16:9
Aspect ratio most commonly known as widescreen or letterbox. It is wider than the standard 4:3 aspect ratio. 16:9 supporters state that the wider picture corresponds much better to the human visual field than the almost square 4:3.



2:2 pulldown
The process of transferring 24-frame-per-second film to video by repeating each film frame as two video fields. When 24-fps film is converted via 2:2 pulldown to 25-fps 625/50 PAL video, the film runs 4 percent faster than normal.



2:3 pulldown
The process of converting 24-frame-per-second film to video by repeating one film frame as three fields, then the next film frame as two fields



3:2 pulldown
An uncommon variation of 2-3 pulldown, where the first film frame is repeated for 3 fields instead of two. Most people mean 2:3 pulldown when they say 3:2 pulldown.



3GP
The mpeg4 based video format used in mobile terminals, like cell phones.



3ivX
3ivx is an MPEG-4 toolkit that supports MPEG-4 Video, MPEG-4 Audio and the MP4 File Format.
http://www.3ivx.com/technology/index.html



42
A Mac program that goes directly from DVD to various video formats including VCD, SVCD, and Divx.



4:1:1
4:1:1 Sampling
A ratio used to describe the sampling frequency of a digitized signal. The ratio describes luminance as being sampled 4 times at 3.37 MHz, while color is sampled 1 time at 3.37 MHz in each of it's separate parts. DV, DVCAM and DVCPRO25 use 4:1:1 color sampling. Formulated as: Y (luminance) is sampled at 13.5 MHz (or 3.37 x 4), R-Y (color) is sampled at 3.37 MHz (or 3.37 x 1), B-Y (color) is sampled at 3.37 MHz (or 3.37 x 1) equals 4:1:1.



4:2:2, 4:4:4 and 4:4:4:4
Put simply 4:4:4 and 4:2:2 terms are descriptions of the sample formats used in digital video. In the early 80's tests were done to determine the sample formats and rates for digital video. The eventual sample structure used for SDI video ended up being 4 times the base sample rate chosen.
The first 4 in the 4:2:2 term is for luminance or the black and white information, and this is where most of the picture detail is. Early tests in television human vision discovered a greater sensitivity to black and white information, while the color is filled in with less detailed areas of the human eye. This means you can reduce the color information and your eye cannot really tell. This is what the 2:2 part of 4:2:2 is for. It means the red and blue channels of the video signal are half the bandwidth of the luminance information. Green is not sent, as you can calculate green from red, blue and luminance information.
This color bandwidth reduction has been used for years in broadcast color television, and in fact the color bandwidth of 4:2:2 is much higher than composite video. This all adds up to 4:2:2 being compatible with black and white or composite television, as the color and luminance information is sent separately, while only 2/3 of the data rate is required for about the same visual quality video.
4:4:4 video is similar, but this time all the color information is sent. RGB computer graphics are really 4:4:4. The 4:4:4:4 format adds a key channel.



4:3
Traditional nearly square aspect ratio used for most current analog television screens and IMAX movie theater screens. This aspect ratio will slowly be phased out in favor of the wider, more panoramic and movie-like 16:9 ratio. Video displays using a 4-by-3 ratio display images 4 units wide (horizontal measure) by 3 units tall (vertical measure).

The 4:3 ratio performs fine for television programming, which was designed for it, but it creates problems with movie material originally designed for theater release. The movies are created with a wider, more rectangular aspect ratio (16:9 or wider) in order to create a larger viewing surface and bring the viewer more into the film. On a traditional 4-by-3 aspect ratio display, these movies must be letterboxed or cut down in size (pan & scan).



5.1 Audio
In contrast to the Stereo sound system and conventional Surround Systems, this sound system offers five separate full band audio signals: Left, middle, right, rear left, rear right. An additional subwoofer (LFE) channel is also provided.



525/60
The scanning system of 525 lines per frame and 60 interlaced fields (30 frames) per second. Used by the NTSC television standard.



625/50
The scanning system of 625 lines per frame and 50 interlaced fields (25 frames) per second. Used by PAL and SECAM television standards.





A
AAC
Advanced audio coder. An audio-encoding standard for MPEG-2 that is not backward-compatible with MPEG-1 audio.



AC3
See Dolby Digital. A .ac3 file is a Dolby Digital audio file.



AfroPic
A mac video conversion program. It can easily demux files and has various other functions available.



AIFF
Macintosh AIFF Resource ( .aif, .aifc, .aiff) Audio Interchange File Format (AIFF) is an audio file format that was developed by Apple Computer. This format may be used to store high-quality sampled audio and musical instrument information.



Aliasing
A distortion (artifact) in the reproduction of digital audio or video that results when the signal frequency is more than twice the sampling frequency. The resolution is insufficient to distinguish between alternate reconstructions of the waveform, thus admitting additional noise that was not present in the original signal.



Anamorphic
Process where a “wide” video image (typically in a 16:9 widescreen format) is compressed or squeezed horizontally to fit a more narrow video display standard but expands to full size when played over a wide video display.

Letterboxing an image enables the viewer to see the entire widescreen presentation of a movie as it was intended and as it was shown in the theater. However, in order to fit a “wide” image in a “narrow” television, the wide image must be centered in the screen with black bars above and below it (in order to fit a wide image in a narrow screen, the width must match the width of the narrow display so the height of the image is necessarily less than that of the more narrow and square video display). While this method allows the user to see the entire image as it was meant to be seen (narrow 4:3 aspect ratio television sets normally show pan & scan movies), the image loses some horizontal resolution to the black bars.

While not much can be done about this on standard 4:3 televisions, there are wider 16:9 displays, which can show an entire movie image with no bars thus allowing the picture to fill the screen. To take advantage of this, a movie can be distributed in a squeezed anamorphic format without black bars. On a more square 4:3 television this results in an image which seems tall and pinched with actors looking too narrow and objects distorted. However, when played on a widescreen display, the picture is stretched out to its proper width resulting in a widescreen image with no bars and the maximum possible resolution. This technique is being used primarily with DVDs to provide superior quality video to users of widescreen televisions. DVDs featuring this anamorphic version allow a user to watch the image in a letterboxed or pan & scan format on their traditional more square 4:3 televisions when this is selected while allowing users with widescreen televisions to enjoy the full benefit of their displays. AudioVideo101 - Ultimate Guide



Angle
A scene recorded from different viewpoints. Each angle is equal in time length and an Angle Block may contain up to nine (9) angles.



