The following is an article from my friends at WorshipFilms.com that I thought would be of interest and benefit for you. Enjoy!
Today’s digitized videos come in an array of file formats. Let’s take a look at the most popular ones, and briefly discuss their differences..AVI files. AVI stands for audio/video interleaved. This file format is the most popular computer video format, and it is defined by Microsoft. The file sizes tend to be large compared to some of the other formats. These files will play in most of the popular media players. Generally, they are used to edit video or when a high resolution version of the video is needed.
.MPG, .M1V, .M2V files. MPG (or MPEG) stands for Moving Picture Experts Group. This file type utilizes standards that have been, and are being, developed by the Moving Picture Experts Group. They are a common file type and are generally much smaller in size than .AVI files.
.MPG most commonly denotes a file with MPEG-1 compression. The most common resolution for this file type is 352×240, but other resolutions may be used (most of the MPEG-1 files produced by WorshipFilms are 800×600). .M1V usually denotes a video with MPEG-1 compression that does not contain any audio. MPEG-1 files will play in almost any media player. They are generally used when limiting the file size is the main objective.
One confusing element is that .MPG can also denote a file that utilizes MPEG-2 compression. These files are generally higher in resolution (most commonly 720×480), and are often used in the creation of DVDs. .M2V generally denotes a video with MPEG-2 compression that does not contain any audio. The file size of MPEG-2 files is generally larger than MPEG-1 files. MPEG-2 files will only play in media players that have a MPEG-2 video codec installed.
.MOV, .QT files. These files extensions denote a Quicktime media file. Apple Computer developed this file type for the creation and viewing of media content. Generally, most media players will play a Quicktime file that is version 2.0 or earlier, but later versions require player software that is proprietary to Apple. File sizes are generally comparable or slightly larger when compared to MPEG-1 files (depending on compression settings).
.WMV files. WMV stands for Windows Media Video, and refers to a video codec set developed by Microsoft. In earlier versions, Microsoft utilized a form of MPEG-4 technology in developing this codec, but later versions has relied more on Microsoft’s own technology. It is a widely used file format on the internet because of its relatively small file size, and is now used in other media players beyond Windows Media Player.
.ASF files. ASF is short for Advanced Streaming Format. It is a very compressed format that contains streaming audio, video, slide shows, and synchronized events. It provides a continuous stream of data, so that even lengthy videos begin playing almost immediately. It is not necessary for the entire file to download first. This is a popular internet file format, especially for online seminars or other lengthy subjects.
.RM files (also .RA or .RAM). A .RM file is a Real Media file, which (of course) is played in Real Media Player. These files are generally intended to be used as streaming files, and cannot be played in other media players.
.MP4 files (or .M4V). MP4, or MPEG-4 is a format developed by the Motion Picture Experts Group that allows you to combine multiple media streams into one file. Initially, the MPEG-4 format looked a lot like the Apple Quicktime format, but has since been significantly changed and improved upon. It is an end-user format that is used most often for streaming applications and mobile devices (PDA’s, cell phones, etc.). The great appeal of this format is its general quality level in relation to its small file size.
Hopefully, this will serve as a basic reference for you on video file formats, and help you to more quickly identify file types in the future.