A
AVI , Audio Video Interleave is a multimedia container format introduced by Microsoft in November 1992 as part of its Video for Windows technology. AVI files can contain both audio and video data in a standard container that allows synchronous audio-with-video playback. Like DVDs, AVI files support multiple streaming audio and video, although these features are seldom 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 unofficially called "AVI 2.0".
Advanced Systems Format (formerly Advanced Streaming Format, Active Streaming Format) is Microsoft's proprietary digital audio/digital video container format, especially meant for streaming media. ASF is part of the Windows Media framework. The format does not specify how (i.e. with which codec) the video or audio should be encoded; it just specifies the structure of the video/audio stream. This is similar to the function performed by the QuickTime, AVI, or Ogg container formats. One of the objectives of ASF was to support playback from digital media servers, HTTP servers, and local storage devices such as hard disk drives.
B
Bit rate. In telecommunications and computing, bitrate (sometimes written bit rate, data rate or as a variable R or fb) is the number of bits that are conveyed or processed per unit of time. Bit rate is synonymous with data rate and digital bandwidth. The bit rate is quantified using the 'bits per second' (bit/s or bps) unit, often in conjunction with a SI prefix such as kilo- (kbit/s or kbps), mega- (Mbit/s or Mbps), giga- (Gbit/s or Gbps) or tera- (Tbit/s or Tbps). In digital multimedia, bit rate often refers to the number of bits used per unit of time to represent a continuous medium such as audio or video after source coding (data compression). The size of a multimedia file in byte is the product of the bit rate (in bit/s) and the length of the recording (in seconds), times eight. In case of streaming multimedia, this bit rate measure is the goodput that is required to avoid interrupts. Audio (MP3) • 32 kbit/s — MW (AM) quality • 96 kbit/s — FM quality • 128–160 kbit/s — Standard Bitrate quality; difference can sometimes be obvious (e.g. bass quality) • 192 kbit/s — DAB (Digital Audio Broadcasting) quality. Quickly becoming the new 'standard' bitrate for MP3 music; difference can be heard by few people. • 224–320 kbit/s — Near CD quality. Sound is nearly indistinguishable from most CDs.
BMP file format, sometimes called bitmap or DIB file format (for device-independent bitmap), is an image file format used to store bitmap digital images, especially on Microsoft Windows and OS/2 operating systems. Many graphical user interfaces use bitmaps in their built-in graphics subsystems;[1] for example, the Microsoft Windows and OS/2 platforms' GDI subsystem, where the specific format used is the Windows and OS/2 bitmap file format, usually named with the file extension of .BMP or .DIB.
C
Codec is a device or program capable of performing encoding and decoding on a digital data stream or signal. The word codec may be a combination of any of the following: 'compressor-decompressor', 'coder-decoder', or 'compression/decompression algorithm'.
Compact Disc Digital Audio system, or CDDA. Red Book is the standard for audio CDs. It is named after one of a set of color-bound books that contain the technical specifications for all CD and CD-ROM formats. The first edition of the Red Book was released in June 1980 by Philips and Sony; it was adopted by the Digital Audio Disc Committee and ratified as IEC 908. The standard is not freely available and must be licensed from Philips. At the time of writing, the cost per the relevant Philips order form [1] is US$5,000. As of 2006, the IEC 908 document is now known as IEC 60908 and is also available as a PDF download for $210. The basic specifications state that 1. Maximum playing time is 78 minutes (including pauses) 2. Minimum duration for a track is 4 seconds 3. Maximum number of tracks is 99 4. Maximum number of index points (subdivisions of a track) is 99 with no maximum time limit 5. International Standard Recording Code (ISRC) should be recorded on CD-Rs to appear on the replicated discs
Constant Bit Rate (CBR) is a term used in telecommunications, relating to the quality of service. Compare with variable bit rate. When referring to codecs, constant bit rate encoding means that the rate at which a codec's output data should be consumed is constant. CBR is useful for streaming multimedia content on limited capacity channels since it is the maximum bit rate that matters, not the average, so CBR would be used to take advantage of all of the capacity. CBR would not be the optimal choice for storage as it would not allocate enough data for complex sections (resulting in degraded quality) while wasting data on simple sections. The problem of not allocating enough data for complex sections could be solved by choosing a high bitrate (eg, 256 kbit/s or 320 kbit/s) to ensure that there will be enough bits for the entire encoding process, though the size of the file at the end would be proportionally larger.
