ASF is a media container used by Microsoft Windows Media Player. It was designed for streaming audio and video files online. The container determines the structure of the data stream but not how the data should be encoded. Usually the files encoded by Microsoft developers have the .wma or .wmv extensions, other files have .asf extension. Such files generally have MIME type that allows sending files via the internet. The main feature of the ASF is the ability to stream playback, that is the ability to play a video or audio directly at the time of downloading data over the network.

GIF is a format for the exchange of images. It is a popular format graphics. Capable of storing compressed data without loss of quality in the format of not more than 256 colors. GIF format was developed in 1987 (GIF87a) by company CompuServe for transferring raster images over networks. In 1989, the format has been modified (GIF89a), have been added support transparency and animation.