Advanced audio coder. An audio-encoding standard for MPEG-2 that is not backward-compatible with MPEG-1 audio.
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.
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.
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
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.
Advanced Regional Copy Control Operating Solution. Sony’s copy protection scheme for DVD-Video, designed to prevent 1:1 digital copying (ripping).
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.
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.
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 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.
(Audio Still Video) A still picture on a DVD-Audio disc.
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.
ATA, EIDE, IDE
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.
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.
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.
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.
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.
AVC, H.264, H264
H.264, MPEG-4 Part 10, or AVC, for Advanced Video Coding, is a digital video codec standard which is noted for achieving very high data compression. It was written by the ITU-T Video Coding Experts Group (VCEG) together with the ISO/IEC Moving Picture Experts Group (MPEG) as the product of a collective partnership effort known as the Joint Video Team (JVT). The ITU-T H.264 standard and the ISO/IEC MPEG-4 Part 10 standard (formally, ISO/IEC 14496-10) are technically identical.
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.
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.
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.
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.
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).
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.
BluRay, Blu-Ray, BD
A Blu-ray Disc (BD) is a next-generation optical disc format designed for high-density storage of high-definition video and data.
Produce, distribute, or sell without permission or illegally.
Bits per second. A unit of data rate
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).
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.
Also called Cap or Capping – To capture video or TV/Sattelite signals to disk. This can include firewire capture from DV cameras.
Constant Angular Velocity, the disc(CD/DVD) is read/written at a constantly increasing speed.
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).
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.
Compact disc digital audio. The original music CD format, storing audio information as digital PCM data. Defined by the Red Book standard.
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.
A type of Enhanced CD format using stamped multisession technology.
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).
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.
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.
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.
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.
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.
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.
Constant Linear Velocity, the disc(CD/DVD) is read/written at a constant speed.
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.
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.
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.
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.
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.
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.
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.
To cut away pieces of a video stream without rendering; similiar to cutting a picture with scissors.
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.
DVHS is a digital recording and playback format for High Definition material. It’s based on the existing 1/2″ VHS-sized cassettes.
A video resolution standard. In the NTSC system, “Full D1” means 720×480 pixels, and in the PAL and SECAM systems full D1 is 720×576. 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.
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.
Demultiplex, Demultiplexing, Demux, Demuxing
Splitting the video and audio to separate files. Also called “Demux”.
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).
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. .
Dolby Digital, AC3, AC-3
Dolby Digital, or AC-3, is the common version containing up to 6 total channels of sound, with 5 channels for normal-range speakers (Right front, Center, Left Front, Right Rear and Left Rear) and one channel for the LFE, or subwoofer. The Dolby Digital format supports Mono and Stereo usages as well.
Double Sided Dual Layer DVD. See DVD-18.
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.
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.
Double Sided Single Layer DVD. See DVD-10.
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.
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 DTV can be delivered in two basic formats: Standard analog Definition (SDTV) or High Definition (HDTV).
In Europe is DTV deliverd in DVB-formats.
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.
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.
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.
A device that can capture analog video like VHS, S-VHS, Hi8 and 8mm and convert it to DV.
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.
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.
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.
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.
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.
DVD+R DL, DVD+R9
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+RW is a ReWriteable media format of the DVD+R standard.
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 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 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”.
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-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).
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-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. This format competes with the DVD+R format.
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).
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 is a ReWriteable media format of the DVD-R standard.
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.
A DVD Player and a TV in same unit.
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.
A DVD Player and VHS Video Recorder in same unit. DVD-VHS Combo DVD Players.
DVD-Video is the video element of the DVD format.
A term used to cover both the DVD-R and DVD+R standards in one word.
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.
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.
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.
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.
Short for Frequently Asked Questions
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.
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: 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.
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.
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.
The first video track that a DVD player will play when a DVD is inserted. Usually a special short video clip, such as Dolby Digital logos, FBI warnings, and company logos. Often accompanied by a PUO.
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).
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.
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.
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).
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.
Garbage In Garbage Out, GIGO
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 basically the same as a video term, the output video and audio quality can only be as good as the source video and audio quality.
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.
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.
An MPEG-2 video encoding mode in which half the horizontal resolution is sampled (352×480 for NTSC, 352×576 for PAL). See also D1
HD-DVD, HDDVD, HD DVD
HD DVD (High Density DVD or High Definition DVD) is a next-generation optical disc format designed for high-density storage of high-definition video and data.
HDMI (High-Definition Multimedia Interface) is the first industry-supported, uncompressed, all-digital audio/video interface. HDMI provides an interface between any audio/video source, such as a set-top box, DVD player, and A/V receiver and an audio and/or video monitor, such as a digital television (DTV).
HDMI supports standard, enhanced, or high-definition video, plus multi-channel digital audio on a single cable. It transmits all ATSC HDTV standards and supports 8-channel digital audio, with bandwidth to spare to accommodate future enhancements and requirements.
High Definition TV is high-resolution digital television combined with Dolby Digital surround sound (AC-3). HDTV is the highest DTV resolution in the new set of standards. This combination creates a stunning image with stunning sound. HDTV requires new production and transmission equipment at the HDTV stations, as well as new television equipment for reception by the consumer. The higher resolution picture is the main selling point for HDTV. Imagine 720 or 1080 lines of resolution compared to the 525 lines people are used to in the United States (or the 625 lines in Europe) — it’s a huge difference!
Of the 18 DTV formats, six are HDTV formats, five of which are based on progressive scanning and one on interlaced scanning. Of the remaining formats, eight are SDTV (four wide-screen formats with 16:9 aspect ratios, and four conventional formats with 4:3 aspect ratios), and the remaining four are video graphics array (VGA) formats. Stations are free to choose which formats to broadcast.
