.ASF is a file format created by Microsoft, formerly known as Active Streaming Format or Advanced Streaming Format. ASF is specifically designed for streaming audio and visual content. ASF files are containers for the streaming media, and normally Windows Media Video or Windows Media Audio files are found within them. This format has been superseded by WMV.
An .asf file may contain video and audio, and can also contain metadata in the same way that MP3 files do. This allows the definition of artist, album etc. The file format allows streaming in a similar method to other formats, allowing the user to view the file once a certain amount of bytes have been downloaded. The file continues to download while the user watches. Due to it being designed for streaming, one disadvantage of ASF is that the maximum resolution is a relatively small 352x288.
MPG is commonly associated with video and audio compressions MPEG-1 or MPEG-2. This is designed to compress audio and video to formats that can be downloaded. Movies with this extension are of lower sizes and greater quality, but quality differs from original VCR videos. This file format can run on Mac, Windows and other portable devices.
MPEG-1 is a standard for lossy compression of video and audio. It is designed to compress VHS-quality raw digital video and CD audio down to 1.5 Mbit/s (26:1 and 6:1 compression ratios respectively) without excessive quality loss, making video CDs, digital cable/satellite TV and digital audio broadcasting (DAB) possible. Today, MPEG-1 has become the most widely compatible lossy audio/video format in the world, and is used in a large number of products and technologies. Perhaps the best-known part of the MPEG-1 standard is the MP3 audio format it introduced.