Fx Video Converter: More Information

Digital movies, like all other computer files, contain a file name and a file extension. The file extension, the characters following the last period in the file name, tell the operating system what software to use to open that particular file. The first few bytes of the digital movie file, called the header, tells the software how to open the movie including what codec* to use.

Herein lies the rub.
If a movie was created using a codec that you don't have or it was written specifically for a player that you don't have you can't see it.

Movie Formats and File Extensions
The format of a digital movie is determined by the standard to which the codec adheres and not by the file extension thus not particularly useful to the computer user who has a movie that won't play.

The original audio video interleaved format (AVI) became complicated from it's birth because the codec was a separate, custom component and many early AVI files were created with proprietary file extensions that married the file to a proprietary player.

With the Moving Pictures Expert Group MPEG-1 standard we saw two new file extensions for AVI files: MPG for operating systems that supported four character file extensions and MPEG for operating systems that supported four character file extensions. To make matter worse, the MPEG Committee's Layer-1 and Layer-2 audio standards were soon carrying MP2 and MP3 file extensions.

The MPEG-4 standard was a huge breakthrough for AVI file compression and Microsoft's MPEG-4 codec was the vanguard for pay-per view video disks using the DIVX file extension. The codec was quickly hacked however and the DIVX movies were pirated sending the industry back to the drawing board. The existing DIV and DIVX file extensions are used for the proprietary AVI files compressed using the MPEG-4 codec produced by DivX Networks. DivX files can usually be played by most players.

Microsoft created two more MPEG-4 codecs using the AVI file extension, then switched to the Windows Media format. The file extensions for Windows media are usually WMV or WMA.

Real Media and Apple have held their MPEG-4 AVI files tighter than has Microsoft and neither uses the AVI file extension. Real uses RM for the original type RMVB for variable bitrate files and a few other combinations that tell Real Player what to do. Apple began using AVI, then switched to MOV, then to QT with numerous iterations of the codec making it the most difficult to identify.

The MPEG-2 standard was focused on Super Video CD and DVD disks where the AVI files are sometimes encoded to include chapter information and additional data such as comments or languages. MPEG-2 files when not written to a disk are usually named using the MPG file extension.

Fx Video Converter: Screenshots