D
Dictaphone - the name was trademarked by the Columbia Graphophone Company in 1907, which soon became the leading manufacturer of such devices. Dictaphone was spun off into a separate company in 1923 under the leadership of C. King Woodbridge.After relying on wax cylinder recording through the end of World War II, in 1947 Dictaphone introduced their Dictabelt technology, which cut a mechanical groove into a plastic belt instead of into a wax cylinder. This was later replaced by magnetic tape recording and eventually hard-drive recording. See also voice recorder.
F
FLAC (Free Lossless Audio Codec (FLAC) is a file format for audio data compression. Being a lossless compression format, FLAC does not remove information from the audio stream, as lossy compression formats such as MP3, AAC, and Vorbis do. Like other methods of compression, FLAC's main advantage is the reduction of bandwidth or storage requirements, but without sacrificing the integrity of the audio source. For example, a digital recording (such as a CD) encoded to FLAC can be decompressed into an identical copy of the audio data. Audio sources encoded to FLAC are typically reduced in size 40 to 50 percent. (47% according to their own comparison). FLAC is suitable for everyday playback and audio archival, with support for tagging, cover art and fast seeking. FLAC's free and open source royalty-free nature makes it well-supported by many software applications. FLAC playback support in portable audio devices and dedicated audio systems is limited but growing.[2] Josh Coalson is the primary author of FLAC.
Flash memory is non-volatile computer memory that can be electrically erased and reprogrammed. It is a technology that is primarily used in memory cards, and USB flash drives (thumb drives, handy drive, memory stick, flash stick, jump drive) for general storage and transfer of data between computers and other digital products. It is a specific type of EEPROM that is erased and programmed in large blocks; in early flash the entire chip had to be erased at once. Flash memory costs far less than byte-programmable EEPROM and therefore has become the dominant technology wherever a significant amount of non-volatile, solid-state storage is needed. Examples of applications include PDAs and laptop computers, digital audio players, digital cameras and mobile phones. It has also gained some popularity in the game console market, where it is often used instead of EEPROMs or battery-powered SRAM ("Save RAM", which was not necessarily static RAM) for game save data. Flash memory is non-volatile, which means that it does not need power to maintain the information stored in the chip. In addition, flash memory offers fast read access times (although not as fast as volatile DRAM memory used for main memory in PCs) and better kinetic shock resistance than hard disks. These characteristics explain the popularity of flash memory for applications such as storage on battery-powered devices. Another feature of flash memory is that when packaged in a "memory card", it is enormously durable, being able to withstand intense pressure, extremes of temperature and immersion in water. NAND gate flash uses tunnel injection for writing and tunnel release for erasing. NAND flash memory forms the core of the removable USB interface storage devices known as USB flash drives, as well as most memory card formats available today.
Firmware (FW) in computing, firmware is a computer program that is embedded in a hardware device, for example a microcontroller. It can also be provided on flash ROMs or as a binary image file that can be uploaded onto existing hardware by a user. As its name suggests, firmware is somewhere between hardware and software. Like software, it is a computer program which is executed by a computer. But it is also an intimate and vital part of a piece of hardware, and has little meaning outside of that particular hardware.
FM transmitter is a portable device that plugs into the headphone jack or proprietary output port of a portable audio or video device, such as a media player, CD player, or satellite radio system. The sound is then broadcast through the transmitter, and plays through an FM frequency. Purposes for an FM transmitter include playing music from a device through a car stereo, or any radio without an audio input jack. The FM-transmitter plugs into the audio output of audio devices and converts the audio output into an FM radio signal, which can then be picked up by appliances such as car or portable radios. Most devices on the market typically have a short range of up to 30 feet (9 metres) with any average radio (up to about 75 feet (23 metres) with a very good radio under perfect conditions) and can broadcast on any FM frequency from 76.0 to 108.0 MHz (or 87.9 to 107.9 in the US). Some lower-cost transmitters are hard-wired to the 87.7-91.9 MHz band allocated to educational broadcasts in the United States, or a certain other smaller range of frequencies. FM transmitters are usually battery driven, but some use the cigarette lighter socket in cars, or draw their power from the device itself. They are typically used with portable audio devices such as MP3 or CD players, but are also used to broadcast other outputs (such as that from a computer sound card) throughout a home or other building.
G
GUI (Graphical User Interface) is a type of user interface which allows people to interact with a computer and computer-controlled devices. Instead of offering only text menus, or requiring typed commands: graphical icons, visual indicators or special graphical elements called "widgets", are presented. Often the icons are used in conjunction with text, labels or text navigation to fully represent the information and actions available to a user. The actions are usually performed through direct manipulation of the graphical elements. The term GUI is historically restricted to the scope of flat display screens with display resolutions capable of describing generic information, in the tradition of the research at Palo Alto Research Center (PARC). The term does not apply to other high resolution types of interfaces that are non-generic, such as videogames, or not restricted to flat screens, like volumetric displays.
