MPEG, which takes its name from the Motion Picture Experts Group - the international committee of engineers, scientists, and industry representatives responsible for developing and maintaining the standard - is a family of digital compression formats and encoding standards designed to reduce the file size of digital video, animation, and audio data while preserving an acceptable level of quality for the intended application. Since its establishment in 1988, the MPEG committee has developed a succession of increasingly sophisticated compression standards that have become foundational technologies in digital video production, broadcast, distribution, and playback across virtually every platform and medium.
MPEG compression achieves its dramatic file size reductions by exploiting both the spatial redundancy within individual video frames and the temporal redundancy between successive frames in a video sequence. Spatial compression, similar in principle to the compression applied in still image formats such as JPEG, reduces the data required to represent each individual frame by identifying and eliminating redundant information within the frame itself. Temporal compression, which is unique to video compression and represents the most significant source of data reduction in MPEG encoding, analyses the differences between successive frames and encodes only the changes that occur from one frame to the next rather than storing each frame in its entirety as a complete independent image. Because the majority of pixels in any given frame of a video sequence are identical or very similar to their counterparts in the preceding frame, temporal compression can achieve enormous reductions in data compared to storing each frame independently.
The MPEG family encompasses several distinct standards, each developed to address the specific requirements of different applications and quality levels. MPEG-1, the first standard released by the group, was designed for the compression of video and audio at relatively modest data rates suitable for storage on CD-ROM and early digital video applications, and formed the basis of the widely used MP3 audio compression format. MPEG-2 significantly extended the capabilities of the standard to support higher resolutions, better image quality, and the demanding requirements of broadcast television, DVD video, and digital satellite and cable transmission, becoming the dominant compression standard for standard definition and high definition broadcast video distribution for many years. MPEG-4 further advanced the standard with support for very low bitrate encoding suited to internet video streaming and mobile applications, as well as higher quality encoding for professional production use, and introduced the widely adopted H.264 and H.265 video codec standards that have become the dominant compression technologies for high definition and ultra high definition video in the digital era.
In the context of digital photography and camera technology, MPEG compression is directly relevant to the video recording capabilities of digital still cameras, which capture and store video footage using MPEG based compression standards. Most modern digital cameras and smartphones record video in formats based on H.264 or H.265 compression - both of which fall within the MPEG-4 family - storing the compressed video data in container file formats such as MP4 or MOV. The choice of compression standard and bitrate setting used for video recording has a direct influence on the balance between image quality, file size, and the computational demands of editing and processing the recorded footage.