Glosario de Ripeo, por Doom9

Esta no pretende ser la más comprensible y exacta de las descripciones de los términos más comunes en el Ripeo de DVDs pero te va a ayudar a darte una idea general. No es totalmente exacta y algunos términos están simplificados deliveradamente. Mandame un mail si te parece que algo está mal o si sabés de algún término que se pueda agregar.

Glossary
  • AAC
  • Authentication
  • AC3
  • ASF
  • AVI
  • BUP
  • Cell (ID)
  • Codec
  • Container
  • DAR
  • Deinterlace
  • Demultiplexing (demux)
  • Descrambling
  • Digital Video
  • DivX
  • DIVX
  • DRC
  • Elementary stream (ES)
  • Field
  • FourCC
  • Frame
  • Interlaced
  • I und P Frames
  • Interleaving
  • Inverse Telecine (IVTC)
  • iDCT
  • IFO
  • Keyframe
  • m1v/m2v
  • miniDVD
  • MPEG
  • MPEG4
  • MM4
  • Multipass Encoding
  • Multiplexing (mux)
  • Normalizing
  • OGM
  • PGC
  • Program stream (PS)
  • Progressive
  • Quantizer
  • rff/tff flags
  • Ripping
  • SBC
  • Streamlist
  • SVCD
  • Telecine
  • VBR
  • VCD
  • VKI
  • VM2
  • VOB ID
  • Vob Files
  • VTS
  • Wavelets
  • WindowsMedia
  • XCD
  • XviD
  •  

    AAC

    Advanced Audio Coding will be the successor of AC3 audio. It is based on AC3 while adding a number of improvements in various areas. Currently player and hardware support for this upcoming audio format is still very limited.

    Authentication [autenticación]

    Antes que una película pueda ser reproducida, el reproductor y el disco deben establecer una línea de comunicación segura en la que puedan transferir la película. Antes de que puedan establecer esa línea necesitan asegurarse que del otro lado esté la "persona" correcta" - esto se logra usando algunos intercambios de claves, verificaciones, etc.

    AC3

    Originalmente conocido como "Audio Coding 3" AC3 es un sinónimo para Dolby Digital actualmente. Dolby Digital es una tecnología avanzada de compresión que permite codificar 6 canales separados de audio a tasas de bits de 320kbit/s, o mas. Para mas información checa el sitio de Dolby.

    ASF

    Advanced Streaming Format (Formato Avanzado de Streaming). Es la respuesta de Microsoft a Real Media y el resto de los medios de streaming en general.

    AVI

    Audio Video Interleave (Audio y Video Entrelazados) Es el formato más comunmente usado en PCs con Windows. Define cómo el video y el audio esán atados uno al otro, sin especificar un codec

    .BUP file

    A bup file is a Back UP file of an IFO file. These files are commonly found on DVDs.

    Cell (ID)

    A cell is the smallest video unit on a DVD. Normally used to contain a chapter it can also be used to contain a smaller unit in case of multiangles or seamless branching titles.

    Codec

    COdificador/DECodificador. Un codec es un software que te permite codificar algo - generalmente audio o video - a un formato específico y puede, a su vez, decodificar cosas codificadas que estén en su mismo formato. Codecs Populares: MPEG1, MPEG2, MPEG-4, Indeo, etc. AVI, ASF, etc no son codecs sino formatos que pueden ser codificados usando diferentes codecs.

    Container

    A container is, like the name says, a construct to contain data - in this case video and audio date and possibly subtitles and navigational information. For instance, you would like to put a soundless video stream and the audio track together in one file. To do that you need a container format. Examples of container formats are: AVI, ASF, OGM, Quicktime, VOB and MPG.

