AVI to MP4

Convert your AVI files to MP4 format files to be played on your MP4 player.

What is AVI?
AVI stands for Audio Video Interleave. It is a special case of the RIFF (Resource Interchange File Format). AVI is defined by Microsoft. AVI is the most common format for audio/video data on the PC. AVI is an example of a de facto (by fact) standard. It is a multimedia container format introduced by Microsoft in November 1992, as part of the Video for Windows technology. AVI files contain both audio and video data in a standard container that allows simultaneous playback. Like DVDs, AVI files support multiple audio and video streams, although these features are rarely used. Most AVI files also use the file format extensions developed by the Matrox OpenDML group in February 1996. These files are supported by Microsoft, and are known unofficially as "AVI 2.0".

It is a special case of the Resource Interchange File Format (RIFF), which divides the file's data up into data blocks called "chunks". Each "chunk" is identified by a FourCC tag. An AVI file takes the form of a single chunk in an RIFF formatted file, which is then subdivided into two mandatory "chunks" and one optional "chunk". The whole structure of RIFF file is actually copied from earlier IFF format devised by Electronic Arts in mid-eighties, the only difference being the endianness of integers inside it, and initial FourCC. In fact, a properly written IFF parser for AmigaOS, after correcting for endianness should parse RIFF files just fine.

By way of the RIFF format, the audio/visual data contained in the "movi" chunk can be encoded or decoded by a software module called a codec. The codec translates between raw data and the data format inside the chunk. An AVI file may therefore carry audio/visual data inside the chunks in almost any compression scheme, including: Full Frames (Uncompressed), Intel Real Time Video, Indeo, Cinepak, Motion JPEG, Editable MPEG, VDOWave, ClearVideo / RealVideo, QPEG, MPEG-4, XviD, DivX and others.

What is MP4?
MPEG-4 Part 14, formally, ISO/IEC 14496-14:2003, is a multimedia container format standard specified as a part of MPEG-4. It is most-commonly used to store digital audio and digital video streams, especially those defined by MPEG, but also can be used to store other data such as subtitles and still images. Like most modern container formats, MPEG-4 Part 14 allows streaming over the Internet. The official filename extension for MPEG-4 Part 14 files is .mp4, thus the container format is often referred to simply as MP4.

The MP4 file format contains the media information of an MPEG-4 presentation in a flexible, extensible format which facilitates interchange, management, editing, streaming and presentation of the media. This presentation may be local to the system containing the presentation or via other stream delivery mechanism (a TransMux) while the file format is independent of any particular TransMux. MP4 can be used for MPEG 4 video files, combined video and audio files, or just plain MPEG 4 audio. M4A files contain only MPEG 4 Audio. Apple started using M4A to identify files unprotected by digital rights management; protected QTA_AAC files carry the M4P extension. Apple felt that MP4 was too general (video, video/audio, or audio) and might confuse some media players. Until recently, encoder and player software like Nero and Compaact used .mp4 for audio files while WinAmp 5.02, Apple iTunes, and others used .m4a. Today, most audio software developers allow you to choose the file extension you prefer.

MPEG-4 Part 14 was based on Apple's QuickTime container format. Although MPEG-4 Part 14 still resembles the QuickTime format, it has been improved upon in many different ways.