Antialiasing
Smoothing or reducing disturbing picture effects. By means of calculation of intermediate values along the sharp edges of types and graphics, these edges can be smoothed out, thus generating a smoother picture. The pixel structure along tilted or bent edges is mixed with the surrounding colors. When creating DVD Menu text, antialiasing must not be used.



Artifact
An unnatural effect not present in the original video or audio, produced by an external agent or action. Artifacts can be caused by many factors, including digital compression, film-to-video transfer, transmission errors, data readout errors, electrical interference, analog signal noise, and analog signal crosstalk. Most artifacts attributed to the digital compression of DVD are in fact from other sources. Digital compression artifacts will always occur in the same place and in the same way. Possible MPEG artifacts are mosquitoes, blocking, and video noise.



ASF
Advanced Streaming Format (ASF): This file format stores audio and video information, and it is specially designed to run on networks like the Internet. This file format is a highly flexible and compressed format that contains streaming audio, video, slide shows, and synchronized events. When you use .asf files, content is delivered to you as a continuous flow of data. You no longer have to wait for your audio and video files to fully download before you start to view them. When an Audio Video Interleave (.avi) file is compressed and converted to an .asf file, the file begins playing after only a few seconds. The file can be unlimited in length and can run over Internet bandwidths. Microsoft ASF information - MS Sample



Aspect Ratio
The width-to-height ratio of an image. A 4:3 aspect ratio means the horizontal size is a third again wider than the vertical size. Standard television ratio is 4:3 (or 1.33:1). Widescreen DVD and HTDV aspect ratio is 16:9 (or 1.78:1). Common film aspect ratios are 1.85:1 and 2.35:1. Aspect ratios normalized to a height of 1 are often abbreviated by leaving off the :1.



ASPI
ASPI stands for Advanced SCSI Programming Interface. Originally developed by Adaptec. It is a software layer that enables programs to communicate with SCSI and ATAPI devices(CD and DVD Drives and other storage peripherals). Bart's page about ASPI.



ASV
(Audio Still Video) A still picture on a DVD-Audio disc.



ASX
Advanced Stream Redirector (ASX): When you use .asx files, you are directed to streaming media content, usually on multimedia Web sites. The .asx files are simple text files that contain server and media information. They are metafiles (a file that provides information about Windows Media files and their presentation) that are similar to Windows Media Redirector (.wvx) files.

If you want to find out more about the streaming content you can open an ASX file in a text editor and often find the filenames of the actual streaming content (often with an .asf extension denoting an ASF file).



ATA
Advanced Technology Attachment or called Parallel ATA is a disk drive implementation that integrates the controller on the disk drive itself. There are several versions of ATA:
ATA, also called IDE.
ATA-2, also called EIDE.
Ultra-ATA, also called Ultra-DMA, ATA-33, and DMA-33.
ATA/66ATA/100
http://www.webopedia.com/TERM/A/ATA.html

See SATA.



ATAPI
Advanced Technology Attachment Packet Interface is a interface to support CD Drives and DVD Drives using the computers current ATA(IDE/EIDE) connections. ATA was originally designed for hard drives only, but with help of ATAPI it is possible to connect other devices to the ATA(IDE/EIDE) connections.



ATSC
The Advanced Television Systems Committee, Inc., is an international, non-profit organization developing voluntary standards for digital television. Specifically, ATSC is working to coordinate television standards among different communications media focusing on digital television, interactive systems, and broadband multimedia communications. ATSC Digital TV Standards include digital high definition television (HDTV), standard definition television (SDTV), data broadcasting, multichannel surround-sound audio, and satellite direct-to-home broadcasting.
http://www.atsc.org/aboutatsc.html



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.



Author
To format video into a form ready to burn onto a recordable disc or to stream onto the Internet. VCD, SVCD and DVD Author is to format video into its standard file structure and also add optional menus, chapters, audio tracks, subtitles, slideshows and much more.

VCD File structure
SVCD File structure
DVD File structure

VCD Authoring guides
SVCD Authoring guides
DVD Authoring guides



AVI
Audio Video Interleaved - A multimedia file format for storing sound and moving pictures in RIFF format 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. Microsoft AVI information - MS Sample File

B
B Frame
One of three picture types used in MPEG video. B pictures are bidirectionally predicted, based on both previous and following pictures. B pictures usually use the least number of bits. B pictures do not propagate coding errors since they are not used as a reference by other pictures.



Baldrick
Belt worn over the right shoulder to support a sword or bugle by the left hip.



Bidirectional prediction
A form of compression in which the codec uses information not only from frames that have already been decompressed, but also from frames yet to come. The codec looks in two directions: ahead as well as back. This helps avoid large spikes in data rate caused by scene changes or fast movement, improving image quality.



BIN/CUE
The .BIN / .CUE CD image format was made popular by the CDRWin software. Afterwards many programs have started supporting or partially supporting it, including: Nero, BlindWrite, CloneCD, FireBurner, vcdimager and cdrdao. The .CUE file contains VCD or SVCD or other data track layout information, while the .BIN file holds the actual data. VCDhelp.com bin/cue pages - afterdawn.com



Bitrate
Bitrate or Bit Rate 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).



BitSetting
For a DVD player or drive to identify what kind of disc is loaded, it queries the so called "Book Type Field" found in the lead-in section of each DVD disc. These few bits, commonly referred to as "compatibility bitsettings" tell the drive which low-level format specification does the media conform to, such as DVD-ROM, DVD+R or DVD+RW.
Most DVD players will read a DVD+RW or DVD+R disc without any problems, however a small minority of them report a disc error when a disc is loaded that is not marked as a "DVD-ROM" disc in the compatibility bits. Ususally, these players are physically able to read the disc (since DVD+RW reflectivity is identical to that of a dual layered DVD-Video disc, which all players must be capable of reading), but their compatibility problems are due to different interpretations of these bits in the various firmware versions. In most cases, the problem can be solved by updating the firmware. www.dvdplusrw.org/Article.asp?mid=0&sid=2&aid=42



Block
The block is a matrix of 8x8 elements. They can be 8x8 adjacent luminance or chrominance samples, or the corresponding DCT coefficients.
At the block layer is performed the Discrete Cosine Transform.
Video decoding process at the block layer
Variable length decoding.
The bitstream codewords of the block are decoded to form a vector of quantised DCT coefficient.
Inverse scan.
The vector elements are put into a two-dimensional array, which is the block, following one of two possible patterns. The pattern is defined by the flag alternate_scan which is set at the picture layer. The scanning purpose is to optimize the entropy coding.
Inverse quantisation.
DCT coefficients are converted to their original range of values. See also dct quantisation.
Inverse DCT.
Eventually the IDCT is performed. Now the block elements represent either the image sample (Intra block) or the prediction-error (Non-Intra block).