    DAR

    DAR siglas de "Display Aspect Ratio" (Radio de relación con el aspecto) y indica las dimensiones de la pantalla. La mayoría de los monitores de PC tienen un DAR de 4:3, esto significa que el tamaño horizontal es 4/3 (1.333) el tamaño vertical. En el caso de los televisores tenemos un montón de viejos TVs con un DAR de 4:3 y algunos pocos TVs con 16:9. Como podrás imaginar la relación 16:9 muestra una imagen mas "panorámica" que la 4:3 teniendo el mismo tamaño de manera diagonal. Las pantallas 16:9 son recomendables para las producciones Americanas que son grabadas con relaciones 1:2.35 (20:9) o 1:1.85 (16.5:9) (significando esto que el tamaño horizontal de la imagen es 2.35 ó 1.85 veces mas grande que el tamaño horizontal).

    Deinterlace

    The process of restoring a progressive video stream out of an interlaced one is called deinterlacing.

    Demultiplexing (Demultiplexando)

    Es lo opuesto a multiplexing [multiplexando]. En este proceso un stream combinado de audio/video es separado en el número de streams que contiene (un stream de video, por lo menos uno de audio y un stream de navegación). Todos los codificadores de VOB demultiplexan los archivos VOB antes de codificar (FlaskMpeg, mpeg2avi, dvd2mpg, ReMpeg2) y cada reproductor de DVD hace lo mismo (audio y video son tratados por diferentes circuitos, o decodificados por diferentes filtors en una pc). 

    Descrambling

    Normalmente los DVDs están CSS scrambled - imagina que decides darla un número a cada letra, empezando con 1 para a, etc. Una oración se convierte en un par de dígitos - eso es lo que llamamos scrambled (que traducido directamente al español sería revuelto). Por supuesto que el CSS es mucho mejor que eso, pero no deja de ser fácil de crackear. Descrambling significa revertir el proceso de scrambling, transformar los dígitos otra vez en la oración, o hacer que la película pueda verse otra vez - podés intentar copiar una película a tu disco rígido cuando hayas autenticado la lectora de DVD y reproducirla, vas a obtener la imagen alterada porque está todavía revuelta. Los descramblers comunes de CSS usan o una lista de claves conocidas (DeCSS o DODSrip - contienen un gran número de claves pero no todas) o tratan de obtener la clave mediante un ataque criptográfico (VobDec - por eso es que funciona en la mayoría de los discos, ya que no depende de un número limitado de claves que pueda haber en una lista).

    Digital Video (Video Digital)

    El video digital normalmente está comprimido ya que si no almacenar una película no comprimida ocuparía espacio en el orden de los Terabytes - miles de Gigabytes o para los matemáticos entre ustedes: 10^12 Bytes). Como la compresión estandar sin pérdida de datos es insuficiente para video, los codecs de video tienen que deshacerse de la información no importante - cosas que el ojo humano no podrá ver o es poco probable que lo haga. Como eso tampoco es suficiente, los algoritmos de compresión modernos usan keyframes (cuadros clave), cuadros I y P para ahorrar espacio.

    DivX

    No confundirlo con el ahora - gracias a Dios - obsoleto systema DIVX (DIgital Video eXpress) introducido por Circuit City '98. Hay dos tipos de DivX actualmente: DivX ;) es el nombre de los codecs Mpeg4 hackeados deMicrosoft (Windows Media Video V3). Esos codecs fueron desarrollados por Microsoft para usar en la arquitectura de Windows Media e inicialmente soportaba la codificación de AVIs y ASFs, pero todas las versiones no-Beta traían blockeada la codificación de AVIs - y sólo unas pocas herramientas soportan ASF actualmente. Lo que hicieron los creadores de DivX fue remover dicho bloqueo haciendo posible codificar AVIs nuevamente, y le cambiaron el nombre a DivX video para prevenir la confusiones, ya que es posible tener tanto la versión sin hackear como la hackeada en la misma computadora si usás el Windows Media Encoder. Las últimas versiones de DivX también incluyen un codec de Windows Media Audio llamado DivX audio - este codec no es de todo bueno aún y su uso se limita a bitrates altos. Este codec también es conocido como DivX3.

