Glossary |
- What is 3GP - is the MPEG4 based video format used mostly in mobile terminals, such as mobile phones. This file format is designed for 3rd generation mobile devices.
- What is 3ivx - An MPEG-4 toolkit that supports MPEG-4 Video, MPEG-4 Audio and the MP4 File Format.
- What is AAC - Stands for Advanced Audio Coder. An audio-encoding standard for MPEG-2 that is not backward-compatible with MPEG-1 audio.
The MPEG2 audio-encoding standard of the format is not backward-compatible with MPEG1 audio. MPEG2 AAC can produce better audio quality than MP3 using less physical space for the files. MPEG4 AAC can produce better quality and smaller files than MPEG2 AAC. AAC is the audio file format used by Apple in their popular iTunes Music Store. Files may appear on your system with the ".M4A" filename extension.
- What is AC3 - AC3 file, a Dolby Digital audio file, can be found as the standard audio track on Digital Versatile Discs (DVD) and High Definition Television (HDTV). This coder has been designed to take maximum advantage of human auditory masking in that it divides the audio spectrum of each channel into narrow frequency bands of different sizes optimized with respect to the frequency selectivity of human hearing. This makes it possible to sharply filter coding noise so that it is forced to stay very close in frequency to the frequency components of the audio signal being coded. By reducing or eliminating coding noise wherever there are no audio signals to mask it, the sound quality of the original signal can be subjectively preserved.
- What is AIFF - stands for Audio Interchange File Format.
Apple Computer developed this audio file format to store high-quality audio and musical instrument information.
- What is ASF - stands for Advanced Streaming Format.
ASF is a highly compressed file format that contains streaming video, audio. When an ASF file is palyed back, content is deliverd to you as a continuous flow of data. You no longer have to wait for the whole video and audio file to fully download before you start to view them. So, this file format is specially designed to run on networks. When an AVI file is compressed and converted to an .asf file, the file begins playing after only a few seconds. ASF files can be played back with the Windows Media Player (provided the appropriate codecs are installed), streamed with Windows Media Services or optionally packaged with Windows Media Rights Manager.
- What is ASX - stands for Advanced Stream Redirector.
An asx file is used to store information on servers and media files for streaming video and audio over the Internet, such as multimedia web sites. The .asx file is a simple text file that contains server and media information, so you can easily find out the name of the file and server address of the streaming content with a text editor.
- What is AUDIO_TS - UDF file name used for the DVD-Audio directory on a DVD disc volume. DVD-Audio is a separate format from DVD-Video so on a standard DVD-Video is the AUDIO_TS folder empty.
- What is AVI - stands for Audio Video Interleaved and developed by Microsoft.
An AVI file can use different codecs and formats so there is no set format for an AVI file unlike for example standard VCD video which sets a standard for resolution, bitrates, and codecs used. Most commonly used video codecs that use AVI structure are M-JPEG and DivX.
- What is Bitrate - is the average number of bits that one second of video or audio data will consume. Higher bitrate means bigger file size and generally better video or audio quality while lower bitrate means lower file size but worse video or audio quality. Some bitrate examples in common video and audio files: MP3 about 128 kbps (kilobits per second); VCD about 1374 kbps; DVD about 4500 kbps; DV about 25 Mbps (megabits per second).
- What is CD-DA - stands for compact disc digital audio.
It is the original music CD format storing digital PCM data. Defined by the Red Book standard.
- What is CDA - stands for CD Audio.
You can play .cda files only from a CD-ROM. The tracks however, can be ripped to your HDD as a digital audio format like WAV, wma, or MP3 files.
- What is Combo Drive - A DVD ROM drive capable of reading and writing CD-R and CD-RW media. May also refer to a DVD-R or DVD-RW or DVD+RW drive with the same capability.
- What is DVD Chapter (somewhat confusingly referred to as a 'Part' in the parlence of DVD authors) is generally a logical segment of a Title such as a scene in a film or one interview in a set of cast interviews. There can be up to 999 Chapters in one DVD Title.
- What is Codec - stands for Coder/Decoder.
Basically it is a piece of software or a driver that adds a support for certain video/audio format for your operating system. With codec, your system recognizes the format the codec is built for and allows you to play the audio/video file (=decode) or in some cases, to change another audio/video file into that format (=(en)code).
- What is CSS - stands for Content Scrambling System.
In DVD-Video, an encryption scheme designed to protect copyrighted material that resides on a disc by periodically scrambling the data using encryption keys. A tool named Decss can allow users to circumvent it. Although Decss didn't exactly crack the CSS, but instead used leaked decryption keys.