Blue Screen
See Chroma Key



BookType
See BitSetting.



Bootleg
Produce, distribute, or sell without permission or illegally. Dictionary.com.



bps
Bits per second. A unit of data rate





C
Cable Modem
A device that enables a broadband connection to the Internet by using cable television infrastructure. Access speeds vary greatly, with a maximum throughput of 10 megabits per second (Mbps).



CAM
This type of video was recorded by someone in a cinema with a camcorder and the audience can sometimes be heard or seen! The picture quality is usually OK but the sound is usually very bad and it is hard to make out speech.



Caption
A textual representation of the audio information in a video program. Captions are usually intended for the hearing impaired, and therefore include additional text to identify the person speaking, offscreen sounds, and so on.



Capture
Also called Cap or Capping - To capture video or TV/Sattelite signals to disk. This can include firewire capture from DV cameras. VCDhelp Capture Section



CAV
Constant Angular Velocity, the disc(CD/DVD) is read/written at a constantly increasing speed.



CBR
Constant Bit Rate - the bitrate is the same at any part of a single video or audio stream. VCD standard MPEG video and audio are constant bit rate as are most MP3 standalone audio files. Also see VBR (variable bit rate).



CCE
see Cinema Craft Encoder

http://www.cinemacraft.com/index.htm



CD+G
Compact disc plus graphics. A variation of CD which embeds graphical data in with the audio data, allowing video pictures to be displayed periodically as music is played. Primarily used for karaoke.



CD-DA
Compact disc digital audio. The original music CD format, storing audio information as digital PCM data. Defined by the Red Book standard.



CD-i
Compact disc interactive. An extension of the CD format designed around a set-top computer that connects to a TV to provide interactive home entertainment, including digital audio and video, video games, and software applications. Defined by the Green Book standard. CD-i Assn.



CD-Plus
A type of Enhanced CD format using stamped multisession technology.



CD-ROM XA
CD-ROM extended architecture. A mode 2,multi-session disk where data is on one session and audio/video on another(CD-Extra,Mixed-Mode).



CDA
CD Audio Track - audio files that are on CD media. You can play .cda files only from a CD-ROM. Often the CDA tracks are ripped to WAV or MP3 files.



cdrdao
A program that records / burns audio, video, and data files to CD-Rs/CD-RWs. Cdrdao records CD-Rs in disk-at-once (DAO) mode based on a textual description of the CD contents. The program runs on a variety of operating systems including Linux and Windows (in command line mode or via a GUI). cdrdao homepage



cDVD
See miniDVD



Cell
A 'Cell' is a small segment of a chapter (or part). It is the smallest resolution at which DVD navigation commands can act (e.g. 'Jump to Cell 3 of Part 4 of Title 2'). Typically one chapter contains one Cell but on complex DVDs it may be useful to have multiple Cells per chapter. dvd.sourceforge.net



Chapter
A 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. dvd.sourceforge.net



Chroma bug
The basic "Chroma Bug" manifests itself as streaky or spiky horizontal lines running through the chroma channel, most notably on diagonal edges. As mentioned above, this problem has been around for a long time. It's only just now being noticed largely because one needs a good high-resolution display, such as a front projector and a six foot projection screen, to really see the problem clearly. In addition, the increasingly common use of large progressive displays has really allowed people to get up close to the screen and see every artifact magnified in great detail. Problems that might have gone unnoticed on a 20 inch interlaced TV suddenly hit you in the face. With the advent of relatively high resolution media like DVD, people are starting to compare the video image to the original film image, not to other forms of TV. And suddenly strange problems that people accepted in a TV picture, but would never be allowed on film, look out of place. The Chroma Bug is one of the most visible artifacts around, but because it's specific to MPEG and 4:2:0 encoding, there was nothing written about it until very recently. http://www.hometheaterhifi.com/volume_8 ... -2001.html



Chroma Key
The Chroma Key process is based on the Luminance key. In a luminance key, everything in the image over (or under) a set brightness level is "keyed"out and replaced by either another image, or a color from a color generator. Also known as Blue Screen Compositing, the
Chroma Key Process was made famous by films such as star wars where spacecraft miniatures were composited onto starfield backgrounds.



Chroma noise
Chroma noise affects areas of colour in the image. Instead of being clean, even areas of colour, chroma noise makes colours look grainy due to random noise being inserted into the colour signal. Chroma noise seems to particularly affect blue, although it can potentially be seen in any large expanse of a single colour. Chroma noise is pretty much exclusively an artefact of analogue video processing, and it is very rare to see it in modern, all-digital transfers. Increased MPEG macro-blocking artefacts are a potential side-effect of chroma noise, as the MPEG encoder attempts to encode the extra spurious random noise, leaving less bits for actual picture information.



Cinema Craft Encoder
A very high quality software encoder often refered as CCE .
Though there are different versions of CCE, Cinema Craft SP is the most known and used type http://www.cinemacraft.com/eng/product.html#sp .

Current price on this version is $1995 and can be purchased here :

http://www.cinemacraft.com/eng/purchase.html#sp



Closed GOP
When encoding MPEG video, a Open GOP is one that uses no referenced pictures from the previous GOP at the current GOP boundary. For example the GOP is closed when it starts with an I Frame and subsequent B Frames do not rely on I or P frames from the previous GOP. Also see Open GOP.



CLV
Constant Linear Velocity, the disc(CD/DVD) is read/written at a constant speed.



Coaster
An authored disc that won't play, either due to improper authoring, poor media quality, or write error. The name is derived from the disc's uselessness as a DVD/VCD, may as well be used to set drinks on.



Codec
An acronym for "compression/deccompression", a codec is an algorithm or specialized computer program that encodes or reduces the number of bytes consumed by large files and programs. Files encoded with a specific codec require the same codec for decoding. Some codecs you may encounter in computer video production are Divx, MPEG-1, MPEG-2, Xivd, DV type 1 and type 2 for video and MP3 for audio.



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.



Component Video
A video system containing three separate color component signals, either red/green/blue (RGB) or chroma/color difference (YCbCr, YPbPr, YUV), in analog or digital form. The MPEG-2 encoding system used by DVD is based on color-difference component digital video. Very few televisions have component video inputs.



Composite Video
An analog video signal in which the luma and chroma components are combined (by frequency multiplexing), along with sync and burst. Also called CVBS. Most televisions and VCRs have composite video connectors, which are usually colored yellow.