    El otro DivX es un codec de video MPEG-4 completamente nuevo desarrollado por DivXNetworks. Ofrece controles de codificación mucho más avanzados y codificación por doble pasada. Además, este codec puede reproducir película del viejo DivX ;) (DivX3). Este codec es comunmente llamado DivX4.

    DIVX

    DIVX era básicamente un DVD sin todas las características especiales - sin extras, baskstages, trailers, multi-idioma, pantalla ancha - introducido por Circuit City y un grupo de codiciosos abogados de Hollywood para controlar completamente la distribuición de películas hasta el usuario final y tener control completo de la reproducción de la película en tu hogar. DIVX era pay-per-view (pagar-para-ver) y un reproductor de DVD tenía que estar "modificado para DIVX" y tenía que ser conectado a una línea de teléfono para comunicarse con la computadora central de DIVX que registraba cuándo veías una película y facturaba en tu tarjeta de crédito. Una película costaba US$4.50 - que incluía un período de 48 hs en el que se podía ver la película - y US$2.50 por períodos adicionales. El DIVX se cerró luego de menos de un año de opeación debido a la poca cantidad de títulos con los que contaba (Warner, Sony, New Line, y el resto de estudios chicos se oponían a lanzar cualquier título en ese formato - MUCHAS GRACIAS!!!) y a la prensa negativa que tuvo, principalmente de sitios de DVD en internet que concluyeron en serias publicaciones impresas y apariciones en las noticias de TV.

    Un DIVX usa triple encriptado DES, que es muy seguro contra ataques criptográficos y a menos que puedas crackear ese encriptado no hay manera de ripear los discos. En otras palabras, tus discos DIVX probalbemente permanezcan inútiles para siempre.

    DRC

    Dynamic Range Compression. AC3 Tracks contain a much larger dynamic range that most audio equipment can handle, therefore most standalone and software DVD player will compress the dynamic range somewhat, according to the actual dynamic range. In layman terms the volume will be augmented dymanically, e.g. explosions won't become louder or only a bit louder, whereas in normal dialogues the volume will be augmented quite a bit. Since your player will do the same this is the way to go to have augmented volume.

    Elementary Stream (ES)

    An elementary stream is a single (video or audio) stream without container. For instance a basic MPEG-2 video stream (.m2v or .mpv) is an MPEG-2 ES, and on the audio side we have AC3, MP2, etc files that are ES. Most DVD authoring program require ES as input.

    Field (Campo)

    Las pistas de vídeo interlaced (entrelazadas) contienen campos en lugar de frames (cuadros).

    FourCC

    FourCC stands for four character code and is a code that uniquely identifies a video data stream format. A movie player will look up the FourCC code then look for the codec associated to the FourCC code in order to play a certain video stream. A few examples: DIV3 = DivX Low-Motion, DIV4 = DivX Fast-Motion, DIVX = DivX4.

    Formats used for DVD conversion Frame

    The basic source of a movie. One frame represents one image. A movie usually runs at 24 frames per seconds, so it has 24 different images per second. Imagine 24 images with a bird on it, in the first image it's on the left, then it gradually movies somewhat to the right. On the 24th frame the bird is on the right end of the image. Imagine these 24 images being played in sequence fast enough and it looks like a bird would fly from left to right to the human eye.

    I and P Frames

    Frame describing only the differences to the frame before (this is less than accurate but I think you'll get the picture that way). Say we have a keyframe with a bird before a cloudy sky. Then we can use I frames which say something like this : move the bird an inch to the left and one inch to the bottom.

    iDCT

    The video information inside MPEG files is stored in the frequency domain rather than in the spatial domain (the images we see). That way, the information gets compacted and that compactation can be used to compress (reduce) the amount of information you have to send over the transmission channel. MPEG uses the DCT (Discrete Cosine Transform) to translate spatial information into frequency information.
    To bring back the spatial information from the MPEG stream you have to apply the iDCT, that is, the Inverse Discrete Cosine Transform, that undoes the DCT that was used during encoding.
    DCT and iDCT are basically the same as DFT (discrete fourier transforms) but the results are integers rather than complex reals you get in i/DFT. For more info please refer to a university-level book about DSP, communication systems or similar.

