The MPEG-4 (MP4) video format, once overshadowed by the dominant AVI and MPEG-1 codecs, stormed to prominence for its compatibility with iPods and other portable video devices. The format works on both Macs and PCs.
The Moving Picture Experts Group (MPEG) defined the MPEG-4 format after having already released the successful MPEG-1 and MPEG-2 formats. The format became a popular development standard in 2000 and first appeared publicly when Apple included it with a new version of QuickTime in 2002.
MPEG designed the MP4 format to scale for all sorts of uses. While high-bandwidth users employ the format for swapping high-definition video online, the format can also be used for saving small files for cell phone streaming and sharing. Additionally, the MP4 container gained traction for its ability to play back on video-enabled iPods.
Improved File Size
MP4 improves on earlier MPEG products by improving compression technology. In comparison to MPEG-1 and MPEG-2 files, MP4s compress video and audio much more efficiently, making them well-suited for both sharing and playback on devices with small hard drives. The MP4 format offers a more efficient alternative to bulky PC formats like the AVI and WMV.
Advanced Audio Coding
MP4 files use Apple's Advanced Audio Coding (AAC) codec, which also improves on older audio types like the prevalent MP3 container. Apple's iTunes software uses AAC as its standard format for ripping CDs, and Apple supports the format as the successor to the popular MP3 audio container.
A later development for the MP4 format, the H.264 codec advances the MP4 format by greatly increasing the efficiency of high-resolution content. H.264 files can quadruple the resolution of an MP4 at the same file size. However, many desktop video jukeboxes are not equipped to play back H.264 files.