WMV: Microsoft’s proprietary compression format for motion video, Windows Media Video is used for both streaming and downloading content via the Internet. Microsoft's Windows Media Player, an application bundled with Windows XP operating systems, lets you playback and manage a range of audio and video file types, including, of course, WMA and WMV.
AVI: AVI stands for Audio Video Interleave and is currently the most common file format for storing audio/video data on the PC. This file format conforms to the Microsoft Windows Resource Interchange File Format (RIFF) specification, which makes it convenient for sharing the file with law enforcement authorities and others that may need to view the video. AVI files (which typically end in the .avi extension) require a specific player that may be included with your Web browser.
MP4: MPEG-4 Part 14 or *.mp4, is a file format (a so called container) specified as a part of the ISO/IEC MPEG-4 international standard. It is used to store media types defined by the ISO/IEC Moving Picture Experts Group, and can be used to store other media types as well. It is, or will be, typically used to store data in files, though it will be used in data streams and possibly in other ways.
3GP:3gp is a file format which is used in mobile phones to store media (audio/video). This file format is a simpler version of "ISO 14496-1 Media Format". MOV (used by QuickTime) is also a format which follows similar file format. This format can only carry video encoded as MPEG-4 or H.263. Audio is stored in AMR-NB or AAC-LC formats.
AAC: AAC stands
for two things: either MPEG-2 Advanced Audio Coding or MPEG-4
Advanced Audio Coding and as its full name suggests, it
is either an MPEG-2 or MPEG-4-based audio format.
The MPEG-2 version of the format is also often called as
MPEG-2 NBC as in Non-backwards compatible, but the correct
name that should be used, is the AAC. The NBC name comes
from the fact that unlike older MPEG audio encoding methods,
it is not backwards compatible (for example, MP3 is backwards
compatible to MP2) to older MPEG audio formats.
MPEG-2 AAC produces better audio quality than MP3 using
less physical space for the files and MPEG-4 AAC produces
better quality and smaller files than MPEG-2 AAC..
MP3:MP3 is an acronym for MPEG-1 or MPEG-2 audio layer 3. MP3 is the file extension for MPEGaudio layer 3. Layer 3 is one of three coding schemes (layer 1, layer 2 and layer 3) for the compression of audio signals. Layer 3 uses perceptual audio coding and psychoacoustic compression to remove all superfluous information (more specifically, the redundant and irrelevant parts of a sound signal. The stuff the human ear doesn't hear anyway).
Moving Pictures Expert Group. A working group of ISO/IEC
in charge of the development of standards for coded representation
of digital audio and video.
MPEG is not an acronym for any standard, it is the acronym
for the group who develops these standards! For various
standards, take a look at MPEG-1 or MPEG-2.
MPEG-1 : Audio and video
compression format developed by MPEG group back in 1993.
Official description: Coding of moving pictures and associated
audio for digital storage media at up to about 1,5 Mbit/s.
MPEG-1 is the video format that has had some extremely
popular spin-offs and sideproducts, most notably MP3 and
MPEG-1's compression method is based on re-using the existing
framematerial and using psychological and physical limitations
of human senses. MPEG-1 video compression method tries to
use previous frame's information in order to reduce the
amount of information the current frame requires. Also,
the audio encoding uses something that's called psychoacoustics
-- basically compression removes the high and low frequencies
a normal human ear cannot hear.
MPEG-2 : A video standard
developed by MPEG group. MPEG-2 is not a successor for MPEG-1,
but an addition instead -- both of these formats have their
own purposes in life; MPEG-1 is meant for medium-bandwidth
usage and MPEG-2 is meant for high-bandwidth/broadband usage.
Most commonly MPEG-2 is used in digital TVs, DVD-Videos
and in SVCDs.
RM: A Real Media movie file will typically store a movie clip. It's generally supported by many different platforms.
M4a: MPEG-4 Part 3 (formally ISO/IEC 14496-3) is, as the name suggests, the third part of the ISO/IEC MPEG-4 international standard. It specifies audio coding methods.