The formats used in HDTV are:
720p – 1280×720 pixels progressive
1080i – 1920×1080 pixels interlaced
1080p – 1920×1080 pixels progressive
High Definition Video (HDV) is a video format designed to record compressed HDTV video on standard DV media (DV or MiniDV cassette tape).
Analog camcorder format which allows you to record video with 400 lines of resolution onto Hi8 tape, or 240 lines of resolution onto standard 8mm tape. Hi8 tapes can get up to 2hours in SP and 4hours in LP modes. Most Hi8 tapes will work in Digital8 camcorders but typically only can record 1 hour of Digital video.
Home Theater Personal Computer, a computer designed to be used as a media center for digital home entertainment such as Movies, Music, Television, Games.
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.
Intraframe MPEG. An unofficial variation of MPEG video encoding that uses only intraframe compression. I-MPEG is used by DV equipment.
The Sony term for IEEE1394 or Firewire
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.
The standard name for Firewire
IMG is an image/iso of a DVD, CD, Floppy. Burn it to a DVD or CD with DVD Decrypter or extract the content with Isobuster or mount it as a virtual DVD/CD unit with Daemon Tools.
Interlace, Interlaced, Interlacing, non-progressive
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.
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, IVTC
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.
Besides the standards organization, this is a CD/DVD image format somewhat similar to a BIN/CUE image fileset, but the one single .ISO file contains both: the data and the CD/DVD layout information. These types of images can be burned with several CD /DVDburning programs.
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.
Kodak Picture CD
Kodak Picture CD is a CD that contains your pictures in JPEG format(.jpg) along with software that lets you view, enhance, share, and print your pictures from your computer. Some standalone DVD Players supports this format also, but then only for viewing. This format will also work on DVD Players that supports “JPEG file viewing” but you may lose some Kodak Picture CD specific features. Kodak Picture CD.
The process or form of video where black horizontal mattes are added to the top and bottom of the display area in order to create a frame in which to display video using an aspect ratio different than that of the display. The letterbox method preserves the entire video picture, as opposed to pan & scan. DVD-Video players can automatically letterbox a widescreen picture for display on a standard 4:3 TV.
Linear PCM, LPCM
Linear PCM (LPCM) is an uncompressed audio format that is similar to CD audio, but with higher sampling frequencies and quantisations. LPCM offers up to 8 channels of 48kHz or 96kHz sampling frequency and 16, 20 or 24 bits per sample but not all at the same time. These values compare with 44.1kHz and 16 bits as used for CD audio. The maximum bit rate is 6.144 Mb/s, which is much higher than Dolby Digital or MPEG-2 coding. LPCM offers high quality (similar to DVD-Audio) but its high data rate leaves little bandwidth for video on a DVD video disc
Compression techniques that allow the original data to be recreated without loss. Contrast with lossy compression.
In the DVD+RW Video format, video can be encoded with a variable bit-rate (VBR). Because the writing process takes place at a constant bit rate, the writing process needs to be suspended and continued frequently. Normally, this would result in a linking loss, making the disc incompatible with read-only devices like DVD Video players and DVD-ROM drives. With DVD+RW it is possible to perform lossless linking, i.e. to suspend and continue the writing process without linking loss. This feature makes the format very efficient and suitable for random write in data as well as video applications.
Compression techniques that achieve very high compression ratios by permanently removing data while preserving as much significant information as possible. Lossy compression includes perceptual coding techniques that attempt to limit the data loss to that which is least likely to be noticed by human perception.
An .m3u file is a special type of metafile playlist that is used with MP3 files that have an .mp3 file extension. The .m3u file includes information about the location of the .m3u file on the computer and the properties of the file. An .m3u file is similar to the ASX playlist files.
If an error message occurs on play then the MP3 files may have been moved or deleted.
A MAC program used to convert .ac3 files to .aiff or .mp3 files.
An analog video copy protection scheme that alters the unseen part of a video signal such that a VCR or other macrovision enabled device may not record the video signal properly. There are several types:
– Automatic Gain Control
– 2-line color stripe
– 4-line color stripe
Symptoms of this include picture fading in and out or color banding of the signal.
A VCD player available for the Mac OS X platform
Main Concept Encoder
A very good mid range (in cost) mpeg encoder. Often found as the encoding engine in other products (Sony Vegas and Adobe Premiere are some such applications that use Main Concept).
Main Concept also makes other video applications such as a compositing program and soon to be released full featured video editing program and low end video editor.
Main Concept also has a very high quality DV codec
The MICROMV cassette is the smallest type of camcorder tape to date — nearly 70% smaller than already tiny Mini DV tapes — so it’s no surprise that all MICROMV camcorders feature an incredibly compact form factor. MICROMV cassettes feature a built-in memory chip for conveniences like custom title storage and index thumbnails for easy access to specific scenes.
Mini DV is a video cassette designed for use in MiniDV digital camcorders. The picture quality of digital video (DV) recorded on a Mini DV cassette is basically identical or better to the quality of DV recorded on a Hi8 or 8mm cassette by a Digital8 camcorder. Mini DV can have up to 530 lines of video resolution for some camcorder models. However, Mini DV tapes are smaller which allows for smaller camcorders. Mini DV 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).
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 650 MB CD-R(W). Not many DVD players will play miniDVD – see the DVD Players miniDVD list for compatible players.
Moving JPEG. A moving image which is made by storing each frame of a moving picture sequence in JPEG compression, then decompressing and displaying each frame at rapid speed to show the moving picture.M-JPEG does not use interframe coding as MPEG does. Sometimes called Motion JPEG.
