MPEG is an intialism that actually means Moving Picture Experts Group. It is pronounced (m-peg) not (m p e g). It falls under the guidelines of the International Organization for Standard or ISO. MPEG typically generates visibly improved video quality when compared to other widely available formats, including Video for Windows, Indeo and QuickTime. In the past, MPEG files could not be used on PCs without hardware decoders or codecs for MPEG processing. However, in present times, PCs are able to use codecs found in regular computer software. These programs include RealNetworks, QuickTime or Windows Media Player.
MPEG algorithms essentially compress data to form small portions that are readily transmitted and then decompressed. MPEG accomplishes its high compression rate by storing only the alterations from one frame to another instead of all individual frames. The video information is then encoded utilizing a method known as Discrete Cosine Transform (DCT). MPEG employs a form of lossy compression, as some data is omitted. But the reduction of data is not actually distinguishable to the naked eye.
The major MPEG standards are listed below:
u MPEG-1. This is the most commonly used version of the MPEG-1 standard. It provides a video resolution of 352-by-240 at 30 frames per second (fps). This format will produce video quality that is a little lower than the quality seen in a conventional VCR video format.
- MPEG-2. This will display resolutions of 720×480 and 1280×720 at 60 fps, with complete CD-quality audio. This is adequate for all the widely used TV standards inclusive of NTSC and High-definition television (HDTV). MPEG-2 is typically utilized by DVD-ROMs. MPEG-2 can compress a 2 hour video into as little as a few gigabytes for easier storage. Although decompressing an MPEG-2 data stream needs only satisfactory computer processing abilities, encoding video into MPEG-2 format will necessitate much more computer processing capabilities.
- MPEG-3. was originally developed for use with HDTV but was discontinued and replaced with MPEG-2 for HDTV.
- MPEG-21. Consists of a Rights Expression Language (REL) and a Rights Data Dictionary. Unlike other MPEG standards that detail compression coding methods, MPEG-21 denotes a standard that distinguishes the description of content and also processes for accessing, searching, storing and protecting the copyrights of the particular content being used.
- MPEG-4. Is a graphics and video compression algorithm standard that is founded on MPEG-1 and MPEG-2 and Apple QuickTime technology. Wavelet-based MPEG-4 files are more compact than JPEG or QuickTime files, hence they are designed to transmit video and images over a narrower bandwidth and can combine video with text, graphics and 2-D and 3-D animation layers. MPEG-4 was officially standardized in October 1998 in the ISO/IEC document 14496.
- MPEG-7. This is formally refered to as the Multimedia Content Description Interface. It provides a tool set for fully describing multimedia content. It was developed to be generic and is therefore not associated with a distinct application.