.avi Video container or wrapper format created by Microsoft; stores video data that may be encoded in a variety of codecs; typically uses less compression than similar formats such as .MPEG and .MOV. AVI files can be played by various video players, but the player must support the codec used to encode the video data.
.flv Flash-compatible video file exported by the Flash Video Exporter plug-in (included with Macromedia Flash MX) or other program with FLV file support; consists of a short header, interleaved audio, video, and metadata packets; the audio and video data is stored in a similar format to the standard Flash (.SWF) format. The FLV format is an open format that is also supported by non-Adobe/Macromedia programs; FLV files may be exported from QuickTime Pro or other applications that can export to the QuickTime file format.
.swf Animation created by Adobe Flash (formerly Macromedia Flash); can include text as well as both vector and raster graphics; plays in Web browsers that have the Flash plug-in installed; most Web browsers come with a recent version of the Flash plug-in. SWF files are often pronounced "Swiff" files. Flash used to be developed by Macromedia, which was aquired by Adobe Systems in 2005.
.mov
Common multimedia format most often used for saving video or movie files; uses a proprietary compression algorithm developed by Apple Computer; compatible with both Macintosh and Windows platforms.
.wmv Video or audio file based on the Microsoft Advanced Systems Format (ASF) container format and compressed with Windows Media compression; basically an .ASF file that uses a Windows Media Video codec.
.mpg Common video format standardized by the
Moving Picture Experts Group (MPEG); typically incorporates MPEG-1 or MPEG-2 audio & video compression format; often used for creating downloadable movies.
.dvix High-quality, high-compression video codec used for digital video distribution; compresses video to a fraction of the original size with minimal loss in quality; supports video resolutions up to 1080 HD. The DivX format is recognized by some DVD players and other consumer electronics that support DivX.
.mp4 Movie or video clip that uses MPEG-4 compression, a standard developed by the Moving Picture Experts Group (MPEG); commonly used for sharing video files on the Internet. The MPEG-4 video format uses separate compression for audio and video tracks; video is compressed with MPEG-4 video encoding; audio is compressed using AAC compression, the same type of audio compression used in .AAC files.
.asx Shortcut to an audio/video file (typically in .ASF format); references a URL for the location of the actual media
.asf Media container format developed by Microsoft, primarily for streaming media; specifies the structure of the audio or video stream, but not the encoding method; can be compressed using a variety of video codecs.
.3GP Audio and video container format developed by the 3rd Generation Partnership Project (3GPP); designed as a multimedia format for transmitting audio and video files between 3G cell phones and over the Internet; commonly used by mobile phones that support video capture.
Popular Audio File Formats
.mp3 Compressed audio format developed by the Moving Picture Experts Group; uses "Layer 3" audio compression; commonly used to store music files and audiobooks on a hard drive; may provide near-CD quality sound (stereo, 16-bit) in a file roughtly 1/10 the size of a .WAV or .AIF file. The quality of an MP3 file depends largely on the bit rate used for compression; common bit rates are 128 kbps, 160 kbps, and 192 kbps; higher bit rates result in higher quality files that also require more disk space. Supported by most portable music players as well, such as the Apple iPod and Microsoft Zune; can also be played on Symbian OS mobile phones using UltraMP3.
.wma Audio file compressed with Windows Media compression; proprietary format developed by Microsoft, similar to the .MP3 format; can be converted to other more standardized formats; often used for playing music from the Web. Microsoft's Zune portable music player and the Disney Mix Stick MP3 Player can play WMA files; they cannot be played on an iPod.
.wav Standard digital audio file format for storing waveform data; allows audio recordings to be saved with different sampling rates and bitrates; often used to save CD-quality audio. WAV (WAVE) files are similar to .AIF files, but they use a more complex format and are more common on Windows-based systems.
.aif CD-quality audio file, similar to a .WAV file; developed by Apple Computer, but based on the Electronic Arts .IFF format; standard CD audio AIFF files use a sampling rate of 44.1KHz, are 16-bit, and have two channels (for stereo sound).
.m3u Short for "MP3 URL;" contains a playlist of MP3s and other audio or video files; lists the locations of media files in a plain text format; initially used by Winamp, now is used by several media players.
.midi Standard MIDI (Musical Instrument Digital Interface) file; contains music data such as what notes are played, when they are played, how long each note is held, and the loudness, or velocity, or each note. Can be played back using software instruments, but does not contain actual audio data; more commonly seen with a .MID extension.
.mpa Compressed audio file using MPEG Layer I, II or III compression
.ra Audio file created by RealPlayer; may contain audio data or may reference a streaming audio file online; uses a proprietary Real compression algorithm; common format for playing audio clips within a Web browser.
.ram Audio file created with RealPlayer that uses the proprietary Real compression algorithm; may contain audio data or may reference a streaming audio file online. Also seen with a .RA file extension.
.aac Compressed audio file similar to a .MP3 file, but offers several performance improvements; examples include a higher coding efficiency for both stationary and transient signals, a simpler filterbank, and better handling of frequencies above 16 kHz; maintains quality nearly indistinguishable from the original audio source. AAC is the default encoding used by Apple iTunes software.
.4mp Database of audio files organized by 4-MP3, a database manager for storing and searching information on collections of sound files; supported formats include .MP3, .WAV, and .VQF; allows large collections of audio files to be searched and browsed efficiently. 4MP files do not contain actual audio, but only references to the audio files listed in the database.
.iff Universal file format developed by Electronic Arts; may contain text, image, or audio data; used as the basis for several other file formats and is supported by many programs. IFF files are made up of sections of data called "chunks" that are defined with four-letter IDs; the three main chunk types are FORM, LIST, and CAT; FORM specifies the format of the file, LIST includes the properties of the file, at CAT includes the rest of the data; each chunk may contain text, numerical data, or raw data.
.cda Shortcut to a track on an audio CD; plays the referenced track on the CD when opened; therefore, the CD must be in the CD-ROM drive for the shortcut to work correctly.
CDA files do not contain actual audio data; songs "ripped" from an audio CD are usually saved as uncompressed .AIF or .WAV files.
Players, Formats and Basic Codecs (not in any order)
Adobe Media Player>
Adobe Media Player is a desktop media player that offers users to manage and interact with their media content, and allows content publishers to define branding and advertising in and around their content. The Adobe Media Player will be one of the first Adobe AIR applications from Adobe Systems. It was announced at NAB show in Las Vegas and was released in April 2008. More on the Adobe Flash Player from Wikipedia>