GIF, Graphics Interchange Format is an 8-bit-per-pixel bitmap image format that was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web due to its wide support and portability. The format uses a palette of up to 256 distinct colors from the 24-bit RGB color space. It also supports animations and allows a separate palette of 256 colors for each frame. The color limitation makes the GIF format unsuitable for reproducing color photographs and other images with continuous color, but it is well-suited for more simple images such as graphics or logos with solid areas of color. GIF images are compressed using the Lempel-Ziv-Welch (LZW) lossless data compression technique to reduce the file size without degrading the visual quality. This compression technique was patented in 1985. Though the relevant patents have all since expired, the controversy over the licensing agreement between the patent holder, Unisys, and CompuServe in 1994 led to the development of the Portable Network Graphics (PNG) standard.
J
JPEG in computing, JPEG (pronounced JAY-peg; IPA: /ˈdʒeɪpɛg/) is a commonly used method of compression for photographic images. The name JPEG stands for Joint Photographic Experts Group, the name of the committee that created the standard. The group was organized in 1986, issuing a standard in 1992, which was approved in 1994 as ISO 10918-1. JPEG is distinct from MPEG (Moving Picture Experts Group), which produces compression schemes for video. The JPEG standard specifies both the codec, which defines how an image is compressed into a stream of bytes and decompressed back into an image, and the file format used to contain that stream. The compression method is usually lossy compression, meaning that some visual quality is lost in the process, although there are variations on the standard baseline JPEG that are lossless. There is also an interlaced "Progressive JPEG" format, in which data is compressed in multiple passes of progressively higher detail. This is ideal for large images that will be displayed whilst downloading over a slow connection, allowing a reasonable preview after receiving only a portion of the data. However, progressive JPEGs are not as widely supported.
L
LAME is a free software application used to encode audio into the MP3 file format. The name LAME is a recursive acronym for LAME Ain't an MP3 Encoder, reflecting LAME's early history when it was not actually an encoder, but merely a set of patches against the freely available ISO demonstration source code.
Liquid crystal display (LCD) is a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. It is often utilized in battery-powered electronic devices because it uses very small amounts of electric power.
M
MP3 player, a digital audio player ("DAP") is a portable consumer electronics device that stores, organizes and plays audio files. Some DAPs are also referred as portable media players as they have image-viewing and/or video-playing support. Most DAPs are powered by rechargeable batteries, some of which are not user replaceable. Listening to music stored on DAPs is typically through earphones connected with a 3.5 mm jack. Digital audio players are generally categorized by storage media: • Flash-based Players – These are non mechanical solid state devices that hold digital audio files on internal flash memory or removable flash media called memory cards. Due to technological advancements in flash memory, these originally low-storage devices are now available commercially ranging up to 32 GB. Because they are solid state and do not have moving parts they require less battery power and may be more resilient to hazards such as dropping or fragmentation than hard disk-based players. Basic MP3 player functions are commonly integrated into USB flash drives. • Hard drive-based Players or Digital Jukeboxes – Devices that read digital audio files from a hard disk drive (HDD). These players have higher capacities currently ranging up to 250 GB. At typical encoding rates, this means that thousands of songs – perhaps an entire music collection – can be stored on one player. • MP3 CD Players – Portable CD players that can decode and play MP3 audio files stored on CDs.
MP3 (MPEG-1 Audio Layer 3) is a digital audio encoding format. This encoding format is used to create an MP3 file, a way to store a single segment of audio, commonly a song, so that it can be organized or easily transferred between computers and other devices such as MP3 players. MP3 uses a lossy compression algorithm that is designed to greatly reduce the amount of data required to represent the audio recording, yet still sound like a faithful reproduction of the original uncompressed audio to most listeners. An MP3 digital file created using the mid-range bitrate setting of 128 kbit/s results in a file that is typically about 1/10th the size of the digital data found on an audio CD. MP3 is an audio-specific format. It was invented by a team of European engineers at Philips, CCETT (Centre commun d'études de télévision et télécommunications), IRT and Fraunhofer Society, who worked in the framework of the EUREKA 147 DAB digital radio research program, and it became an ISO/IEC standard in 1991. The compression works by removing certain parts of sound that are deemed beyond the auditory resolution ability of most people. It provides a representation of pulse-code modulation — encoding audio in much less space than straightforward methods, by using psychoacoustic models to discard components less audible to human hearing, and recording the remaining information in an efficient manner. This is quite different from the principles used by, say, JPEG, an image compression format, which are purely frequency domain based.