Compression
The process of removing redundancies in digital data to reduce the amount that must be stored or transmitted. Lossless compression removes only enough redundancy so that the original data can be recreated exactly as it was. Lossy compression sacrifices additional data to achieve greater compression.



Convert
To change from one form into another. In video obviously it is to change one form of video into another. For example, many people like to convert divx to MPEG, quicktime to AVI, etc. Conversions to a final format is called encoding - an example is AVI to VCD MPEG-1. VCDhelp Convert Section



Coring
For noise reduction:
Coring is used to remove fine detail information that does not contribute significantly to the detail of the picture but which adds noise to the image. Imagine the detail information viewed on a scope. About the baseline you'd see primarily the noise information, with the detail extending beyond that. Now imagine that you sliced (or cored) this signal so that only the information above the noise on the baseline came through. You would be left with most of the detail information intact but with much of the noise information removed. The coring adjustment determines how far from the baseline the detail information removed. You want to use just enough coring to reduce the noise in the picture but not so much that the fine detail in the image is affected.


For black level proccessing:
http://neuron2.net/coring.html
Coring is the process where pixels are evaluated against a threshold value and set to pure black if below. This is a "poor man's" noise reduction in the black areas of an image and is implemented in many digital video cameras and capture chips (like the BT848 family).



Crop
To cut away pieces of a video stream without rendering; similiar to cutting a picture with scissors.



CSS
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.



CUE
See BIN/CUE



CVD
China Video Disk - a precursor to SVCD marketed since 1998. Resolutions are 352x480 NTSC, 352x576 PAL, 44.1khz audio (unlike 1/2 D1 DVD that is the same resolution at 48khz audio). Not all players will play CVD (compatible players). CVD Guide

D
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.
http://www.homecinemachoice.com/article ... lVHS.shtml



D1
A video resolution standard. In the NTSC system, "Full D1" means 720x480 pixels, and in the PAL and SECAM systems full D1 is 720x576. You also see "cropped D1", which is 704xNN, which is useful because the 8 pixels on either edge of the video frame aren't supposed to contain useful information. Therefore, some programs will prefer the cropped D1 resolution to save bandwidth. Other popular resolutions are often described in terms of D1: the SVCD resolution is 2/3 D1 (480xNN) and 352xNN is 1/2 D1. Occasionally you see SIF somewhat inaccurately described as 1/4 D1. videographica



DCT
The Discrete Cosine Transform is performed at the Block layer.
For MPEG-2 (ISO/IEC 13818-2), it's specified in the Annex A to the Recommendation.
The input of the DCT and the output of the inverse transform (IDCT) are 8x8 matrices of 9 bits/element, while the DCT coefficients are represented in 12 bits (-2048:+2047).
DCT is used to remove the spatial correlation existing among adjacent pixels in order to allow a more efficient entropy coding.
As DCT is performed to the 8x8 block, only the correlation inside the block can be removed. Besides, the subdivision of the image in 8x8 blocks for the DCT process is the cause of the typical block artifacts of all the DCT based compression algorithms.
If DCT and IDCT processes were performed with infinite precisions, they would be lossless; unfortunatly they are performed with limited integer precision so that, even without quantisation, they can produce some impairment.
The DCT coefficients have a relationship with spatial frequencies and, given that the different components have different subjective importance, DCT gives an important tool to remove also the subjective redundancy.
The first coefficient (0,0) is related to DC component, the coefficients of the first line are related to purely horizontal spatial frequencies, while those of the first column to purely vertical ones, the other coefficients are related to diagonal components.
A representation of DCT coefficients
The image on the left side is the original one, it has been divided in blocks of 8x8 elements for the DCT; the image on the right consists of 8x8 images, each of them represents a coefficient of the DCT and consists of the values that such coefficient takes in all the blocks the DCT has been performed to.
The relevance of the DC values and of the low frequencies values can be noted.

As MPEG-1 and MPEG-2 adopt hybrid DCT compression algorithm, DCT may be applied not only to sample-values (Intra blocks), but also to prediction error values (Non-Intra blocks). For the latter the DC coeffients are no more so important as for the former, but their relevance is quite similar to the other low frequencies coefficients'.



Deinterlace
The process of creating a single frame from the 2 interlaced fields of a video frame. Deinterlacing is used to remove the interlacing artifacts if a still frame is required, or if the video is being used at a different rate than it was created. Extensive Info



Demultiplex
Splitting the video and audio to separate files. Also called "Demux".



Digital8
Camcorder format which allows you to record digital-quality video onto standard Hi8 or 8mm tape. Most Digital8 camcorders also play back analog Hi8 and 8mm recordings, although they do not record in Hi8 or 8mm. A 120-minute Hi8/8mm tape yields one hour of recording when used with a Digital8 camcorder, giving you essentially the same stunning picture quality as you get with Mini DV (500 lines of horizontal resolution).



DiVA
DiVA is a powerful MPEG-1/MPEG-2 video converter for Mac OS X 10.2 or later. It uses QuickTime, MPEG, MOV, SMP, AltiVec, YUV, Cocoa, Quartz, XML and other amazingly great acronyms and buzzwords. It's also fast, high quality, and integrates extremely well with 3ivx D4 4.5, allowing it to perform automated 2-pass encoding with 3ivx

http://diva.3ivx.com/



DivX
DivX™ is a new format for digital video, much like MP3 is a format for digital music. DivX™ is the brand name of a patent-pending video compression technology created by DivXNetworks, Inc., (also known as Project Mayo). 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. DivX.com.



Dolby Digital
Dolby's best-known digital system, is used to provide multichannel surround sound in cinemas from 35 mm film, and in the home from laser discs, DVDs, and digital broadcast television, cable, and satellite systems. It enables the transmission and storage of up to five full-range audio channels, plus a low-frequency effects channel (LFE), in less space than is required for just one linear PCM-coded channel on a compact disc. Dolby.



DROP FRAME
Colour video was slowly introduced into broadcast. It was therefore necessary to make it compatible with black and white receivers and to design colour receivers or televisions to be able to receive black and white programming as well. In order to accommodate the extra information needed for colour the b&w’s 30 frame/second rate was slowed to 29.97 f/s for colour. Although usually not an issue for non broadcast applications, in broadcast, the small difference between real time (or the wall clock) and the time registered on the video can be problematic. Over a period of 1 hour (SMPTE) the video will be 3.6 seconds or 108 extra frames longer in relation to the wall clock. To overcome this discrepancy drop frame is used.



Drop frame: Every frame :00 & :01 are dropped for each minute change (60 X 2 = 120) except for minutes with 0’s (00:, 10:, 20:, 30:, 40: & 50:) (6 X 2 = 12, 120 - 12 = 108)



DSDL
Double Sided Dual Layer DVD. See DVD-18.