- What is D-VHS - DVHS is a digital recording and playback format for High Definition material. It's based on the existing 1/2" VHS-sized cassettes.
- What is DAT - is used to refer to a certain tape backup format. But in audio/video terminology it normally refers to files that VideoCD has in its SEGMENT or MPEGAV directiories. These DAT files are basically MPEG-1 files with an additional information and certain specific file structure -- they are NOT "real" MPEG-1 files and you need to convert them back to "real" MPEG-1 files in order to edit them even that most of the software players treat them as regular MPEG-1 files.
- What is DivX - It is video encoding technology, released by company called DivXNetworks. The DivX codec is based on the MPEG-4 compression standard. This codec is so advanced that it can reduce an MPEG-2 video (the same format used for DVD or Pay-Per-View) to ten percent of its original size.
- What is DRM - stands for Digital Rights Management.
DRM doesn't mean just basic copy-protection of digital content (like ebooks, MP3s or DivX videos), but it basically means full protection for digital content, ranging from delivery to end user's ways to use the content. somehow DRM system needs to know when the copying is allowed and when not -- users also have rights to make copies to their closest relatives, etc. So, normally this has been solved by allowing "hops" -- original file can be copied, but the copy of the original file cannot be copied any further. Obviously this also causes problems, if user accidentally deletes the original file, but still has the legal copy of the file.
- What is DTS - stand for Digital Theater Systems Digital Sound and is a product of DTS, Inc., DTS is a multichannel audio compression format similar to Dolby Digital/AC3 used in DVD-video discs, DVD-audio, 5.1 channel audio CDs, and some movie theaters. DTS differs from Dolby Digital in that it generally uses higher data rates and many have the opinion that DTS is better quality. DTS can only be on a DVD-video disc if accompanied by a Dolby Digital or LPCM track (for North America ) or mpeg audio and LPCM (European Community) to ensure compatibility, because DVD players are only required to decode those standards in those regions.
- What is DV - stands for Digital Video - video captured to a PC from a digital camcorder.
There are two methods of storing DV video data, that is, type-1 and type-2. Both are stored usually in AVI files. Any DV stored as type-1 cannot be used with VfW-based editors. Microsoft provides DV encoder and decoder filters for DirectShow only, and will not provide support for encoding or decoding DV video data for VfW.
- DV Type-1 Method The native DV interleaved stream that is produced and consumed in I/O with a DV device contains DV compressed video and pulse code modulated (PCM) audio data. This single interleaved stream can be stored in an AVI file as "ivas" stream (for interleaved video/audio stream). Microsoft refers to this format as a type-1 DV AVI file.
Because the type-1 format stores data as a single AVI stream, type-1 DV AVI files are not compatible with VfW. DirectShow, however, easily handles type-1 data streams by routing the streams to a DV Splitter filter that produces a DV-encoded video stream and one or more PCM audio streams for playback or subsequent processing.
- DV Type-2 Method Interleaved DV data can also be split into a single video stream and one to four audio streams within an AVI file. Microsoft refers to this format of storing DV data as type-2. This format has the advantage of being backward compatible with VfW, because it contains a standard video stream and at least one standard audio stream.
The type-2 file format requires a small amount of additional processing to split and multiplex the DV stream during the functions of capture and transmit to IEEE 1394 DV devices.
- What is DVD - stands for Digital Versatile Disc.
DVD is essentially a bigger, faster CD that can hold cinema-like video, better-than-CD audio, and computer data.
- What is DVD-10 - DVD-10 is a double sided single layer DVD. Video DVD, DVD-R/W and DVD+R/W support this format. Effectively this means that DVD-10 is a dual-sided DVD-5 and can hold 8.75 gigabytes of data with 4.38 gigabytes on each side. Two-sided discs need to be flipped over in order to access the other data side. Unfortunately many blank DVD media advertisers mislead customers to believe that these discs are actually blank DVD-9 discs in hope that they could copy their dual-layer discs directly to blank discs.
- What is DVD-18 - is a double sided dual layer DVD which can fit up to 17 GB or 15.9 computer GB which some commercial video DVDs are using today (a DVD-18 is basicly four pressed plastic DVD-5s pressed together, they are not burned).
- What is DVD-5 - is a single sided single layer DVD that stores up to about 4.7 GB = 4 700 000 000 bytes and that is 4.38 computer GigaBytes where 1 kilobyte is 1024 bytes(4 700 000 000B/1024 = about 4 589 843KB/1024 = about 4485MB/1024 = about 4.38GB) . Video DVD, DVD-R/W and DVD+R/W supports this format. Often referred to as "single sided, single layer".
