZW (Lempel Zev Welch - a simple form of file compression that removes inefficiencies in the data storage without losing data or distorting the image) compressed raster data to minimize file sizes. The GIF file format was invented by Compuserve for their online service, but they made the specifications publicly available. It uses the lossless data compression technique which reduces the file size without any impact on the quality. It also supports animations and whenever you see a logo or other sharp edged line art then you are probably dealing with the GIF format. This file format supports up to 8 bits per pixel therefore giving an image the ability to contain 256 distinct colours chosen from the 24-bit RGB colour space. The GIF file format is a type of bitmap image and has become popular due to the growth of the internet. What programs can I use to open an AVI file ?.The third optional sub-chunk is identified by the idx1 tag which indexes the offsets of the data chunks within the file. This chunk contains the actual audio/visual data that make up the AVI movie. The second sub-chunk is identified by the movi tag.
This sub-chunk is the file header and contains metadata about the video, such as its width, height and frame rate. The first sub-chunk is identified by the hdrl tag. An AVI file takes the form of a single chunk in a RIFF formatted file, which is then subdivided into two mandatory chunks and one optional chunk. Each chunk is identified by a FourCC tag. Its advatage is a simple architecture, due to which AVI runs on a number of different systems like Windows, Mac, Linux, Unix and is supported by all of the most popular web-browsers.'ĪVI is a derivative of the Resource Interchange File Format (RIFF), which divides a file's data into blocks, or chunks. Create a GIF from a video and share it in seconds. AVI combines audio and video into a single file in a standard container to allow simultaneous playback. Choose a file size and aspect ratio based on where you plan to share your GIF. Developed by Microsoft in 1992, it has become so widespread that many people consider it the de-facto standard for storing video and audio information on PC.