DSI
Data Search Information. Information for Fast Forward/Fast Backward and seamless playback. This is real time control data spread throughout the DVD-Video data stream. Along with PGCI, these packets are part of the 1.00 mbit/sec overhead in video applications (Book B). These packets contain navigation information which makes it possible to search and maintain seamless playback of the Video Object Unit (VOBU). The most important field in this packet is the sector address where the first reference frame of the video object begins. Advanced angle change and presentation timing are included to assist seamless playback.



DSL
Digital Subscriber Line - a telephone communication line that uses modulation technology to maximize the amount of data that can be sent over copper wires. DSL is used for broadband and voice connections from telephone switching stations to a subscriber with bitrates similar or slightly less than Cable Modem and greater speeds than ISDN.



DSSL
Double Sided Single Layer DVD. See DVD-10.



DTS
Digital Theater Systems Digital Sound. A product of DTS, Inc., DTS is a multichannel audio compression format similar to Dolby Digital 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. DTS Website



DTV
Digital TV, the standard for broadcasting picture and sound using digital signals, DTV allows for improvements in both picture and sound quality versus conventional Analog TV.
In USA can DTV be delivered in two basic formats: Standard analog Definition (SDTV) or High Definition (HDTV).
In Europe is DTV deliverd in DVB-formats.
USA DTV information.



DV
Digital Video - video captured to a PC from a digital camcorder, often through Firewire. There are two methods of storing DV video data, referred to in this article as type-1 and type-2. Both are stored usually in AVI files. You should be aware of two salient points regarding these respective types to keep in mind when designing multimedia devices and their respective software drivers and utilities:

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.
It is important to understand the format used to store video and audio in an AVI file for VfW.

Although an AVI file can have n number of streams, the most common case is one video stream and one audio stream. The stream format headers define the format (including compression) of each stream. The existence of one video stream, one audio stream, or both in an AVI file is a de facto standard for VfW.

A native DV stream, on the other hand, interleaves the video and audio data into a single stream. As stated in the introduction, Microsoft is defining two methods (type-1 and type-2) that developers can use for storing DV data in AVI files. The method chosen by a developer will impact the ease with which the data can then be used with current and future video editing applications.

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.

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. MS Info
Free Type 1 to Type 2 Converter from Ulead



DV Converter
A device that can capture analog video like VHS, S-VHS, Hi8 and 8mm and convert it to DV. View our Capture Card list for DV Converters.



DV Timecode
Also known as DV Time, a DV or MiniDV camcorder starts recording at 00:00:00. The timecode is drop frame for NTSC (minute differences in timing are made to get the film from 30 fps to 29.97 fps). DV Time is carried on the FireWire cable with the video, audio and Device Control. The biggest problem that arises with DV Time is that it resets to zero if the camera operator does not 'hook' to the end of the previously shot footage (there is an unrecorded gap between recordings).

If dealing with a miniDV or DVCAM tape with 'broken' timecode (that is in many parts), either do a clone copy to another DV tape so that the timecode is created continuously for the entire tape, or name each timecode section as a different tape.



DVB
DVB is an acronym for "Digital Video Broadcasting". DVB was set up by the EBU (European Broadcast Union) to set the standards for digital video transmission. They have published these via ETSI (European Telecommunications Standards Institute) who also set standards for devices such as GSM telephones. In fact there are several DVB standards for different transmission media.Some of these are:
DVB-S Satellite
DVB-C Cable
DVB-T Terrestrial
DVB-SI Specification for Service Information
DVB-CI Common Interface for conditional access
http://www.drakesvision.com/digi3.htm



DVD
DVD once stood for digital video disc or digital versatile disc, but now it just stands for DVD -- the next generation of optical disc storage technology. DVD is essentially a bigger, faster CD that can hold cinema-like video, better-than-CD audio, and computer data. DVD Demystified FAQ.



DVD Changer
A DVD Player that can store 2 or more DVDs (DVD-Video, DVD-Audio) or CDs (CD Audio, VCD, SVCD...) and play them after each other.



DVD Studio Pro
DVD Studio Pro is a software application from Apple that makes it affordable and simple for non-specialists to encode, author, and write professional-quality DVD-Video discs on their Power Mac G4 desktops. If you're shooting and editing using digital video, you can now retain digital quality and precision all the way to the final product. DVD Studio Pro is in a class by itself because it is the only full-featured DVD authoring tool that is both affordable and easy to use.



DVD Video Filesystem
A new file system was chosen for DVD video which would suit both read-only and writable versions. This file system is a subset of UDF 1.02 called micro UDF (M-UDF). The main characteristics of UDF are:

- Robust file exchange
- System & vendor independent
- Writable & read-only media
- Based on ISO 13346

DVD-Video discs use only UDF (not ISO 9660) with all required data specified by UDF and ISO 13346 to allow playing in computer systems. The DVD-Video files must be no larger than 1 GB in size and be recorded as a single extent (ie in one continuous sequence). The first directory on the disc must be the VIDEO_TS directory containing all the files. All filenames are 8.3 format. Disctronics - Burnworld





DVD+R
DVD+Recordable defines a standard for recordable DVD drives and media defined by the DVDRW Alliance. Often called "plus R", the format is write once (compared to DVD+RW wich can be erased and rewritten). The single sided discs can hold 4,700,000,000 bytes (4.38 Gigabytes at 1024 bytes to the kilobyte) with double sided discs holding twice as much. There are no dual layer single sided recordable discs. This format competes with the DVD Forum DVD-R specification. DVDRhelp DVDR information



DVD+R DL
DVD+R DL or called DVD+R9 is a Dual Layer writeable DVD+R. The dual layered discs can hold 7.95 GB or around 8 540 000 000 bytes (called DVD-9) and a double sided dual layered disc 15.9 GB or around 17 080 000 000 bytes (called DVD-18).



DVD+R9
See DVD+R DL



DVD+RW
DVD+RW is a ReWriteable media format of the DVD+R standard.



DVD-10
DVD-10 is a double sided single layer DVD which can fit up to 9.4 GB or 8.7 computer GB. Video DVD, DVD-R/W and DVD+R/W supports this format.



DVD-18
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). Video DVD supports this format but DVD-R/W and DVD+R/W does not support this format.



DVD-5
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". DVDRhelp DVD information



DVD-9
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.



DVD-A
Or called DVDA. See DVD-Audio.