- What is DVD-9 - is a single sided dual layer DVD which can fit up to 8.5 GB or 7.95 computer GB which many commercial video DVDs are using today (a DVD-9 is basicly two pressed plastic DVD-5s pressed together, they are not burned). Video DVD supports this format but DVD-R/W and DVD+R/W does not support this format.
- What is FLAC - stands for Free Lossless Audio Codec. by encoding audio files with FLAC, the quality is exactly the same as the original audio file's quality is. This is exactly unlike the audio formats such as MP3 and WMA work -- these audio formats are called "lossy" and that means that when the original audio is encoded into the lossy audio format, some of the audio data is lost forever and can't be brought back by any means.
- What is ID3 - is a small piece of information stored physically inside the MP3 file (in the beginning or in the end of the file, depends on ID3's version). ID3 tags can contain various information about the MP3, like album name, song name, artist, original artist, genre, composer, releasing year, additional comment fields, etc.. Nowadays ID3s are de facto in audio world and they can be added to most of the audio formats and even to certain video formats in order to provide additional information of the file.
- What is ISO refers also to a CD or DVD image (not picture..) file with an extension of ".iso". The extension comes from the full name of the CD-ROM and DVD-ROM file system specification, ISO 9660. Just like other CD/DVD image formats, ISO is a file that contains full content of the disc, including every single track, directory, file and information about the structure of the disc. Normally ISO files are being used to replicate existing CD/DVD discs, transfer those discs over the network to other location (or to other person) and burn back to CD/DVD which then would be an identical replica of the original disc.
- What is M3U - is a special type of metafile playlist that is used with MP3 files that have an .mp3 file extension. The .m3u files list one MP3 or other media file on each line, normally with full path or URL to the file. If the .m3u file is loaded to an MP3 player, the player normally plays the list of media files in the order they are listed in the playlist (unless options such as "randomize" have been selected in the MP3 player).
- What is M4A - The audio file format used by Apple in their popular iTunes Music Store often appears on your system with the ".M4A" filename extension. M4A can produce better audio quality than MP3 using less physical space for the files.
- What is M4P - format is "protected AAC". It is a format of purchased music that can be listened to only through the iTunes softer or an iPod.
- What is MIDI - stands for Musical Instrument Digital Interface.
A MIDI file doesn't contain actual audio data, but rather contains commands that let MIDI-capable synthesizers re-create a specific musical passage. The MIDI protocol has been used for years as a way for electronic musical instruments (like digital keyboards and sequencers) to communicate with each other.
- What is miniDV is the most popular digital camcorder format at the moment.
miniDV is a video cassette designed for use in miniDV digital camcorders. The picture quality of digital video (DV) recorded on a miniDV cassette is basically identical or better to the quality of DV recorded on a Hi8 or 8mm cassette by a Digital8 camcorder. miniDV can have up to 530 lines of video resolution for some camcorder models. However, miniDV tapes are smaller which allows for smaller camcorders. miniDV tapes are available in lengths of 30 and 60 minutes (plus, recording in LP mode lets you extend total recording time with a 60-minute tape to 90 minutes).
- What is miniDVD is a DVD video written onto a CD-R(W) instead of a DVD disc. miniDVD is also sometimes called cDVD. A miniDVD only fits about 15 minutes of DVD quality video on a 650MB CD-R(W).
- What is MOV - is a file extension used by the QuickTime-wrapped files. QuickTime Content (.mov, .qt), developed by Apple Computer, is a file format for storing and playing back movies with sound. This flexible format isn't limited to Macintosh operating systems. It's also commonly used in Windows systems, and other types of computing platforms.
- What is MP2 - stands for MPEG Audio Layer II or MPEG2 Audio, which used on VCDs, SVCDs and can be used DVDs.
- What is MP3 - stands for MPEG1 (or MPEG2) Audio Layer III. Too often people refer MP3 as MPEG3, which is incorrect, because such format doesn't even exist.
MP3 is a popular compression format used for audio files on computers and portable devices. It is a method to store good quality audio into small files by using psychoacoustics in order to get rid of the data from the audio that most of the humans can't hear.
MP3's bitrates vary from 8kbps to 320kbps. A typical MP3 file encoded at 128kbps is near CD quality. MP3 audio is increasingly being used in video production coupled with various MPEG4 video codecs like divx.
- What is MP3 ID3 Tag - An MP3 ID3 Tag is information stored at the end of an MP3 file. The tag can contain information about the Title/Songname, Artist, Album, Year, Comment, and Genre in version 1 and also Track in version 1.1. A proposed Version 2 is out which would be extendable to include more information and pictures.