QuickTime Content (.mov, .qt) – a file format developed by Apple Computer to create, edit, publish, and view multimedia files. QuickTime supports video, animation, graphics, 3D and virtual reality (VR).
MP3 is an acronym for MPEG-1 (or MPEG-2) Layer 3 audio encoding (it is not an acronym for MPEG3). MP3 is a popular compression format used for audio files on computers and portable devices.
The compression in MP3 works on the basis of a “psychoacoustic model” which means that parts of the audio that human ears cannot detect are discarded by the encoder. Although this is a LOSSY process, it can yield very high quality audio files are relatively high compression rates.
A typical MP3 file encoded at 128 kbit/s (12:1 compression) is near CD quality.
MP3 audio is increasingly being used in video production coupled with various MPEG-4 video codecs like divx. The audio may be encoded with a constant or variable bitrate.
MP3 ID3 Tag, ID3
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 picture(s).
MP4 is a new container format, a container format allows you to combine different multimedia streams into one single file. Multimedia containers are for example the well known AVI, MPEG , Matroska, OGM.
MP4 is the global file extension for the official container format defined in the MPEG-4 standard. MP4 is streamable and supports all kinds of multimedia content, multiple audio-, video-, subtitlestreams, pictures, variable-framerates, -bitrates, -samplerates…) and advanced content like 2D and 3D animated graphics, user interactivity, DVD-like menus.
MPA, MP1, MP2
Shorthand for MPEG Audio elemantary stream(no video). Also called MP2 for MPEG Audio Layer2 but MP2 could also be MPEG2 Audio.
MPEG Audio is a family of generic standards for low bit-rate coding
low complexity, good for consumer recording
high efficiency with medium complexity, good for professional recording and for broadcast
high complexity and high efficiency, suitable for very low bit-rates application
An ISO/IEC (International Organization for Standardization/ International Electrotechnical Commission) standard for medium quality and medium bitrate video and audio compression. It allows video to be compressed by the ratios in the range of 50:1 to 100:1, depending on image sequence type and desired quality. The encoded data rate is targeted at 1.5Mb/s – this was a reasonable transfer rate of a double-speed CD-ROM player (including audio and video). VHS-quality playback is expected from this level of compression. The Motion Picture Expert Group (MPEG) also established the MPEG-2 standard for high-quality video playback at a higher data rates. MPEG-1 is used in encoding video for VCD.
An encoding standard designed as an extension of the MPEG-1 international standard for digital compression of audio and video signals. MPEG-1 was designed to code progressively scanned video at bit rates up to about 1.5 Mbit/s for applications such as CD-i. MPEG-2 is directed at broadcast formats at higher data rates; it provides increased support for efficiently coding interlaced video, supports a wide range of bit rates and provides for multichannel surround sound coding such as PCM, Dolby Digital, DTS and MPEG audio.
A proposed variant of the MPEG video and audio compression algorithm and file format. MPEG-3 was intended as an extension of MPEG-2 to cater for HDTV but was eventually merged into MPEG-2.
MPEG-3 should not be confused with MP3 which is MPEG-1 layer 3 popularly used for audio encoding.
An ISO/IEC standard 14496 developed by the Moving Picture Experts Group (MPEG), the committee that also developed MPEG-1 and MPEG-2. These standards made interactive video on CD-ROM, DVD and Digital Television possible. MPEG-4 is the result of another international effort involving hundreds of researchers and engineers from all over the world. MPEG-4 was finalized in October 1998 and became an International Standard in 1999. The fully backward compatible extensions under the title of MPEG-4 Version 2 were frozen at the end of 1999, to acquire the formal International Standard Status early in 2000. Several extensions were added since and work on some specific work-items is still in progress.
MPEG-4 builds on the proven success of three fields:
Interactive graphics applications (synthetic content)
Interactive multimedia (World Wide Web, distribution of and access to content)
MPEG-7 is an ISO/IEC standard developed by the Moving Picture Experts Group. MPEG-7, formally named “Multimedia Content Description Interface”, is a standard for describing the multimedia content data that supports some degree of interpretation of the information’s meaning, Unlike previous MPEG standards aimed at encoding, MPEG-7 is not aimed at any one application in particular; rather, the elements that MPEG-7 standardizes support as broad a range of applications as possible.
A Mac tool used to give the user various helpful pieces of information about a mpeg file.
A compact program for Windows PCs that will give you all the parameters for a MPEG file.
MPV, M1V, M2V
MPEG-1 or MPEG-2 video elemantary stream(no audio). Also called M1V for MPEG-1 video and M2V for MPEG-2 video.
A scene recorded from different viewpoints. Each angle is equal in time length and an Angle Block may contain up to nine (9) angles.
Multiplex, Multiplexing, Mux, Muxing
Joining video and audio to one file. Also called “Mux”.
Describes a video component that can handle 2 or more types of broadcast video standards. Multisystem televisions, videocassette recorders, and DVD players are not found in all stores but are manufactired by many of the large electronics companies. Why buy multisystem? People who move between countries can play/watch video in both countries. Or if you have a relative in India and want to watch the latest from Bollywood in the US then multisystem works also. Multisystem components often cost more than the single system equivalents. Also some DVD players that are billed as single system VCD capable (NTSC / PAL) can play both.
In DVD-Video there are five types of navigation data: Video Manager Information (VMGI), Video Title Set Information (VTSI), Program Chain Information (PGCI), Presentation Control Information (PCI) and Data Search Information (DSI).
A popular PC program for recording data and video CDs and DVDs.
Irrelevant, meaningless, or erroneous information added to a signal by the recording or transmission medium or by an encoding/decoding process. An advantage of digital formats over analog formats is that noise can be completely eliminated (although new noise may be introduced by compression).