WMA:Windows Media Audio (WMA) is a proprietary compressed audio file format developed by Microsoft. It was initially a competitor to the MP3 format, but with the introduction of Apple's iTunes Music Store, it has positioned itself as a competitor to the Advanced Audio Coding format used by Apple. It is part of the Windows Media framework...
ASF: Advanced Streaming Format (formerly Active Streaming Format). A Microsoft file and data stream format for multimedia data including audio, video, still images, and other data types. Also referred to as Windows Media format. The ASF specification defines the structure of complex, synchronized object data streams. Any object can be placed into an ASF data stream, including audio and video data objects, scripts, ActiveX controls, and HTML documents. ASF is optimized for limited-bandwidth situations.
VOB: Video Object, a file on a DVD-Video disc containing MPEG video, audio and navigation dataA VOB file (short for Video Object) is a DVD file that contains the actual Video, Audio, Subtitle and Menu content in stream form.
Dat: DAT (Digital Audio Tape) is a standard medium and technology for the digital recording of audio on tape at a professional level of quality. A DAT drive is a digital tape recorder with rotating heads similar to those found in a video deck. Most DAT drives can record at sample rates of 44.1 KHz, the CD audio standard, and 48 KHz. DAT has become the standard archiving technology in professional and semi-professional recording environments for master recordings
WAV: WAV (or WAVE), short for Waveform audio format, is a Microsoft and IBM audio file format standard for storing audio on PCs. It is a variant of the RIFF bit stream format method for storing data in "chunks", and thus also close to the IFF and the AIFF format used on Macintosh computers. It takes into account some peculiarities of the Intel CPU such as little endian byte order. The RIFF format acts as a "wrapper" for various audio compression codecs.
generic brand iPod refers to a class of portable digital
audio players designed and marketed by Apple Computer. (Hewlett-Packard
also markets the product under the name Apple iPod + HP.)
Devices in the iPod family offer a simple user interface
designed around a central scroll wheel. Most iPod models
store media on a built-in hard drive, while a lower-end
model, iPod shuffle, relies on flash memory.
PPC: A Pocket PC is a computer in a handheld size that runs a variation of the operating system Windows CE. It has many capabilities of modern desktop PCs. Currently there are thousands of applications for Pocket PC, many free. Some of these devices, running Microsoft Windows Mobile 2003 Phone Edition, also include mobile phone features. Pocket PCs can also be used with many other add-ons like GPS receivers or barcode readers.
Archos: Archos - founded in 1988 (FOREX ticker ACOSF) is a France-based company that specializes in portable media players and storage devices.
Creative Zen: The Creative Zen is a line of digital audio players produced by Creative Labs and a branch off the earlier Creative Nomad brand (the other branch being the Creative MuVo series). Some models feature a touch-pad interface similar to the Apple iPod, but using a vertical strip rather than a circle. They are capable of playing WMA, MP3 and WAV audio files, and the players are based on miniature hard disk drives rather than flash memory.
(full name iRiver Limited): daughter company to Reign COM,
is a consumer electronics developer founded in 1999 and
is located in Seoul, Korea. It is most renowned for producing
unique portable digital audio players (aka "MP3 players")
and video players with more features than others on the
market. Common features on iRiver products are driverless
operation, FM tuner and recording capabilities.
RealAudio: is a proprietary audio format developed by Real Networks. It is especially designed to conform to low bandwidths, and it can be used as a streaming audio format, i.e. played at the same time as its downloaded. Many radio stations use RealAudio to stream their programming over the internet in real time. The first version of RealAudio was released in 1995. As of 2005, the current version is RealAudio 10.
VCD: VCD stands for VideoCD (version 2.0 to be more specific). VideoCD is a standard developed in early 1990's that allows regular CD to contain 74 minutes of video and audio. Both, video and audio, are encoded in MPEG-1 format and stored on the CD in specific format.
DivX: DivX is a digital video compression format based on the MPEG-4 technology. DivX files can be downloaded over high-speed lines in a relatively short time without sacrificing the quality of the digital video. Often used on the Internet to exchange video files.
XviD: XviD is an open source MPEG-4 video codec. Originally based on Open DivX, XviD was started by a group of volunteer programmers after the Open DivX source was closed.