    IFO file

    InFOrmation file commonly found on DVDs. Such files contain navigational information for your DVD player. For more info refer to the DVD structure article.

    Interlaced

    Interlaced is a video storage mode. An interlaced video stream doesn't contain frames (pictures as we know them) but fields with each field containing half of the lines of one frame (all even or all odd lines). More info in video storage modes and interlacing can be found in video basics.

    Interleaving

    Imagine gluing together the audio and the video track at defined points, that's about it. The player will recognize the interleave points and make sure that both audio and video are played in a manner that the "glued" points match thru the movie.

    A more detailed explanation: Imagine we have 10 seconds of video and 10 seconds of audio. Let each second of video be represented by a V and each second of audio by an A. If you have an interleaving setting of 10 seconds the file on the disc will look like this: VVVVVVVVVVAAAAAAAAAA. Now if you have an interleaving setting of 1 second instead here's what you get: VAVAVAVAVAVAVAVAVAVA.

    Inverse Telecine

    The inverse of Telecine. This process is performed to extract the original 24fps of a 29.97fps source. 

    Keyframe

    Un frame (cuadro) completo pero altamente comprimido.

    m1v/m2v

    These two terms are used as extensions for MPEG-1 respectively MPEG-2 video data (video only, without any audio).

    miniDVD

    miniDVD is basically a DVD on a CD. A miniDVD can contain bitrates up to 10mbit/s (audio and video combined). Video is MPEG2 of course.. preferably VBR and audio can be MPEG1 audio layer 2, raw uncompressed PCM or AC3. Video quality can be up to an actual DVD level if you accept the limited playtime of a CD. You can create DVD-like menus as well. The drawback is miniDVDs will only play on PCs and on a very limited number of standalone players.

    MPEG

    MPEG means Motion Picture Expert Group and it's THE resource for video formats in general. This group defines standards in digital video, among it the MPEG1 standard (used in Video CDs), the MPEG2 standard (used on DVDs and SVCDs), the MPEG4 standard and several audio standards - among them MP3 and AAC.

    MPEG4

    MPEG4 is pretty much a collection of standards defined by the MPEG Group, and it should become the next standard in digital video (mainly for picture phones, streaming media on the Internet and more). MPEG4 allows the use of different encoding methods, for instance a keyframe can be encoded using ICT or Wavelets resulting in different output qualities.

    MPG

    MPG can be either an abbreviation for MPEG or is used as a file extension for MPEG-1 and MPEG-2 video data. It is a container to contain MPEG-1/2 video stream and MPEG1 layer 2 audio (aka mp2 files). MPG containers are also refered to as program streams (PS).

    MM4

    Multiple MPEG 4: A combination of different bitrate encoded files. For instance you could take a 2000kbit/s encode, a 910kbit/s encode and combine the files together, use the lower bitrate file and replace scenes where the quality gets too bad due to a lot of action with the parts taken from the 2000kbit/s one. It also includes the use of both DivX codecs: You can combine DivX low motion and DivX high motion files (and once again you can choose different bitrates).

    Multiangle

    Multiangle is a special feature of the DVD format, allowing the viewer to switch between different views of the same scene. For instance, let's assume your favorite sport on TV is hockey. You've certainly noticed that there are many cameras recording a hockey game. And while the game is interrupted, you usually get to see slowmo scenes from different angles, be it of a goal scene, a foul or whatnot. While watching the game on TV, you only get the see the picture from the camera that the guy in the cutting room wants you to see. Now, if you get your favorite Stanley Cup final on DVD, the disc could include not only the game as seen on TV, but using the multiangle feature, contain the games from all the different perspectives it was recorded from (camera from the ceiling, cameras on the side, cameras from behind the goal), and while you're watching the game, you can press the Angle button on your remote to switch from one camera to another, or in DVD language, switch from one angle to another, and that's what multiangles is all about.

