.asf Video File Format
According to the Wikipedia page on the subject, the "Advanced Systems Format (formerly Advanced Streaming Format, Active Streaming Format) is Microsoft's proprietary digital audio/digital video container format, especially meant for streaming media. ASF is part of the Windows Media framework."
ASF files use streaming technology, enabling viewers to watch portions of video footage without downloading the entire file, a nice feature that allows viewers to review footage after only a few seconds.
ASF files also use temporal compression, which reduces the amount of data stored within a sequence of frames by employing key frame technology. Rather than storing every pixel in each frame, temporal compression stores a key frame, the only the information which is changing between key frames. Quality of the footage can be significantly lower than progressive encoding formats as a result of temporal compression being used. Temporal compression also has the drawback of not allowing future editing of the file.
Other: