Wednesday, December 29, 2010

Weak current College】 【video related terminology list (1)】.



AAC

Full name of the advanced audio coding AAC (AdvancedAudioCoding), will be the AC3 audio encoding alternatives. On the basis of the AC3, AAC from various aspects to be improved. (But) the current player and hardware for this upcoming audio format support is still very limited.

Authentication certification

In a movie to play previously, players and discs must be established between a they pass each other in which the real movie information secure means of communication. In this way, on the other hand they also need to ensure a legitimate "audience"--this can be through a number of key key exchange, authentication, and so on method to complete.

AC3

AC3 (AudioCoding3 audio coding 3) is a synonym for Dolby Digital, Dolby Digital is an advanced audio compression technology, it can be up to six bit rate up to a separate channel 448kbps be encoded. To learn more see Dolby website Dolbywebsite.

ASF

The full name of advanced streaming format (AdvancedStreamingFormat), Microsoft and RealMedia streaming corresponding general format.

AVI

Audio video interleaved with each other, in the Windows operating system for personal computers in the most widely used video formats. It illustrates how video and audio without explicitly specifying the encoding/decoding of mutually dependent.

BUP files

BUP file is a backup of the IFO files. These files are generally appear in the DVD disc.

Cell(ID)

A cell is a DVD's smallest video units-is usually used to store a chapter, can also be used to store a chapter (chapter), can also be used to deposit a smaller units, such as multiple perspectives or branches plot information.

Codec codec

Codec is a software that is typically used to encode the audio or video into a specific format, or you can use this specific format for encoding and decoding of the media again. Popular codec: MPEG1, MPEG2, MPEG-4, Indeo, etc. AVI, ASF, etc. just one format instead of encoding/decoding-they can use a different codec encoding.
DAR

DAR said display aspect ratio, it represents the dimensions of the screen. Most of the computer screen aspect ratio of 4: 3, which means (screen) horizontal size is the vertical dimension of 4/3. For the TV screen, the traditional 4: 3 display mode, but now 16: 9 image style more and more, as everyone knows, the 16: 9 display modes in the same diagonal length of more than 4: 3 image rendering out a broader vision. 16: 9 screen more suitable for performance of the Hollywood movie, the movie (image aspect ratio), usually 1: 2.35 or 1: 1.85 (mean image horizontal size is the vertical dimension of 1.85 times).

Deinterlace

Take interlaced video stream to the process is called progressive deinterlacing.

Demultiplexing inverse multiplexing

And multiplexed on the contrary, in the multiplexer, a merge of audio/video streams will be split into several components of its stream (a video stream, at least one audio stream and a navigation flow). Each VOB encoder will encode the VOB file (fast Mpeg encoding mpeg encoding to encode avi, dvd to mpg, second Mpeg2 encoding) inverse multiplexing before, while the DVD player will do the same thing (audio and video will be different in the personal computer to be processed in the process, or be different decoders decode).

Descrambling

DVD is CSS (algorithm) encryption too-just imagine you as each letter number such as 1 to represent a. A sentence becomes a set of numbers, this is what we call encoding, course, CSS is better than this (complex), but it is not difficult to crack. Decrypt means that the process of encrypting in reverse, we get the numbers back into a sentence, or our movie playback again. You can in your DVD drive is authorized after try to copy a movie to your hard drive, and then play, you will get a picture of chaos (cannot view) of the image because it (data) is still encrypted. General CSS decryption they will use a pile of known solutions of keys (such as DeCSS or DODSrip-they contain a large number of keys but naturally not all) or try to use the algorithm attacks (crack) keys (VobDec-why it will work on most of the CD because it does not depend on the disc).

DigitalVideo digital video

General digital video is compressed, because storage is an uncompressed movies take up considerable bytes-1000 G byte (measured by numbers from ten of the 12-th byte). Because General lossless compression for video (storage) is powerless, and so video coding/decoding had to remove non-critical information-some people saw no or is not likely to see. Because the use of key-modern compression algorithm is still not enough, it use keyframes (keyfraMes), I and P frames (IandPframes) to save space.

DivX

God, don't let CircuitCity & # 39; 98 is described in the now obsolete DIVX (DIgitalVideoeXpress digital video experience) system to confused. Now there are two different flavors of DivX: DivX;) is already compromised Microsoft MPEG4 encoder/decoder (Windows Media Video V3) name. The codec is a Microsoft Windows Media for his development of the schema, it is initially used to decoding AVI and ASF formats, but all non-beta versions have been added, allowing AVI lock will not be able to use them for AVI encoding and is only a very few tools support the ASF format. DivX author who is made to remove AVI lock is that they can be reused for encoding AVI, DivX the name replaced because in order to avoid confusion with numerous codec, so that on the same computer simultaneously using crack too and not break the Windows Media Encoder (WindowsMediaEncoder) becomes possible. The latest version of the DivX also includes a has been solved by the Windows Media encoder/decoder for audio, called DivX audio. Because it's broken for now is not so perfect, so use it to carry out high-bitrate encoding will be limited. This codec is also called DivX3.
Another DivXNetworks DivX is developed by the new MPEG-4 video encoder/decoder. It provides more advanced coding control and second encoding. Better is that he can play the older DivX;-) (DivX3) film. This codec is generally referred to as DivX4.

DIVX

DIVX basically took out all the Extras DVD: complimentary things, production group, trailers, multilingual, CircuitCity with a bunch of Hollywood greedy lawyers are full screen movies so you can fully control control film distribution to end users but also at home and play a movie can get control. DIVX is a pay-per-view, and can play DIVX DVD player must be the same as your phone line connected together, when you play DIVX Player when the phone is switched on through the DIVX central machine to register and use your credit card billing. Here is a look at the cost of a movie: 4.50 $ 48-hour film viewing hours; $ 2.50 spectator for outside. DIVX service within one year because the authorization (Warner, Sony, the new route as well as all other smaller production company direct refusal to provide authorization in this format--is very grateful to them!!), and mainly from the DVD site on the Internet and terminated in a widely criticized. Newspapers and TV news later this was serious coverage.