Abbreviation of National Television Standards Committee. The NTSC is responsible for setting television and video standards in the United States (in Europe and other parts of the world, the dominant television standards are PAL and SECAM). The NTSC standard for television defines a composite video signal with a refresh rate of 60 fields (half-frames interlaced) per second. Each frame contains 525 lines and can contain 16 million different colors. The resolution of an NTSC VCD is 352×240 pixels, an NTSC SVCD is 480×480, and an NTSC full D1 DVD is 704 or 720 x 480.
Original Equipment Manufacturer. OEMs buy computers or hardware in bulk and customize them for a particular application. They then sell the customized computer under their own name.
Ogg is the name of an open souce multimedia project maintained by the xiph.org foundation. Vorbis refers to the lossy general purpose audio compression format that surpasses mp3 in quality and rivals new formats such as AAC and TwinVQ (a.k.a. VQF).
OGM, Ogg Media file/stream/container is a video and audio container similiar to avi, matroska
When encoding MPEG video, a GOP which uses referenced pictures from the previous GOP at the current GOP boundary. For example the GOP is open when B Frames at the start of a GOP rely on I or P frames from the immediately previous GOP. Also see Closed GOP.
According to the official standards, a cd (and a cd-r disc as well) should have a capacity of 650MB or 700MB of data, or an equivalent of 74 minutes or 80 minutes of audio.
As the laser beam in a cd recorder writes on cd-r media, it travels from the center of the disc towards its edge. Before the physical edge of the cd, there is an already set limit to prevent the laser beam writing beyond that, so that the physical edge of the cd’s writable surface will never be met.
This means that there exists a security zone at the edge of the cd-r media. If we could write into that security zone, we could gain in capacity, since we would be able to write more data on the cd. This is called overburning.
The area at the edges of a television tube that is covered to hide possible video distortion. Overscan typically covers about 4 or 5 percent of the picture.
A P-frame is a video frame encoded relative to the past reference frame. A reference frame is a P- or I-frame. The past reference frame is the closest preceding reference frame.
Partial-Constant Angular Velocity, the disc(CD/DVD) is being read/written at an increasing speed until a certain point (speed). After this point the speed will not increase anymore and remain at this speed.
Short for Phase Alternating Line, the dominant television standard in Europe. The United States uses a different standard, NTSC. PAL delivers 625 lines at 50 fields (half-frames interlaced) per second. The resolution of a PAL VCD is 352×288 pixels, a PAL SVCD is 480×576, and a PAL full D1 DVD is 704 or 720 x 576.
Pan & Scan
The technique of reframing a picture to conform to a different aspect ratio by cropping parts of the picture. DVD-Video players can automatically create a 4:3 pan & scan version from widescreen video by using a horizontal offset encoded with the video, which allows the focus of attention to always be visible.
Playback control, PBC, is available for Video CD (VCD) 2.0 and Super Video CD (SVCD) 1.0 disc formats. PBC allows control of the playback of play items and the possibility of interaction with the user through the remote control or some other input device available.
Pulse Code Modulation. An uncompressed, digitally coded representation of an analog signal. The waveform is sampled at regular intervals and a series of pulses in coded form (usually quantized) are generated to represent the amplitude.
Short for Personal Computer Memory Card International Association, and pronounced as separate letters, PCMCIA is an organization consisting of some 500 companies that has developed a standard for small, credit card-sized devices, called PC Cards. Originally designed for adding memory to portable computers, the PCMCIA standard has been expanded several times and is now suitable for many types of devices.
Not a standard by itself, this term is used when a group of image files are placed on a VCD and displayed in a format like a slideshow. There are two ways of doing this with VCD 2.0 technology:
1) Import the pictures into a video editing program, adding optional music and transition effects as desired. The time between pictures is decided by the filmmaker, not the viewer. The result is output as a VCD or even SVCD motion video file and authored like any motion video to VCD or SVCD. The resolution is limited to VCD 352×240 NTSC, 352×288 PAL or SVCD 480×480 NTSC, 480×576 PAL which may appear grainy or low resolution compaired to the original pictures.
2) Author a photo VCD 2.0 disc encoding each picture as a still MPEG at 704×480 NTSC, 704×576 PAL. This allows better resolution but (probably) lacks transition effects. The resulting collection of still MPEG images can be authored with difficulty in VCDimager/VCDeasy or you can use a program that automates the whole process from images to disc like Ulead DVD Pictureshow 2 (which also does VCD well).
Physical Sector Number
Serial number assigned to physical sectors on a DVD disc. Serial incremented numbers are assigned to sectors from the head sector in the Data Area as 30000h from the start of the Lead In Area to the end of the Lead Out Area.
Picture in picture. A feature of some televisions that shows another channel or video source in a small window superimposed in a corner of the screen.
A microscopic depression in the recording layer of a disc. Pits are usually 1/4 of the laser wavelength so as to cause cancellation of the beam by diffraction.
The smallest picture element of an image (one sample of each color component). A single dot of the array of dots that makes up a picture. Sometimes abbreviated to pel. The resolution of a digital display is typically specified in terms of pixels (width by height) and color depth (the number of bits required to represent each pixel).
Pixel Aspect Ratio
The ratio of width to height of a single pixel. Often means sample pitch aspect ratio (when referring to sampled digital video). Pixel aspect ratio for a given raster can be calculated as y/x multiplied by w/h (where x and y are the raster horizontal pixel count and vertical pixel count, and w and h are the display aspect ratio width and height). Pixel aspect ratios are also confusingly calculated as x/y multiplied by w/h, giving a height-to-width ratio.
Picture outside picture. A feature of some widescreen displays that uses the unused area around a 4:3 picture to show additional pictures.
Portable DVD Player
Versatile portables play anywhere and also connect to your home TV.