    Multipass encoding

    Before you read on: Currently true multipass encoding is available only for WM8 and MPEG-2 (SVCD & miniDVD). M4C is not true multipass encoding (and read the M4C guide to find out what it is and how it works). An encoder that supports multipass will in a first pass analyze the video stream to be encoded and write down a log about everything it encounters. Let's assume that we have a short clip which starts out in a dialog scene where we have few cuts and the camera stays static. Then it leads over to a karate fight with lots of fast cuts and a lot of action (people flying through the air, kicking, punching, etc). In regular CBR encoding every second gets more or less the same bitrate (it's hard to stay 100% CBR but that's a detail) whereas in multipass VBR mode the encoder will use the bitrate according to its knowledge about the video stream, that is the dialog part gets of the available bitrate and the fighting part gets more bitrate. The more passes the more refined will the bitrate distribution be. In single pass VBR the encoder has to base his decisions on where to use how much bitrate solely on the knowledge of the stuff it previously has encoded.

    Multiplexing

    Usually video and audio are encoded separately. Then you have to join both of them to make a movie that you can play (you can of course play audio and video separately in two players but to get synch would be rather hard). During multiplexing the audio and video track are combined to one audio/video stream. The audio and video stream will be like woven together and navigational information will be added so that the player can example fast forward/backward and still retain synch audio/video. 

    Normalizing

    Normalizing consists of finding the volume peak of a soundtrack, then increase the rest of the soundtrack to the same level. This is usually done at WAV level, that is all variables are integers so the precision is not as good as in DRC. Hence DRC is to be preferred over Normalizing.

    OGM

    OGM stands for OGg Media which is the name of the Ogg container implementation by Tobias Waldvogel. OGM can be used as an alternative to the AVI container and it can contain Ogg Vorbis, MP3 and AC3 audio, all kinds of video formats, chapter information and subtitles.

    PGC

    PGC abreviación para ProGram Chain (Cadena de Programa). Es un termino comúnmente utilizado en la autoria DVD. Es básicamente un artículo concurrente en la reproducción. Por ejemplo la película principal tiene su propio PGC, cada "corto" en un DVD tiene generalmente su propio PGC. El logo del estudio, y la advertencia legal también tienen su propio PGC, etc. Tanto SmartRipper en "Movie mode" como DVD Decrypter en "IFO mode" te mostrara todos los PGCs que el DVD tiene. Para mas info acerca de los PGCs visita MPUCoder's DVD information site.

    Program Stream (PS)

    A program stream is a combination of elementary video and audio streams (ES). An MPEG-1 program stream contains MPEG-1 video and MPEG1 layer 2 audio (mp2) whereas an MPEG-2 program stream contains MPEG-2 video and MPEG1 layer 2 audio (mp2).

    Progressive

    The opposite of interlaced. A video stream consisting of only full frames is considered progressive. More about progressive and interlaced can be found in video basics.

    PUO

    PUO means Prohibited User Operations. It's a feature of the DVD format, allowing the person doing the authoring to prevent the user from executing certain functionality. For instance, you could activate a PUO that prevents people from fast forwarding / skipping an FBI warning before the main movie starts. Or, it could be used to force you to use the menu of the disc to change the audio language, by setting the PUO for audio switching (so the audio button on your remote won't do anything).

    Quantizer

    To truly understand this term you'd have to take a course in signal processing. In laymen's terms it means compression factor. The higher this value the more compressed an image is (and therefore a high quantizer means low quality picture and small size whereas low quantizers means high quality picture and larger size).