DVD-Audio
DVD-Audio or sometimes called DVD-A is a separate format from DVD-Video. It is a format specifically designed to provide the highest possible audio fidelity capable on DVD. DVD-Audio provides for audio in stereo and in multi-channel surround in a wide range of specifications. In addition to audio, a DVD-Audio disk can contain a limited amount of video, which can be used to display text, such as lyrics or notes. DVD-Audio can only be played on DVD Players with DVD-Audio support (most DVD Players do not support this format). DVD-Audio is currently competing with SACD as the new audio defacto standard. DigitalAudioGuide DVD Audio FAQ



DVD-MP3
This type of disc is created when MP3 audio files are burned on a DVDR/W disc. Very few MP3 capable standalone DVD players supports DVD-MP3 because most players verify DVDR/W as DVD-Video only (compatability list).



DVD-R
DVD-Recordable defines a standard for recordable DVD drives and media defined by the DVD Forum. Often called "minus R", the format is write once (compared to DVD-RW wich can be erased and rewritten). The single sided discs can hold 4,700,000,000 bytes (4.38 Gigabytes at 1024 bytes to the kilobyte) with double sided discs holding twice as much. There are no dual layer single sided recordable discs. This format competes with the DVD+R format. DVDRhelp DVDR information



DVD-R DL
DVD-R DL or called DVD-R9 is a Dual Layer writeable DVD-R. The dual layered discs can hold 7.95 GB or around 8 540 000 000 bytes (called DVD-9) and a double sided dual layered disc 15.9 GB or around 17 080 000 000 bytes (called DVD-18).



DVD-RAM
A recordable format supported by the DVD Forum. It has superior recording features but it is not compatible with most DVD-ROM drives or DVD Video players. It works well when set up like a removable hard disk.




DVD-RW
DVD-RW is a ReWriteable media format of the DVD-R standard.



DVD-SVCD
This is SVCD authored video on a DVDR/W. The DVD standard does not support the SVCD resolution but it may work anyway if the audio has been resampled to 48 khz like the DVD-VCD. Read more here about DVD-SVCD discs.



DVD-TV Combo
A DVD Player and a TV in same unit.



DVD-VCD
Basically this is VCD content authored on a DVDR/W. DVD supports the VCD resolution but the audio has to be resampled to 48 khz. Read more here how to make such a disc.



DVD-VHS Combo
A DVD Player and VHS Video Recorder in same unit. DVD-VHS Combo DVD Players.



DVD-Video
DVD-Video is the video element of the DVD format. DVD Demystified DVD-Video Features.



DVD-VR
The format is known as "DVD dash VR" or DVD-VR. Its actually known from the DVD specification as DVD-RTRW for real-time read/write. One thing that makes it different from the "DVD Video" standard which is used by professionally repliacted DVD's is that the indexing for DVD-VR is forward only. This allows the "writing" of the disc image immediately without having to come up with some cludge to try to write a fully index'd DVD Video file. Burnworld DVD-VR Info



DVD±R
A term used to cover both the DVD-R and DVD+R standards in one word.



DVI
DVI stands for (D)igital (V)ideo (I)nterface. DVI is a new form of video interface technology made to maximize the quality of flat panel LCD monitors and high- end video graphics cards. It is a replacement for the P&D Plug & Display standard, and a step up from the digital-only DFP format for older flat panels. DVI is becoming increasingly popular with video card manufacturers, and most cards purchased include both a VGA and a DVI output port.
In addition to being used as the new computer interface, DVI is also coming out as the digital transfer method of choice for HDTV, EDTV, Plasma Display, and other ultra-high-end video displays for TV, movies, and DVDs. Likewise, even a few of the top-end DVD players are now featuring DVI outputs in addition to the high-quality analog Component Video. Don't expect to throw away all your old video cables just yet, but keep an eye out for DVI availability in the future.
http://www.datapro.net/techinfo/dvi_info.html

E
ECC Constraint Length
The number of sectors that are interleaved to combat bursty error characteristics of discs. 16 sectors are interleaved in DVD. Interleaving takes advantage of typical disc defects such as scratch marks by spreading the error over a larger data area, thereby increasing the chance that the error correction codes can conceal the error.



Edge Enhancement
When films are transferred to video in preparation for DVD encoding, they are commonly run through digital processes that attempt to clean up the picture. These processes include noise reduction (DVNR) and image enhancement. Enhancement increases contrast (similar to the effect of the "sharpen" or "unsharp mask" filters in PhotoShop), but can tend to overdo areas of transition between light and dark or different colors, causing a "chiseled" look or a ringing effect like the haloes you see around street lights when driving in the rain. Video noise reduction is a good thing, when done well, since it can remove scratches, spots, and other defects from the original film. Enhancement, which is rarely done well, is a bad thing. The video may look sharper and clearer to the casual observer, but fine tonal details of the original picture are altered and lost.



EDS
Enhanced data services. Additional information in NTSC line such as a time signal.



EIDE
See ATA.



Elementary Stream
The output of an MPEG video encoder is a video elementary stream and the output of an audio encoder is an audio elementary stream. Before being multiplexed video and audio elementary streams are packetized to form the Video PES and the Audio PES.

PES Packet structure
The packet length is variable:

Header
packet start-code prefix (3bytes)
stream identifier (1 byte)
PES packet length (2 bytes)
optional PES HEADER (variable length)
stuffing bytes (FF) (variable length)
PES packet data bytes

The PES packets are the input of Program Stream and Transport Stream.



Encoding
Encoding is the process of changing data from one form into another according to a set of rules specifiec by a codec. The data is usually a file containing audio, video or still image. Often the encoding is done to make a file compatible with specific hardware (such as a DVD Player) or to compress or reduce the space the data occupies.

Common video encoding methods are DivX, MPEG-1, MPEG-2 and MPEG-4. A common audio encoding method is MP3 although many others exist including MPEG1 audio, DTS, and Dolby Digital.



Entropy coding
In entropy coding, also called variable length coding or Huffmann coding, the more likely values are associated to shorter codewords, while less likely values are associated to longer codewords.
Consequently, known the statistics of the event to code, provided that such statistics are representative enough, it is possible to code such event with an average number of bits lower than in fixed length coding.
So a variable number of bits is produced in the time unity, but many applications (transmission usually) need Constant Bit Rate. In this case the decoder needs a buffer, where it stores the received bits at constant bit rate and from which it gets the bits to decode at variable bit rate. The encoder must have a similar buffer for transmission and must take into account the decoder buffer size and buffer fillness so that neither overflow nor underflow occur at the decoder buffer. This is the purpose of Annex C to Specification ISO/IEC 13818-2 entitled Video buffering verifier.
The tool available to control the bit-rate is the changing of the quantiser_scale, but the rate control algorithm isn't specified and it's a responsability of the encoder.