A software DVD player for the PC.
The process of preparing data in the final format to create a DVD disc image for mastering. Includes creating DVD control and navigation data, multiplexing data streams together, generating error-correction codes, and performing channel modulation. Often includes the process of encoding video, audio, and subpictures.
An encoding technology developed by Dolby Laboratories, Pro-Logic and Pro-Logic II are methods of encoding 4 channels for Pro-Logic (left, right, center, surround) and 5 channels for Pro-Logic II (left, right, center, left surround, right surround), into a stereo (left, right) channel format to be decoded into 4 or 5 channels with a proper decoder. It is actually just a small amount of inaudible data slipped into a stereo audio stream that can be reconized by a decoder so that the decoder can separate the stereo signal into 4 or 5 channels. A Pro-Logic signal can be encoded into any form of stereo audio stream including digital files such as mpeg-1/2 layer 2, MP3, uncompressed PCM, audio CD’s, and it is also used to get multichannel in VHS tapes and other analog sources. You can listen to Pro-Logic encoded audio streams with any normal equitment but you will only have 2 channels. DVD players are required to have a capable Dolby Digital decoder to downmix a 5.1 Dolby Digital signal on DVDs to a Pro-Logic stereo signal to be output with analog RCA cables. Pro-Logic II can be decoded with Pro-Logic decoders but you will only get 4 channels instead of 5. Pro-Logic is also called Dolby Surround.
The Input of the Program Stream Multiplexer and the Output of the Program Stream Demultiplexer are the Video and Audio Packetized Elementary Streams (PES)
Progressive scan, Progressive, Noninterlaced, Non-Interlaced
Progressive or non-interlaced scanning is any method for displaying, storing or transmitting moving images in which the lines of each frame are drawn in sequence. This is in contrast to the interlacing used in traditional television systems.
In DVD-Video, a menu used to access specific Part of Title (PTT) in a Video Title Set (VTS). Usually referred to as a Chapter Menu.
Film is generally shot and projected at 24 frames per second (fps), so when film frames are converted to NTSC video, the rate must be modified to play at 29.97 fps. During the telecine process, twelve (12) fields are added to each 24 frames of film (12 fields = 6 frames) so the same images that made up 24 frames of film then comprise 30 frames of video.Video plays at a speed of 29.97 fps so the film actually runs at 23.976 fps when transferred to video.
AVID does a 2-3 pulldown (which is used in a lot of film editing) but most other editors use 3-2 pulldown.
2-3 Pulldown vs. 3-2
It is commonly referred to as 3-2 pulldown; while modern telecine machines can go either way. Therefore, AA BB BC CD DD. If the telecine is set for 3-2, you’ll get BB BC CD DD AA.
Another slightly confusing consideration: When the pulldown process occurs, it turns out that the video version of the film runs slightly SLOWER than the original film did. This occurs because the film is running at 24 frames per second, but in order to create the right pattern of A-B-C-D on the video tape, which runs at 29.97 frames per second, the film was actually played at 23.976 fps during the telecine (film->tape process).
Prohibited User Operation. Optional button instructions written into the authored DVD. Often used to disallow buttons from functioning. For example, during the FBI warning on commercial discs, a PUO usually prevents it being skipped by pressing menu or FF buttons.
A digital video software standard developed by Apple Computer for Macintosh (Mac OS) and Windows operating systems.
Quicktime Player can be used to view numerous types of video and audio files.
Redundant Array of Independent Disks – a method used to standardize and categorize fault-tolerant disk systems. RAID levels provide various mixes of performance, reliability, and cost. Three of the the most implemented RAID levels are Level 0 (striping), Level 1 (mirroring), and Level 5 (RAID-5). RAID disk systems may offer advantages during video capture.
Region coding is how Hollywood studios stagger DVD movie releases across the planet. These codes ensure that one country doesn’t get a DVD movie before the same movie is out in that country’s theatres.
All DVD players and discs have region codes. A DVD player and disc must be of the same region or the disc will not play.
If you want to watch movies from other countries, you need a multiregion DVD player. This will allow you to play any disc from any region. However, because TV standards differ, you might need a specialized NTSC/SECAM/PAL TV or a DVD player that can output any signal to the standard your TV accepts.
Region Coding Enhancement, RCE
Abbreviated RCE, it is a digital enhancement added to some studios DVDs to stop region 1 (R1) DVDs from playing on Region-free DVD players.
A database repository for information about a computer’s configuration. The registry contains information that Windows continually references during operation, such as:
– Profiles for each user.
– The programs installed on the computer and the types of documents each can create.
– Property settings for folders and program icons.
– What hardware exists on the system.
– Which ports are being used.
The registry is organized hierarchically as a tree and is made up of keys and their subkeys, hives, and entries.
If programs do not uninstall properly or store configuration information not available via the program interface you might have to manually edit the registry. You can access the registry by running the program RegEdit. WARNING – if you incorrectly modify the registry you can disable programs, file associations or the whole operating system. Making a backup copy of the registry is highly recommended.
The process of converting between different spatial resolutions or different temporal resolutions. This may be based on simple sampling of the source information at higher or lower resolution or may include interpolation to correct for differences in pixel aspect ratios or to adjust for differences in display rates.
1) A measurement of relative detail of a digital display, typically given in pixels of width and height;
2) the ability of an imaging system to make clearly distinguishable or resolvable the details of an image. This includes spatial resolution (the clarity of a single image), temporal resolution (the clarity of a moving image or moving object), and perceived resolution (the apparent resolution of a display from the observer’s point of view). Analog video is often measured as a number of lines of horizontal resolution over the number of scan lines. Digital video is typically measured as a number of horizontal pixels by vertical pixels. Film is typically measured as a number of line pairs per millimeter;
3) the relative detail of any signal, such as an audio or video signal. Also see lines of horizontal resolution.