MPEG-1 Audio Layer I, commonly abbreviated to MP1, is one of three audio codecs included in the MPEG-1 standard. While supported by most media players, the codec is considered largely outdated, and replaced by MP2 or MP3. For files only containing MP1 audio, the file extension .mp1 is used.
MPEG-1 Audio Layer II (MP2, sometimes Musicam) is an audio codec defined by ISO/IEC 11172-3. An extension exists: MPEG-2 Layer II and is defined in ISO/IEC 13818-3. The file extension for files containing such audio data is usually .mp2. While it has largely been superseded by MP3 for PC and Internet applications, it remains a dominant standard for audio broadcasting as part of the DAB digital radio and DVB digital television standards.
MPEG-4 is a standard used primarily to compress audio and visual (AV) digital data. Introduced in late 1998, it is the designation for a group of audio and video coding standards and related technology agreed upon by the ISO/IEC Moving Picture Experts Group (MPEG) under the formal standard ISO/IEC 14496. The uses for the MPEG-4 standard are web (streaming media) and CD distribution, conversation (videophone), and broadcast television, all of which benefit from compressing the AV stream. MPEG-4 absorbs many of the features of MPEG-1 and MPEG-2 and other related standards, adding new features such as (extended) VRML support for 3D rendering, object-oriented composite files (including audio, video and VRML objects), support for externally-specified Digital Rights Management and various types of interactivity. AAC (Advanced Audio Codec) was standardized as an adjunct to MPEG-2 (as Part 7) before MPEG-4 was issued. MPEG-4 is still a developing standard and is divided into a number of parts. Unfortunately the companies promoting MPEG-4 compatibility do not always clearly state which "part" level compatibility. The key parts to be aware of are MPEG-4 part 2 (MPEG-4 SP/ASP, used by codecs such as DivX, Xvid, Nero Digital and 3ivx and by Quicktime 6) and MPEG-4 part 10 (MPEG-4 AVC/H.264, used by the x264 codec, by Nero Digital AVC, by Quicktime 7, and by next-gen DVD formats like HD DVD and Blu-ray Disc). Most of the features included in MPEG-4 are left to individual developers to decide whether to implement them. This means that there are probably no complete implementations of the entire MPEG-4 set of standards. To deal with this, the standard includes the concept of "profiles" and "levels", allowing a specific set of capabilities to be defined in a manner appropriate for a subset of applications.
Musepack or MPC is an open source lossy audio codec, specifically optimized for transparent compression of stereo audio at bitrates of 160-180 (manual set allows bitrates up to 320) kbit/s. It was formerly known as MPEGplus, MPEG+ or MP+. Development of MPC was initiated in 1997 by Andree Buschmann and later taken over by Frank Klemm, and is currently maintained by the Musepack Development Team (MDT) with assistance from Frank Klemm. Encoders and decoders are available for Microsoft Windows, Linux and Mac OS X, along with plugins for several third-party media players available from the Musepack website, licensed under the LGPL or BSD licenses, and an extensive list of programs supporting the format.
O
Ogg is an open standard for a free container format for digital multimedia, unrestricted by software patents and designed for efficient streaming and manipulation. Ogg is maintained by the Xiph.Org Foundation. The name ‘Ogg’ refers to the file format which can multiplex a number of separate independent free and open source codecs for audio, video, text (such as subtitles), and metadata. The term ‘Ogg’ is often used to refer to audio file format Ogg Vorbis, that is, Vorbis-encoded audio in the Ogg container. Other prominent Xiph codecs that are often encapsulated in Ogg are the video codec Theora, and the human speech audio compression format Speex.
Organic Light-Emitting Diode ( OLED ), also Light Emitting Polymer (LEP) and Organic Electro-Luminescence (OEL), is any light-emitting diode (LED) whose emissive electroluminescent layer is composed of a film of organic compounds. The layer usually contains a polymer substance that allows suitable organic compounds to be deposited. They are deposited in rows and columns onto a flat carrier by a simple "printing" process. The resulting matrix of pixels can emit light of different colors. Such systems can be used in television screens, computer displays, portable system screens, advertising, information and indication. OLEDs can also be used in light sources for general space illumination, and large-area light-emitting elements. OLEDs typically emit less light per area than inorganic solid-state based LEDs which are usually designed for use as point-light sources. A significant benefit of OLED displays over traditional liquid crystal displays (LCDs) is that OLEDs do not require a backlight to function. Thus they draw far less power and, when powered from a battery, can operate longer on the same charge. OLED-based display devices also can be more effectively manufactured than LCDs and plasma displays. But degradation of OLED materials has limited the use of these materials.