- What is MPEG - stands for Moving Picture Expert Group in charge of the development of standards for coded representation of digital audio and video. There are several audio/video formats which bear this group's name, such as MPEG1, MPEG2, MPEG4.
- What is MPEG1 - format is often used in digital cameras and camcorders to capture small, easily transferable motion video clips. It is also the compression format used to create Video CDs. In addition, The well-known MP3 audio format is part of the MPEG1 codec.
- What is MPEG2 - format, a video standard developed by MPEG group, is often used in digital TVs, DVD movies and in SVCDs. It is not a successor for MPEG1, but an addition instead. both of these formats have their own purposes in life. MPEG1 is meant for medium-bandwidth usage and MPEG2 is meant for high-bandwidth/broadband usage.
- What is MPEG4 - the latest compression method standardized by MPEG group, is used for both streaming and downloadable web content, and is also the video format employed by a growing number of portable video recorders. One of the best-known MPEG4 encoders is DivX which since version 5 has been fully standard-compliant MPEG4 encoder.
- What is MPEG7 - doesn't itself offer any new encoding features and it is not meant for representing audio/video content, unlike its siblings MPEG1, MPEG2 and MPEG4. Instead, it offers metadata information for audio and video files, allowing searching and indexing of audio/video data based on the information about the content instead of searching the actual content bitstream.
- What is NTSC - stands for National Television System Committee. NTSC is a color TV standard developed in the United States in 1953 by National Television System Committee. NTSC is used in most of the American continent countries and in various Asian countries. Rest of the world uses either some variety of PAL or SECAM standards. NTSC runs on 525 lines/frame and it's vertical frequency is 60Hz. NTSC's framerate is 29,97 frames/sec.
- What is Ogg - is the umbrella for a group of several related multimedia and signal processing projects that are open source and royalty free. Development of these projects is controlled by Xiph.org. First and best-known project of these is called Ogg Vorbis, a royalty-free audio compression technology.
- What is Ogg Vorbis is an "open-source" digital audio compression format. like MP3, It is a "lossy" compression system, removing frequencies deemed inaudible. Both formats offer variable-bitrate encoding options, for better efficiency. But the algorithms Ogg Vorbis uses to decide which information to discard differ from those used by MP3. Proponents claim that the Ogg Vorbis format outperforms MP3, producing files that are significantly smaller than MP3s of similar sound quality (or files that sound better than similarly sized MP3s).
- What is PAL was introduced in the early 1960's in Europe , stands for Phase Alternating Line. It has better resolution than in NTSC, having 625 lines/frame, but the framerate is slightly lower, being 25 frames/sec. PAL is used in most of the western European countries (except France , where SECAM is used instead), Australia , some countries of Africa , some countries of South America and in some Asian countries.
- What is QuickTime - is a file format for storing and playing back movies with sound. Though developed and supported primarily by Apple Computer, this flexible format isn't limited to Macintosh operating systems. it's also commonly used in Windows systems, and other types of computing platforms. In Windows, QuickTime files usually appear with the ".MOV" filename extension. Since 2002, Apple has started using MPEG4 video encoding on its QT streams, producing much better, if not excellent, video quality. View QuickTime Converter.
- What is RA - stands for Real Audio. RA is a Real Media audio file extension, indicating a file readable by the RealOne Media Player.
- What is RM - stands for Real Media. Real Media is one of the most popular formats for streaming content on the Internet, RealMedia includes the RealAudio codec for sound clips and RealVideo codec for movies. RealAudio and RealVideo files are often given the common RealMedia ".RM" file extension. RealMedia files are often heavily compressed so they can stream over dial-up Internet connections.
- What is RMVB - stands for Real Media Variable Bitrate. RMVB is commonly used to contain Real Video 9 and RA (Real Audio).
- What is SVCD - stands for Super Video Compact Disc (called also SuperVCD or Chaoji VCD).
SVCD is a new CD standard developed in 1998 by Chinese consumer electronics manufacturers, Chinese government and VCD consortium (Sony, Philips, Matsushita and JVC) that allows regular CD to contain 35-60 minutes of video and audio. A SVCD is very similiar to a VCD, although SVCD's video bitrate is normally higher than VCD's. SVCD contains very good quality full-motion MPEG2 video along with up to 2 stereo audio tracks (MPEG1 stereo audio layer II, MPEG2 stereo audio layer II or MPEG2 Multi-Channel 5.1 surround audio) and also 4 selectable subtitles. A SVCD can be played on many standalone DVD Players and of course on all computers with a DVD-ROM or CD-ROM driver with the help of a software based decoder/player.