Video information in the form of red, green, and blue tristimulus values. The combination of three values representing the intensity of each of the three colors can represent the entire range of visible light.
To take off the audio or video from a CD or DVD. Often CD Audio is “ripped” to MP3 files or DVD video ripped to VOB files.
Super Audio CD is the next generation of audio disc, offering full-range, uncompressed digital multi-channel surround sound. SACD can also be backward compatible using so called hybrid discs with an extra layer that allows them to be played on conventional CD players but then only with ordinary CD quality. SACD can be played on SACD Players, DVD Players with SACD support and if using hybrid discs also CD Players. SACD is currently competing with DVD-Audio as the new audio defacto standard.
The number of times a digital sample is taken, measured in samples per second, or Hertz. The more often samples are taken, the better a digital signal can represent the original analog signal. Sampling theory states that the sampling frequency must be more than twice the signal frequency in order to reproduce the signal without aliasing. DVD PCM audio allows sampling rates of 48 and 96 kHz.
Converting analog information into a digital representation by measuring the value of the analog signal at regular intervals, called samples, and encoding these numerical values in digital form. Sampling is often based on specified quantization levels. Sampling may also be used to adjust for differences between different digital systems.
Serial ATA is an evolution of the Parallel ATA storage interface. Serial ATA is a serial link, a single cable with a minimum of four wires creates a point-to-point connection between devices. Transfer rates for Serial ATA begin at 150MBps.
Scalability offers a set of tools by which video can be coded at different Resolutions (different scales) in one total bitstream.
On the decoder side, video can be decoded at the suitable resolution (scale) extracting a portion of the total bitstream.
It adds compatibility and error concealment.
A video usually recorded form a promotional video tape or DVD which is sent to censors and film critics etc. The quality is usually as good as a commercial video or DVD. Sometimes a copyright message appears on the screen.
Small Computer System Interface is a standard electronic interface between your computer and its peripherals(hard drives, CD and DVD Readers and Writers and other peripherals). .
Standard Definition Television or SDTV refers to DIGITAL transmissions with 480-line resolution, either interlaced or progressive scanned formats. SDTV offers significant improvement over today’s conventional NTSC picture resolution, similar to comparing DVD quality to VHS, primarily because the digital transmission eliminates snow and ghosts, common with the current NTSC analog format. However, SDTV does not come close to HDTV in both visual and audio quality.
Séquential Couleur Avec Mémoire/Sequential Color with Memory. A composite color standard similar to PAL (image format 4:3, 625 lines, 50 Hz and 6 Mhz video bandwidth), but currently used only as a transmission standard in France and a few other countries. Video is produced using the 625/50 PAL standard and is then transcoded to SECAM by the player or transmitter.
A sequence consists of all the pictures that follow a sequence header till a sequence_end_code.
Encoding and displaying parameters are transmitted with the sequence header.
The sequence header can be repeated in order to allow random access, but all the data elements of the repeated sequence header, except those concerning quantisation matrices, must have the same values as in the first sequence header.
The repeated sequence header must precede in the bitstream either an I-picture or a P-picture. In the case that random access is performed to a P-picture, it’s possible that the decoded pictures may not be correct.
As the GOP layer is optional the management of the pictures is performed at the sequence layer.
An important item is the fact that the frames are not coded in the order in which they are displayed.
In particular the B_frames, that use references “from the future”, are always coded after the P_frame (or the I_frame) used for backward predictions.
The frame reordering causes a delay in the coding and decoding processes. On the coder side the delay is given by the number of B_frames, that must wait for the following P_frame (or I_frame), while the decoder should wait for having full the two frame-memories before starting the display.
For special application is possible to code the sequence without any B_frame with the mode low_delay, set at the sequence layer. In this case the decoder needs only one frame-memory.
In an MPEG file, a sequence header is placed before one or more groups of pictures (GOPs) and contains encoding and displaying parameters. The sequence header can be repeated in order to allow random access, but all the data elements of the repeated sequence header, except those concerning quantisation matrices, must have the same values as in the first sequence header. The repeated sequence header must precede in the bitstream either an I Frame or a P Frame.
To allow for better access and editing, many people place a sequence header after every GOP. In final output, some place fewer sequence headers in (every 5 GOPs, etc.) to save bitrate or make the file smaller.
Source Interchange Format is a video resolution standard defined as 352×240 for NTSC and 352×288 for PAL and SECAM.
Uses a 1.0 pixel aspect ratio. Use this setting if your video has a 640×480 or 648×486 frame size.
Single Sided Dual Layer DVD. See DVD-9.
Single Sided Single Layer DVD. See DVD-5.
SVCD stands for ‘Super VideoCD’. A SVCD is very similiar to a VCD, it has the capacity to hold about 35-60 minutes on 74/80 min CDs of very good quality full-motion MPEG-2 video along with up to 2 stereo audio tracks 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 drive with the help of a software based decoder / player.
Cinematic film movies are shot at 24 progressive frames per second speed. A Frame is the smallest unit of a 24 fps FILM format. NTSC video is a “field-based” format of 59.94 fields per second. A Field is the smallest unit in interlaced video format. 2 fields make up 1 frame. So, this 59.94 fields per second equals 29.97 frames per second. 1 second in FILM (24 frames) is NOT equal to 1 second in NTSC Video (29.97 frames).
To be able to match the speed of an NTSC Video, conversion from a FILM format to an NTSC Video format undergoes a process called 2:3 pulldown or TELECINE. This process, in simplest terms, means “to add 6 frames so that a 24 fps becomes 30fps which is close to 29.97 fps (another trick is used to get to 29.97).