Error Correction
Error Correction on optical media

in short:

ECC = Reed-Solomon Error correction Code , ECC corrects errors on the fly by rewriting the blocks within the same track.

in depth:

Errors are inevitable but by means of robust error correction systems, CD and DVD can have uncorrectable error rates as low as that specified for computers, i.e., 10-12 (one uncorrectable error in one trillion). Audio applications do not require this degree of accuracy.

Sources of error: Include dropouts from the media (oxide wear, fingerprints, scratches), signal degradation (reflection, intersymbol interference, impedance mismatches, RF interference).

Measures of error: The burst length is the maximum number of adjacent erroneous bits that can be fully corrected. The bit-error rate BER is the number of error bits per total bits. Optical disk systems can handle BERs of 1:100000 to 1:10000. The block error rate BLER is the rate of block or frames per second having at least one incorrect bit. The burst error length BEL is the number of consecutive blocks in error.

Methods of correction: Goal is to introduce redundancy to permit validity checking and error detection, error correction code ECC to replace errors with calculated valid data, and error concealment to substitute approximate data for uncorrectable invalid data. Redundancy includes repeating the data, adding single-bit parity bits (to check if odd or even), checksums (e.g., weighted checksums computed modulo 11), and cyclic redundancy check code CRCC.

CRCC uses a parity check word obtained by dividing a k-bit data block by a fixed number (generation polynomial g) and appended to the data block to creat the transmission polynomial v. When the data u is received, it is divided by the same g, and the result subtracted from the original checksum to yield the syndrome c: a zero sydrome indicates no error. Error correction can be accomplished using mathematical manipulation and modulo arithmetic ... Polynomial notation is the standard terminology in the field: e.g., the fixed number 1001011 (MSB leading) is represented as 1x26 + 0x25 + 0x24 + 1x23 + 0x22 + 1x21 + 1x20 or 26 + 23+ 21 + 20. CRCC is typically used as an error pointer and other methods are used for correction.

Error correction techniques employ block codes having row and column parity (CRCC are a subclass of linear block codes), convolutional or recurrent codes (which introduce a delay), and interleaving including cross-interleaving.

Reed-Solomon R-S codes (Irving Reed and Gustave Solomon 1960) employ polynomials derived from Galois fields to encode and decode block data. They are a subclass of q-ary BCH codes which are a subclass of Hamming codes . They are especially effective in correcting burst errors and are widely used in audio, CD, DAT, DVD, direct broadcast satellite, and other apps. Cross-Interleave Reed-Solomon Code CIRC is used in CDs. It includes the use of C2 then C1 encoders (C1 then C2 on decoding). The C1 level of CIRC is meant to correct small, random errors. The C2 level corrects larger errors and burst errors. Interleaving is used between the C2 (28,24) and C1 (32,2 encoders and deinterleaving is needed on decoding. (28, 24) means 28*8 bits are output for the original 24*8 bit input and the final output is 32 8-bit words of which 8 are for "parity" and 24 are actual data. The cross-interleaving stores one C2 word in 28 different blocks spanning a distance of 109 blocks using delay lines etc., crossing the data array in two directions (thus "cross"). With audio CDs, CIRC can correct burst errors up to 3874 consecutive erroneous bits or symbols (2.5 mm track length) and can well conceal 13,282 error bits (8.7 mm) and marginally conceal 15,500 bits. The CD standard requires a block error rate BLER [the number of data blocks that have any bad symbols at the initial C1 error correction stage] of less than 220 per second averaged over 10 seconds (50 would be typical). There are 7350 blocks/sec on a CD (a block or frame, derived from 24x8=192 bits input data, is 32x8=256 bits output to modulator). The resulting CD data rate = 1.4112 Mbps (input data rate, not including parity bits added by CIRC and EFM).so the maximum Redbook BLER of 220/sec (averaged over 10 sec) allows 3% of the blocks to be erroneous. E12 is the rate of single symbol errors at the C2 encoder, which are correctable. E22 expresses the rate of double symbol errors at the C2 encoder--these are the worst but still correctable errors [the first number is always the number of errors and the second number is always the decoder level]. E32 errors are triple bit errors at C2 and are uncorrectable and require interpolation--they should not appear in a new CD and are unacceptable in a CD-ROM. Other measures of error are the E11, E21, E31. The burst error count BST combines E21 & E22 and expresses the number of consecutive C2 block errors that occur in excess of a threshold value such as 7. A new CD might typically have a raw bit error rate of 1E-5 to 1E-6, BLER = 5, E11 = 5, E22 = 0 and E31 = 0 and should never have E32 uncorrectable errors. Digital audio data can be copied with high reliability.

Error concealment includes interpolation (may be low or high order, zero order simply holds the last good value) and muting.

Credits: "Principles of Digital Audio", by Ken C. Pohlmann



Extro
A video clip, often short, used at the end of a disc. Some common extros are "change Disc" clips for multidisk volumes or credits. On a VCD you should ensure the length of the clip is at least 4 second for compliance with the specification.





F
FAQ
Short for Frequently Asked Questions - a good place to search for information before posting on the forums. VCDhelp FAQ



ffmpegX
A swiss amy knife of MAC video conversion. It has numerous presets, plus the ability to customize your settings to create video to your exact specifications. A few examples of the presets include .mov -> VCD, .mov -> SVCD, .mov ->divx.



Field
In an interlaced video a field is 1/2 of a complete picture (Frame) consisting of the even or odd scanlines in the frame. Usually each field is labeled ie. Field A and Field B. When working with interlaced video it is important to note the Field Order (if Field A comes before Field B in the video stream) especially when encoding. If you notice flicker after encoding you will want to change the field order in the encoding template and reencode.



Filter
Filter: To manipulate a video stream to achieve a desired effect. This can include, but is not limited to, re-sizing, noise reduction, de-interlacing, softening, sharpening, and noise reduction. Video filters are available in many commercial editing packages and some free editors including Virtualdub and AVIsynth.



Final Cut Pro
Final Cut Pro 3 is a comprehensive and innovative editing solution with unprecedented flexibility featuring award-winning editing capabilities, precise color correction tools, and built-in compositing and effects. Revolutionary out-of-the-box G4 real-time effects deliver real-time playback without rendering or additional PCI hardware1. The new OfflineRT format yields over 40 minutes of footage per gigabyte, providing a highly efficient editing workflow. Designed for ease of use, with tools that can expertly handle virtually any video format, Final Cut Pro 3 is the complete solution for professional video editing. With a comprehensive set of award winning features that rival expensive proprietary editing systems, it’s no wonder why Final Cut Pro is quickly becoming the digital editing choice for professional editors and filmmakers worldwide.