    RCE

    RCE means Region Code Enhancement. Using the programming options that the DVD format offers (reading and writing to a number of registers available in all players), RCE is a more advanced version of region codes. It's a way studios try to prevent you from playing discs that are not sold in your region (don't have a matching region code). Old regionfree hardware players might have problems with RCE discs, but most modern regionfree players have no trouble playing such discs. Currently, discs using RCE use RCE-3 but I don't know if this means it's the 3rd version, or if the 3 has another meaning.

    rff/tff flags

    RFF means repeat first frame, it's a technique used to make the necessary 29.97 frames per second out of a 24 frames per second source - the movie like it was recorded with a traditional movie camera used by Hollywood. The rff flag tells the player to repeat one field of the video stream. Tff means top field first and is also used to perform a telecine to make a 24fps movie into 29.97fps. You can read more about film to video transfer in Robshot's article on synch. 

    Ripping

    Lots of confusion about that one. Basically ripping means copying a DVD movie to your hard disk. This includes the authentication process for the DVD Drive (try to copy a file off a DVD and you'll get a message that this operation is not supported if your drive hasn't been authenticated) and the actual CSS Descrambling. CSS (Content Scrambling System) is a copy protection scheme designed to prevent unauthorized copying of DVD movies, although many argue that it was also designed to control where DVD movies can be played since without a CSS license you essentially have to crack the encryption to play a DVD movie - and I quite agree with that. The term "ripping" is also often used (even on this site) to describe the whole process of descrambling a DVD, then convert the audio and video into another - lesser -  format.

    SBC

    Smart Bitrate Control. A new kind of DivX encoder called Nandub can modify many internal codec parameters on the fly during compression, giving you better quality and a lot more control over the encoding session. More information can be found in the SBC guide in the DivX guides section.

    Streamlist

    A streamlist is an ASCII test file that contains the pathnames and filenames of your VOB files, one file on every line. Here's a small example:
    e:\video_ts\vts_01_1.vob
    e:\video_ts\vts_01_2.vob
    e:\video_ts\vts_01_3.vob
    e:\video_ts\vts_01_4.vob
    e:\video_ts\vts_01_5.vob

    Save this file as streamlist.txt, or streamlist.lst. Make sure that you save it as unformatted ASCII text, I suggest you use notepad to edit your streamlists, since notepad won't save in another format. Mpeg2avi needs the streamlist to have the extension lst, whereas you're free to chose any other extension for other programs that use a streamlist. However the GUI is kind of limited in its choice for input files/extensions, therefore you might have to rename your streamlist, if it doesn't show up in the file selection dialog. 

    SVCD

    Super Video CD, mainly used in Asian countries. Uses MPEG2 Video and therefore much better image quality - LaserDisc-like and also offers High quality surround sound. Furthermore it can take advantage of hardware decoders and there are players for many operating systems. However there are only a few - mostly Asian made low-end - DVD player that can play SVCD and other than SVCD player which are not sold in the US and Europe you can only play SVCDs on your computer. Video is MPEG2 at up to 2600kbit/s and audio MPEG1 audio layer 2 up to 224kbit/s. MPEG2 multichannel audio is also possible, but most players will only output 2 channels and those that will pass through 5.1 audio still require that you have an mpeg2 multichannel capable receiver.

    Telecine

    A process to bring a 24fps source (usually a movie is shot at that speed) to 29.97fps or 29.97x2 interlaced fields per second. Please read this article on how the conversion actually works.

    VBR

    Variable BitRate. It's possible to encode both audio and video in VBR mode, which won't use the same bitrate for the whole file (as in CBR = Constant BitRate) but rather more complicated parts of the video/audio will receive more bitrate in order to look/sound better and less demanding parts will get less bitrate.

    VCD

    Video CD, works on many DVD players, there are software players on almost every operating systems, doesn't need a fast computer but the image is VHS-like. Video is MPEG1 at 1150kbit/s and audio MPEG1 audio layer 2 at 224kbit/s.