A video recorded in a cinema but usually on an expensive camera and a seperate audio source or direct audio connection (so the audience cannot be heard). The result is a video generally of very good quality.
Information recorded with audio or video to indicate a position in time. Usually consists of values for hours, minutes, seconds, and frames. Also called SMPTE time code. Some DVD-Video material includes information to allow the player to search to a specific time code position.
A DVD ‘Title’ is generally a logically distinct section of a DVD-Video. For example the main feature film on a DVD might be Title 1, a behind-the-scenes documentary might be Title 2 and a selection of cast interviews might be Title 3. There can be up to 99 Titles on any DVD
1) A distinct element of audiovisual information, such as the picture, a sound track for a specific language, or the like. DVD-Video allows one track of video (with multiple angles), up to 8 tracks of audio, and up to 32 tracks of subpicture;
2) one revolution of the continuous spiral channel of information recorded on a disc.
A relatively short video that is either used to preview a longer feature film, a television program, food, a sound system or other advertizing. Trailers often come before a main feature movie as an intro.
Another name for encoding.
A more technical term would be “The reformatting of content, without changing the source, to another type of content – most often of a different format than the original (but does not have to be)”
The Input of the Transport Stream Multiplexer and the Output of the Transport Stream Demultiplexer are the Video and Audio Packetized Elementary Streams (PES)
MPEG-2 Transport Stream:
may contain one or multiple programs (even with independent time-base); is suitable to no error-free transmision; has a fixed length packet structure.
One of the major achievements of DVD is that it has brought all the conceivable uses of CD for data, video, audio, or a mix of all three, within a single physical file structure called UDF, the Universal Disc Format. Promoted by the Optical Storage Technology Association (OSTA), the UDF file structure ensures that any file can be accessed by any drive, computer or consumer video. It also allows sensible interfacing with standard operating systems as it includes CD standard ISO 9660 compatibility. UDF overcomes the incompatibility problems from which CD suffered, when the standard had to be constantly rewritten each time a new application like multimedia, interactivity, or video emerged.
The version of UDF chosen for DVD-Video to suit both read-only and writable versions – is a subset of the UDF Revision 1.02 specification known as MicroUDF (M-UDF).
Because UDF wasn’t supported by Windows until Microsoft shipped Windows 98, DVD providers were forced to use an interim format called UDF/ISO (UDF Bridge).
UDF has been revised and now appears in revisions 1.02, 1.5, and 2.0.
Also called UDF bridge, UDF/ISO is a hybrid filesystem utilizing UDF and ISO 9660. Developed because UDF wasn’t supported by Windows until Microsoft shipped Windows 98, DVD providers were forced to use an interim format. Windows 95 OSR2 supports UDF Bridge, but earlier versions do not. As a result, to be compatible with Windows 95 versions previous to OSR2, DVD vendors had to provide UDF Bridge support along with their hardware.
DVD-ROM discs use the UDF Bridge format. (Note: Windows 95 was not designed to read UDF but can read ISO 9660). The UDF Bridge specification does not explicitly include the Joliet extensions for ISO 9660, which are needed for long filenames. Windows 98 and later MS operating systems read UDF so these systems have no problem with either UDF or long filenames.
User Operation Prohibitions. Settings that prevent the viewer from skipping or fast-forwarding certain parts of DVDs.
Universal Serial Bus is the solution for all PC users who want an instant, no-hassle way to connect new hardware like digital joysticks, scanners, digital speakers, digital cameras or a PC telephone to their computer. USB makes adding peripheral devices extremely easy. With USB-compliant PCs and peripherals, you just plug them in and turn them on. USB 2.0 (USB2) is the latest USB technology. This technology is approximately forty times faster than the previous USB 1.1 technology, increasing the speed of the device to PC connection from 12Mbps on USB 1.1 to up to 480Mbps on USB 2.0.
Vertical Blanking Interval – the part of a TV transmission that is blanked, or left clear of viewable content, to allow time for the TV’s electron gun to move from the bottom to the top of the screen as it scans images. This blank area is now being used to broadcast closed captioned and text formatted information.
Variable Bit Rate – the bitrate can vary at any part of a single video or audio stream. VBR can is used to increase bitrate during high motion scenes in a video or to reduce overall file size. DVD MPEG-2 video is often variable bit rate. Also see CBR (constant bit rate).
VC-1 is a video codec standard. Its most popular implementation is Windows Media Video 9. It is an evolution of the conventional DCT-based video codec design also found in H.261, H.263, MPEG-1, MPEG-2, and MPEG-4. It is widely characterized as an alternative to the latest ITU-T and MPEG video codec standard known as H.264/MPEG-4 AVC. VC-1 contains coding tools for interlaced video sequences as well as progressive encoding. The main goal of VC-1 development and standardization is to support the compression of interlaced content without first converting it to progressive, making it more attractive to broadcast and video industry professionals.
VCD stands for ‘Video Compact Disc’ and basically it is a CD that contains moving pictures and sound. If you’re familiar with regular audio/music CDs, then you will know what a VCD looks like. A VCD has the capacity to hold up to 74/80 minutes on 650MB/700MB CDs respectively of full-motion video along with quality stereo sound. VCDs use an encoding standard called MPEG-1 to store the video and audio. A VCD can be played on almost all standalone DVD Players and of course on all computers with a DVD-ROM or CD-ROM drive with the help of a software based decoder / player.
Video for Windows (VfW) The first video capture and display system developed by Microsoft for the Windows operating system. The design of VfW video capture was optimized for capturing movies to disk. Features important to video conferencing, TV viewing, capture of video fields, and ancillary data streams are missing from the VfW architecture. To circumvent these limitations, vendors augmented VfW by implementing proprietary extensions. However, without standardized interfaces, applications that use these features must include hardware-dependent code.