Firewire
FireWire is a fast peripheral interconnect standard capable of transfer speeds up to 400 Mbs. It works well for multimedia peripherals such as DV (Digital Video) cameras and other high-speed devices like the latest hard disk drives, CD/DVD burners and printers. Apple FireWire information.



Firmware
The firmware of a device is the program code that is permanently stored in the device's memory. It contains all the necessary software routines to make the device fully functional. New updated firmware is sometimes distributed for dvd players, cd/dvd writers and many other computer devices to add features or fix bugs.



FourCC
A four character code that uniquely identifies a video data stream format. A video player will look up the FourCC code then look for the codec associated to the code in order to play the associated video stream. This idea was used in the IFF multimedia format developed by Electronic Arts for the Amiga in the early 1980s. This file format was copied by Apple (who called it AIFF) and Microsoft (RIFF).
Almost Definitive FourCC List



fps
Frames per second. A measure of the rate at which pictures are shown for a motion video image. In NTSC and PAL video, each frame is made up of two interlaced fields.



Frame
Television:
A set of scanlines in video to make a complete picture. If the video is interlaced the frame consists of both of the interlaced fields (half frames). If the video is progressive the the frame is made up of one continuous scan from top to bottom. The number of scanlines vary in a frame depending on the TV system used. PAL50 uses 625 scan lines, NTSC60 (US) 525.

Video Encoding:
A frame is one picture but depending on the encoding scheme it may not be a complete picture (I-Frame) but dependent on frames before or after the current frame (P-Frame, B-Frame).



Frameserve
The process of creating a direct video "link" from one application to another. For example a video editor application to standalone mpeg encoder so you don't need a plugin or create a temporary video file.


G
Garbage In Garbage Out
Garbage In, Garbage Out or sometimes called Crap In, Crap Out is a computer term describing the fact that the output data is only as good as the input data. It means basicly the same as a video term, the output video and audio quality can only be as good as the source video and audio quality.



GIGO
See Garbage In Garbage Out.



GOP: Group Of Pictures
A Group Of Pictures (GOP) consists of all the pictures that follow a GOP header before another GOP header.
The GOP layer allows random access because the first picture after the GOP header is an Intra picture that means that it doesn't need any reference to any other picture.
The GOP layer is optional, i.e. it's not mandatory to put any GOP header in the bitstream.
In the header there is also the timecode of the first picture of the GOP to be displayed.

The decoding process, as the GOP header is immediately followed by an Intra picture, can begin at that point of the bitstream. Anyway it's possible that some B pictures, following such I_picture in the bitstream, have references coming from the previous GOP and can't be correctly decoded.
In this case the GOP is called an Open GOP because some references from the previous GOP exist; if a random access to such a GOP is performed, some B_pictures shouldn't be displayed .
A GOP is called a Closed GOP when either there are no B_pictures immediately following the first I_picture or such B_pictures haven't any references coming from the previous GOP (in this case a GOP header flag must be set).

In the "coding people" language the GOP length is the period (often expressed in frames) by which an Intra frame occurs. It must be noticed that such a value cannot be found in the bitstream and it is unnecessary to the decoding process. Furthermore it isn't specified any fixed period for the Intra frame. As the presence of the Intra frames is quite important for many applications, it is the encoder that has to provide them, while the decoder has only to work with all the valid bitstreams.



GUI
A GUI (usually pronounced GOO-ee) is a Graphical User Interface to a computer. As you read this, you are looking at the GUI or graphical user interface of your particular Web browser. The term came into existence because the first interactive user interfaces to computers were not graphical; they were text-and-keyboard oriented and usually consisted of commands you had to remember and computer responses that were infamously brief. The command interface of the DOS operating system (which you can still get to from your Windows operating system) is an example of the typical user-computer interface before GUIs arrived. An intermediate step in user interfaces between the command line interface and the GUI was the non-graphical menu-based interface, which let you interact by using a mouse rather than by having to type in keyboard commands. http://searchwebservices.techtarget.com/sDefinition/0,,sid26_gci213989,00.html



I
I Frame
An I frame is encoded as a single image, with no reference to any past or future frames. Often video editing programs can only cut MPEG-1 or MPEG-2 encoded video on an I frame since B frames and P frames depend on other frames for encoding information.



I-MPEG
Intraframe MPEG. An unofficial variation of MPEG video encoding that uses only intraframe compression. I-MPEG is used by DV equipment.



i.Link
The Sony term for IEEE1394 or Firewire



ID3
See MP3 ID3 Tag



IDE
See ATA.



iDVD
Apple's easy DVD creator. iDVD allows users an easy interface to create and burn their video, photos, or data to the dvd format. It allows users to create motion menus and chapter points simply by clicking the mouse. iDVD is like the little brother of DVD Studio Pro.


IEEE1394
The standard name for Firewire


Interlace
Each frame of a video picture is scanned twice. Firstly, all the odd lines are broadcast, then all the even lines are broadcast. Each set of odd/even lines is known as a field. Two fields therefore make up a frame. The point of doing this is to reduce flicker, and not increase bandwidth.


Intro
A video clip, often short, used at the start of a disc. Some common intros are THX, DTS, Dolby Digital sound bites with graphics or a countdown like the old movies. On a VCD you should ensure the length of the clip is at least 4 second for compliance with the specification.


Inverse Telecine
Inverse telecine (IVTC) is when a codec takes a 29.97 frames per second interlaced NTSC video that has gone through the telecine process and reconstructs the original 24 frames per second progressive FILM video.


ISO
Besides the standards organization, this in the CD world is a CD image format somewhat similar to a BIN/CUE image fileset, but the one single .ISO file contains both: the data and the CD layout information. These types of images can be burned with several CD burning programs.


ISO 9660
An ISO 9660 file system is a standard CD-ROM file system that allows you to read the same CD-ROM whether you're on a PC, Mac, or other major computer platform. The standard, issued in 1988, was written by an industry group named High Sierra. Almost all computers with CD-ROM drives can read files from an ISO 9660 file system.
There are several specification levels. In Level 1, file names must be in the 8.3 format (no more than eight characters in the name, no more than three characters in the suffix) and in capital letters. Directory names can be no longer than eight characters. There can be no more than eight nested directory levels. Level 2 and 3 specifications allow file names up to 32 characters long.

IVTC
See Inverse Telecine