MPEG-4 Demystified

The MPEG-4 format is really a suite of standards with many parts. Each part offers a set of standards for aspects such as audio, video, and file formats. The standard was first introduced in 1998, but continues to evolve with important new changes. MPEG is an acronym for the ISO/IEC Moving Picture Experts Group, which serves as the governing body for the format.

The two most common parts of MPEG-4 are part 2, which is used in codecs such as DivX and QuickTime 6, and H.264, which is part of QuickTime 7 and QuickTime X as well as Blu-ray Discs. We’ll explore the newer H.264 in a moment, but lets first look at the common .mp4 file that is often used for the web.Note that certain players can handle both types of MPEG-4 video, while many newer devices prefer H.264 video.

Many compression tools offer the more plainly labeled MPEG-4 option. This generally means that the older MPEG-4 part 2 Simple Profile specs are being followed. This ensures greater compatibility with QuickTime 6. The format is also more likely to play using other web-based players such as RealPlayer and the open-source VLC media player. Some podcasters favor this format if they are targeting a user-base of running older computer operating systems. While the format does offer broader support, it does not offer the same level of quality of the newer H.264 format.

The H.264 format is an extension of the MPEG family and is also called MPEG-4 Part 10, or AVC (Advanced Video Coding). This format is broadly used outside of podcasting and web video including uses for broadcast television and Blu-ray Discs. The format was first drafted in 2003, and saw widespread adoption by 2005. H.264 video wrapped in an MPEG-4 container is the preferred format of Apple, as it is used for both movie trailers on Apple’s website and TV shows and movies available for sale it the iTunes Store.

Support for H.264 extends beyond Apple. In 2005, Sony added complete support to the PlayStation Portable line. In 2006, Microsoft launched the Zune portable media player, which included both MPEG-4 and H.264 support. In 2007, YouTube began encoding all uploaded videos to both their standard player and H.264. This move was to broaden the reach of YouTube videos to the iPhone, iPod touch, and iPad models. Additionally, Adobe Media Player released in 2008 also supports H.264 in addition to Flash video.