Just like VCDs (and audio CDs), SVCDs require a specific way how they are burned on the CD -- just sticking all the required files into CD structure doesn't make disc a SVCD compatible. Most of the new CD burning applications support SVCD already, so authoring your own SVCDs should be relatively easy.
- What is SVHS - stands for SuperVHS. SVHS is an improved, high-resolution VHS standard developed by JVC to offer better video quality than the VHS format. SVHS recording can't be played back correctly with VHS videos, unless VHS VCR has something called "super quality playback" that allows playing SVHS tapes.
- What is VCD - stands for Video Compact Disc.
VCD 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 MPEG1 format and stored on the CD in specific format. A VCD can be played on almost all standalone DVD Players and of course on all computers with a DVD-ROM or CD-ROM driver with the help of a software based decoder/player.
VCD is a very popular method for movie distribution in China , Singapore , Malaysia , etc.. Some studios release some of their movies officially for VCD format in Asia . It has almost completely replaced regular VHS format in Asia , because cheap VCD recorders are widely available there. VCD's successor is called SVCD.
- What is VOB - stands for DVD Video OBject. The VOB file is one of the core files found on DVD-Video discs and contains multiplexed Dolby Digital audio (normally AC3 format) and MPEG-2 video. VOB files on a DVD are numbered as follows: vts_XX_y.vob where XX represents the title and Y the part of the title. There can be 99 titles and 10 parts, although vts_XX_0.vob does not contain any video, usually just menu or navigational information. You can find them on a DVD video disc in a subdirectory labelled VIDEO_TS.
- What is VQF - is one of the "alternative" audio compression formats back in 1990s that was aimed to take over MP3 by providing better audio quality than MP3 with lower bitrate. Failed miserabely due various reasons, most notably because of restrictive licensing. Nowadays the only serious alternatives to MP3 are probably Ogg Vorbis and Microsoft's WMA.
- What is WAV - is a standard audio format for Windows operating systems, often used for storing high-quality, uncompressed sound. WAV files can contain CD-quality audio signals. However, CD-quality WAV files require relatively large amounts of memory.
WAV files are probably the simplest of the common formats for storing audio samples. Unlike MPEG audio and other compressed formats, WAVs store samples "in the raw" where no pre-processing is required other that formatting of the data.
The WAV file consists of three "chunks" of information: The RIFF chunk which identifies the file as a WAV file, The FORMAT chunk which identifies parameters such as sample rate and the DATA chunk which contains the actual data (samples).
- What is WMA stands for Windows Media Audio. Windows Media Audio is one of today's most popular Net audio formats. Though not as popular as MP3, WMA tends to outperform MP3 in the area of sound quality, particularly with files encoded at lower bitrates like 64 or 96 Kbps. This performance advantage makes it handy for applications like portable digital audio players, where total play time is limited by a finite amount of internal memory.
- What is WMF - Windows Media Format files are audio/video files encoded with the Windows Media Encoder, providing high quality and media security for streaming and download-and-play applications on PCs, set-top boxes, and portable devices. Windows Media Format comprises Windows Media Audio and Video codecs, an optional integrated digital rights management (DRM) system, and a file container.
- What is WMP - Windows Media Player, a multimedia audio and video player bundled with the Windows Operating System. The player can play many different formats natively including WAV, ASF, WMF, MPEG-1 and can play many types of AVI files if the codec is installed including Divx. WMP can also play MPEG-2 with a third party codec installed (like the ones installed by software DVD players such as WinDVD and PowerDVD).
- What is WMV - stands for Windows Media 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.
- What is XSVCD - stands for eXtended SVCD. XSVCD has same features as SVCD but it is possible to use higher resolution and higher bitrates to get higher video quality. XSVCD burned in "SVCD" Mode on a CD-R or CD-RW can be played on some hardware DVD players and many computers with appropriate software like a software DVD player or a media player with a MPEG-2 codec.
- What is XVCD - stands for eXtended VCD. XVCD has same features as VCD but it is possible to use higher resolution and higher bitrates to get higher video quality. XVCD burned in "VCD" Mode on a CD-R or CD-RW can be played on some hardware VCD or DVD players and many computers with appropriate software.
- What is XviD - is an ISO MPEG4 compliant video codec. It's not a product but an open source project which is developed and maintained by people around the world. XviD, like many other MPEG4 formats, can be played with certain MPEG4 compatible, stand-alone DVD/DivX/XviD players. Please click here for more information about Xvid.
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