Because DIVX use triple DES encrypted so it is not afraid of key attack, very safe. Unless you can crack it, otherwise you can't rip the disc. In other words your DIVX discs ever become a mainstream.

DRC

Dynamic range compression (DynamicRangeCompression). AC3 track contains most of the audio device is able to handle dynamic range compared to a larger dynamic range, so most DVD players and DVD playback software will follow the actual dynamic range in the compresses them to some extent. Non-specialized terms, the volume at a time will be increased. For example, noise does not become bigger, but just a little bigger, but general dialogue volume will increase a lot. Because your player will do, this is the way to increase volume.

Field-field

Interlaced video stream (Interlacedvideostreams) contains a field instead of frames (frames).

FourCC

FourCC represents four-character code (fourcharactercode), is an independent label video streaming format, four-character code. Video playback software by querying the FourCC code and look for FourCC code associated with the video codecs to play a particular video stream. For example: DIV3, DIV4 = = DivXLow-Motion DivXFast-Motion, DIVX = DivX4.

FormatsusedforDVDconversionDVD using format

VCD: VideoCD, in many DVD players can play on almost every operating system has the appropriate player software. Play this disc does not require a fast computer, but the image quality and VHS. Its video is 1150kbit/s MPEG1, audio is MPEG1audiolayer2 224kbit/s.


SVCD: SuperVideoCD, in Asian countries. Video section use MPEG2, LD's image quality, while providing high-quality surround sound. In addition, it also can make use of the advantages of hardware decoder, many systems have playback software. However, only a few Asian manufacturing of low-end DVD player can play SVCD, in Europe and the United States is not such a player, you can only look on your computer. Video use highest 2600kbit/s of MPEG2, audio use MPEG1audiolayer2 224kbit/s. Although you can also use MPEG2 multichannel audio, but it can only be used on Linux, and because of this formatSupports very few, it's hard to say most of the players can not play this kind of MPEG2 musictrack 5.1 channel. At the same time, this disk can provide menu.

MiniDVD: can be stored on the CD DVD, bit rate maximum 10mbit/s (including video and audio). Video part adopts MPEG2 VBR audio section, can be MPEG1audiolayer2, rawuncompressedPCM or AC3. If you are willing to accept the limitations of the playback time, video quality and DVD. You can also establish DVD-like menus. The disadvantage is miniDVD can only play on a PC, in need of your upgrade AffreyLD2060 player to get the ability to play the miniDVD.


DivX/MPEG4: depending on your choice of resolution and bitrate, the video quality from lower than VHS to near DVD. You can choose a variety of audio formats. You can make very like DVD DivXCD: multi language, subtitles, menus, while the heavy workload. In addition, although there is no player can put DivX, but basically all operating systems can play, including Mac, Linux, BeOS, and of course Windows. But there are a lot of strange problems, slow machines working, but in the fast jump-on the machine, and so on. But if he's working on your machine, then it is your choice.

Frame frame

The basic unit of the film. A frame represents a picture image. Film is usually played 24 frame 1 seconds, so it's 1 second 24 pieces of different images. Imagine 24 bird image, in the first picture of the bird is on the left side of the diagram, and then it gradually move to the right. In the first 24 frame a bird is already in the far right of the image. Imagine this 24 images fast enough to play sequentially, so people glance as if the bird fly from the left side of the screen to the right.

IandPFramesI frames and P-frame

The current frame (Frame) just describe it and the differences between the previous frame (though not very accurately described but believe understanding meaning not difficult). For example, we have a picture of a bird flew over a cloud in the sky image, this is a key frame (keyframe). And then we can use the I-frame to this description: will the bird to the left and below the move an inch.

IDCT & WaveletiDCT and Wavelet

MPEG file in the video information is stored in the frequency domain and non-spatial domain (that is, we see the image). Information in this way are compressed to reduce the amount of information in the communication channel. MPEG DCT through discrete cosine transform (DiscreteCosineTransform) spatial information transform into frequency domain information. Extract from the MPEG stream out space domain information, we require the use of inverse discrete cosine transform (IDCT) to offset the encoding of discrete cosine transform.

DCT and IDCT is actually a discrete Fourier transform (DFT), but we got through the DFT is plural, DCT/IDCT transform the result is an integer. We can in the DSP, communication systems, and other areas of university textbooks in to more detailed information.

Wavelet is a space. Wavelet bases can be infinitely kind (for example, Daubechies, Haar, MexicanHat, "Spline", Zebra and so on), but the main features of wavelet-based is that it is localized. Fourier function spans the entire space (from negative infinity to positive infinity), and Wavelet actually different locations, different scale of pulse wave.

Compression of the data into the future. Generally speaking, more than 90% of the data through a low pass filter, high pass filter will filter out numerical very small detail data (of course, if the information source of the noise, then this naturally not established). For images, use the method of maximum value to the base of localization, so we can use Wavelet to very good simulation like edge these non-consecutive parts. Using Wavelet later no longer appears strange JPEG aura.

IFO files

Information file (InFOrmationfile) usually exist and DVD. These files contain the DVD player navigation information.

Interlaced interlaced

Interlaced (interlaced) is a video storage mode a interlaced video stream does not contain frames are some of the field, each field contains a frame in the half of the number of rows (all is odd or even all).

Interleaving interlaced

Imagine in a specific point in the audio and video together, is what we call a jagged. Player will recognize cross point, ensure that the audio and video in a movie, in accordance with the laws of the point to play.


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