P
PlayFX™ is a sound enhancement system developed by Microsoft® and Rockchip®. It was designed to meet the growing requirements of users of media players regarding sound quality control. PlayFX™ allows the user to modify the sound in three ways, each of which is fully adjustable. 3D Headphone – allows you to generate a full 3D sound inside your earphones. PureBass – enables you to feel a deep, extended bass. AutoVolume – will automatically rescale the volume between songs/albums.
PMP - A portable multimedia player (PMP), sometimes referred to as a portable video player (PVP), is a consumer electronics device that is capable of storing and playing digital media. Digital audio players (DAP) that can also display images and play videos are PMPs. Like DAPs, the data is typically stored on a hard drive, microdrive, or flash memory. Other types of electronic devices like cellphones are sometimes referred as PMPs due to their playback capabilities.
T
TFT – a thin film transistor liquid crystal display (TFT-LCD) is a variant of liquid crystal display (LCD) which uses thin film transistor (TFT) technology to improve image quality. TFT LCD is one type of active matrix LCD, though it is usually synonymous with LCD. It is used in televisions, flat panel displays and projectors.
U
Universal Serial Bus (USB) is a serial bus standard to interface devices. USB was designed to allow peripherals to be connected using a single standardized interface socket and to improve plug-and-play capabilities by allowing devices to be connected and disconnected without rebooting the computer (hot swapping). Other convenient features include providing power to low-consumption devices without the need for an external power supply and allowing many devices to be used without requiring manufacturer specific, individual device drivers to be installed. USB supports three data rates: • A Low Speed (1.1, 2.0) rate of 1.5 Mbit/s (187 kB/s) that is mostly used for Human Interface Devices (HID) such as keyboards, mice, and joysticks. • A Full Speed (1.1, 2.0) rate of 12 Mbit/s (1.5 MB/s). Full Speed was the fastest rate before the USB 2.0 specification and many devices fall back to Full Speed. Full Speed devices divide the USB bandwidth between them in a first-come first-served basis and it is not uncommon to run out of bandwidth with several isochronous devices. All USB Hubs support Full Speed. • A Hi-Speed (2.0) rate of 480 Mbit/s (60 MB/s). Experimental data rate: • A Super-Speed (3.0) rate of 4.8 Gbit/s (600 MB/s). The USB 3.0 specification will be released by Intel and its partners in mid 2008 according to early reports from CNET news. According to Intel, bus speeds will be 10 times faster than USB 2.0 due to the inclusion of a fiber optic link that works with traditional copper connectors. Products using the 3.0 specification are likely to arrive in 2009 or 2010.
V
Vorbis is a free and open source, lossy audio codec project headed by the Xiph.Org Foundation and intended to serve as a replacement for MP3. It is most commonly used in conjunction with the Ogg container and is therefore called Ogg Vorbis. Vorbis development began following a September 1998 letter from Fraunhofer Gesellschaft announcing plans to charge licensing fees for the MP3 audio format. Soon after, founder Christopher "Monty" Montgomery commenced work on the project and was assisted by a growing number of other developers. They continued refining the source code until a stable version 1.0 of the codec was released on July 19, 2002. The latest official version is 1.2.0 released on 2007-07-25, but there are some fine-tuned forks, most notably aoTuV, that offer better audio quality, particularly at low bitrates. Work is in progress to merge back those improvements.
W
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 bitstream format method for storing data in “chunks”, and thus also close to the IFF and the AIFF format used on Amiga and Macintosh computers, respectively. It is the main format used on Windows systems for raw audio.
Windows Media Audio (WMA) is an audio data compression technology developed by Microsoft. The name can be used to refer to its audio file format or its audio codecs. It is a proprietary technology which forms part of the Windows Media framework. WMA consists of four distinct codecs. The original WMA codec, known simply as WMA, was conceived as a competitor to the popular MP3 and RealAudio codecs Today it is one of the most popular codecs, together with MP3 and MPEG-4 AAC. In 2003 it came second after MP3 in terms of standalone players supporting it.WMA Pro, a newer and more advanced codec, supports multichannel and high resolution audio.A lossless codec, WMA Lossless, compresses audio data without loss of audio fidelity. And WMA Voice, targeted at voice content, applies compression using a range of low bit rates
If you would like to know more about mp3 & multimedia players, please see also our FAQ section. Based on Wikipedia.