VHS an analog format capable of delivering 240 lines of video resolution, along with stereo sound that’s nearly as good as CD (in dynamic range and frequency response). Blank tapes usually feature either 120 minutes or 160 minutes of recording time at the highest recording speed (6 hours or 8 hours at the slowest speed). VHS and VCR’s have been phased out in favor of DVD players and other digital tape media.
The process for changing a video from one format to another by altering the resolution and/or the bitrate. Normally the result of this process is a movie with a different compression. For a proper encoding you need a piece of software and/or hardware, which is called codec.
The UDF file name used for DVD-Video directory on a DVD disc volume. Files under this directory name contain pointers to the sectors on the disc which hold the program streams.
All DVD movies are stored in on a DVD video disc in so-called VOB files. VOB files usually contain multiplexed Dolby Digital audio 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 (all upper case).
All VOB files are essentially MPEG2 Program streams with audio, video, sub-picture and navigation data multiplexed. A VOB file is organized as a set of cells; a cell is a basic unit of play data. Each cell consists of a sequence of units called VOBUs. Each VOBU is a sequence of packs. The first pack in a VOBU is a navigation pack and contains Program Control Information (PCI) packet and Data Search Information (DSI) packet. The remaining packs contain audio, video and sub-picture data multiplexed together. Each pack has a fixed size of 2048 bytes. A pack typically contains only one data packet and may be stuffed with dummy bytes or a packet called ‘padding’ bytes/packet to make it a fixed size.
DVD allows easy navigation in its audio and video data. Information for navigation across different VTS is contained in the VMGM. Within a title, the play order of different cells (from one or more VOBs in the title) is described in a Program Chain (PGC). A PGC is a logical unit to present a part of or the entire Title or Menu. A PGC is further divided into programs. Each program contains integral number of cells. A Title may have one or more PGCs. However, a Title that has parental guidance levels, will have more than one PGC. Depending on the parental level selected by the DVD disk viewer, the PGCs are selected for being played. PGC contains PGCI which gives the order of presentation of cells within that PGC.
The information for presentation of a cell, such as the angle information for seamless and nonseamless play and highlight information is contained in the Navigation packs occurring within the cell.
When playing non-seamlessly, the cells within a logical block are placed contiguously. Therefore, during cell presentation, intermittent blocks may have to be skipped depending on the angle iinformation selected by the DVD disk viewer.
An angle block is a logical block containing cells for different angle presentations. During presentation, not all the cells within the block are played. The different angle cells are of almost the same play time and since they are placed adjacent to each other, the DVD disk viewer can seamlessly change from one angle to another.
When playing a parental level seamlessly, cells from different VOBs may be interleaved in a logical block. Such a block is called an interleaved block. Each unit of VOB that lies in an interleaved block is called an ILVU of that VOB. This means that the cells in a VOB may not be placed contiguously over the physical address space and may be interleaved with ILVUs from other VOBs.
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 itself 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).
A video image wider than the standard 1.33 (4:3) aspect ratio. When referring to DVD or HDTV, widescreen usually indicates a 1.85 (16:9) aspect ratio.
A software DVD player for the PC.
Windows Media Audio.
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.
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).
Windows Media file with Audio and/or Video (WMV): You can use a .wmv file either to download and play files or to stream content. The .wmv file format is similar to the .asf file format.
WMV HD stands for Windows Media Video High-Definition.
eXtended SVCD – XSVCD has same features as SVCD but it is possible to use higher bitrates and higher resolution to get higher video quality. XSVCD is basically everything that uses MPEG-2 video, is not within the SVCD standard or close to DVD, and burned in “SVCD” Mode on a CD-R or CD-R(W). XSVCD 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.
eXtended VCD – XVCD has same features as VCD but it is possible to use higher bitrates and higher resolution to get higher video quality. XVCD is basically everything that uses MPEG-1 video, is not within the VCD standard, and burned in “VCD” Mode on a CD-R or CD-R(W). XVCD can be played on some hardware VCD or DVD players and many computers with appropriate software.
XviD is an ISO MPEG-4 compliant video codec. It’s not a product but an open source project which is developed and maintained by people around the world.
The analog luminance and color-difference components of a color image (in digitized form, as Y, Cr, Cb, in JPEG) or video (NTSC and PAL). If you take the typical Red, Green, Blue colorspace (RGB), you can get YUV from:
Y (or Luma)= 30% Red + 59% Green + 11% Blue Analog Luminance
U (or Cb)=R-Y the red signal component minus the luminance
V (or Cr)=B-Y the blue signal component minus the luminance
The large percentage of Green and the small percentage of Blue (along with Green being sent twice) help to explain why chroma-keying for video is done against greenscreens and not bluescreens like film.
YUV was originally developed for backward compatibility with black-and-white television.
Originally, TV stations only transmitted the black and white signal. When color TV was to be deployed, most people still only owned a black-and-white set. It became clear that transmitting an RGB signal separately from a black-and-white signal would be highly impractical. A system was needed in which a TV station could transmit a signal that could be seen as monochrome on the older but still common black-and-white TV sets, but the same signal should be in color on the new color TV sets. YUV encoding allows the signal had to continue to have the black-and-white image, and the color information is added to it transparently.
Many video filters handle video streams in either RGB or YUV colorspace. Some can handle both.
The human eye is less sensitive to colour variations than to intensity variations. YUV allows the encoding of luminance (Y) information at full bandwidth and chrominance (UV) information at reduced bandwidth.
Often called component video, there are different standards for pro video and consumer video. YUV is used on such video types as Beta SP, a very common pro video editing format.