    VKI

    Variable Keyframe Interval. Basically that means that keyframes will not be inserted in regular intervals as in the regular DivX codecs but where they are needed. There are 2 ways of VKI: The first is that the encoder analyzes the compressed frame, compares it against the original and re-encodes the frame again as a keyframe if the quality difference is higher than a set threshold. This way of encoding is only possible with a certain special application: M4C. There's a command line based version and a plugin for AviUtl available (the latter is described in detail in the AviUtl guide). If you set the threshold too high you'll end up with a lot of keyframes. Then there's the 2nd way which is basically keyframe insertion at scene changes. In order to do that the encoding program or the codec will detect when there's a cut (as it's called by movie makers) occur and make the first frame of the new scene a keyframe. This can be achieved by using mpeg2aviAr (part of AviRevolution 2.1), m4c or by installing the DivX VKI codec. If you use the latter you don't have to worry about the encoder... every program that can encode to DivX will then result in files that has keyframes at scene changes. VKI, when properly used (that applies to the first way), can help you increase quality and reduce the amount of keyframes, which may lead to higher quality again because especially at lower bitrates too many keyframes will give you a worse quality.

    VM2

    Short version of VKI + MM4 + VBR MP3

    VOB ID

    VOB IDs are used to internally group cells in a PGC on a DVD.

    VOB Files

    All DVD movies are stored in so-called VOB files. Vob files usually contain multiplexed Dolby Digital Audio and MPEG2 video. Vob Files are called 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 never contain any video, usually just menu or navigational information. There's 2 ways to find out which files contain the main movie: First: Play the movie in any DVD player and watch the LED on a standalone or the status window on a software player. Second: The main movie is the largest number of consecutively numbered VOB files. For instance it's vts_05_1.vob, vts_05_2.vob.... vts_05_8.vob (I haven't seen movies with 9 partial files but that doesn't mean that they don't exist). 

    VTS

    VTS stands for Video TitleSet and means a set of consecutively named VOB files with the corresponding IFO and BUP files. For instance VTS2 would be VTS_02_0.VOB (containing the menus), VTS_02_1.VOB, VTS_02_2.VOB, etc, VTS_02_0.IFO and VTS_02_0.BUP. VTS are used to group video stuff together that belongs together. For instance one VTS is usually used for the main movie (sometimes including the trailer and some studio logos), other VTS are used for extras.

    Wavelets

    Wavelets are an alternative basis space. There are infinitely many wavelet bases (Daubechies, Haar, Mexican Hat, "Spline", Zebra, etc), but their primary feature is that they are localized. Fourier basis functions span all space (from negative to positive infinity). Wavelets are basically individual pulses of waves (at various positions and scales).

    Their value in compression stems from factors like the grouping which generally shows that a good 90% of the data is modelled by the low-pass filters, with the high-pass filters generally showing very small values that are mostly details. (of course, this is not true if the source is noisy in the first place). For images, the greatest value comes from localization of the basis, which means that we can model discontinuities (e.g. edges) VERY well with wavelets. You will NOT get those weird JPEG halos if you use wavelets.

    Windows Media

    Microsoft's proprietary architecture for audio and video on the PC. It's based on a collection of codecs which can be used by the WindowsMedia Player to play files encoded in any supported format. There are 3 released of the WindowsMedia codec architecture: version 7, 8 and 9. Those codecs are natively supported by the corresponding media player version (Windows Media Player 7, Windows Media Player 8 supports WMV8, and Windows Media Player 9 supports WMV9), but you can also find codecs pack for download at microsoft.com to play such content outside the official Microsoft media player.

    XCD

    eXtended CD is an upcoming CD format which allows your CDs to be written in mode2 form 2 mode which basically means that it contains less error correction codes thus allowing you to store more data onto a single CD. XCD allows you to store 800 MB of data on a regular 700 MB CD. But as there's less error correction on the discs, XCDs are not very scratch resistant and it's suggested that you only put data that has additional error correction in the container (for instance OGM) on such CDs. For more info refer to the XCD guide.

    XviD

    XviD is a word play, read it the reverse way and you might find a familiar term. XviD is an open source MPEG-4 codec which depending on whom you're asking yields even better quality than the best DivX codec. The XviD homepage can be found here.

    Última Actualización: 26 de Marzo del 2003.