Video

Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.

Aspect ratio

Aspect ratio describes the dimensions of video screens and video picture elements. All popular video formats are rectilinear, and so can be described by a ratio between width and height. The screen aspect ratio of a traditional television screen is 4:3, or about 1.33:1. High definition televisions use an aspect ratio of 16:9, or about 1.78:1. The aspect ratio of a full 35 mm film frame with soundtrack (also known as the Academy ratio) is 1.375:1. Ratios where the height is taller than the width are uncommon in general everyday use, but do have application in computer systems where the screen may be better suited for a vertical layout. The most common tall aspect ratio of 3:4 is referred to as portrait mode and is created by physically rotating the display device 90 degrees from the normal position. Other tall aspect ratios such as 9:16 are technically possible but rarely used. (For a more detailed discussion of this topic please refer to the page orientation article.) Pixels on computer monitors are usually square, but pixels used in digital video often have non-square aspect ratios, such as those used in the PAL and NTSC variants of the CCIR 601 digital video standard, and the corresponding anamorphic widescreen formats. Therefore, an NTSC DV image which is 720 pixels by 480 pixels is displayed with the aspect ratio of 4:3 (which is the traditional television standard) if the pixels are thin and displayed with the aspect ratio of 16:9 (which is the anamorphic widescreen format) if the pixels are fat.


Display resolution

The size of a video image is measured in pixels for digital video, or horizontal scan lines and vertical lines of resolution for analog video. In the digital domain (e.g. DVD) standard-definition television (SDTV) is specified as 720/704/640×480i60 for NTSC and 768/720×576i50 for PAL or SECAM resolution. However in the analog domain, the number of visible scanlines remains constant (486 NTSC/576 PAL) while the horizontal measurement varies with the quality of the signal: approximately 320 pixels per scanline for VCR quality, 400 pixels for TV broadcasts, and 720 pixels for DVD sources.

Aspect ratio is preserved because of non-square "pixels". New high-definition televisions (HDTV) are capable of resolutions up to 1920×1080p60, i.e. 1920 pixels per scan line by 1080 scan lines, progressive, at 60 frames per second. Video resolution for 3D-video is measured in voxels (volume picture element, representing a value in three dimensional space). For example 512×512×512 voxels resolution, now used for simple 3D-video, can be displayed even on some PDAs.

Number of frames per second

Frame rate, the number of still pictures per unit of time of video, ranges from six or eight frames per second (frame/s) for old mechanical cameras to 120 or more frames per second for new professional cameras. PAL (Europe, Asia, Australia, etc.) and SECAM (France, Russia, parts of Africa etc.) standards specify 25 frame/s, while NTSC (USA, Canada, Japan, etc.) specifies 29.97 frame/s. Film is shot at the slower frame rate of 24frame/s, which complicates slightly the process of transferring a cinematic motion picture to video. The minimum frame rate to achieve the illusion of a moving image is about fifteen frames per second.

Interlacing

Video can be interlaced or progressive. Interlacing was invented as a way to achieve good visual quality within the limitations of a narrow bandwidth. The horizontal scan lines of each interlaced frame are numbered consecutively and partitioned into two fields: the odd field (upper field) consisting of the odd-numbered lines and the even field (lower field) consisting of the even-numbered lines. NTSC, PAL and SECAM are interlaced formats. Abbreviated video resolution specifications often include an i to indicate interlacing. For example, PAL video format is often specified as 576i50, where 576 indicates the vertical line resolution, i indicates interlacing, and 50 indicates 50 fields (half-frames) per second.

In progressive scan systems, each refresh period updates all of the scan lines. The result is a higher perceived resolution and a lack of various artifacts that can make parts of a stationary picture appear to be moving or flashing. A procedure known as deinterlacing can be used for converting an interlaced stream, such as analog, DVD, or satellite, to be processed by progressive scan devices, such as TFT TV-sets, projectors, and plasma panels. Deinterlacing cannot, however, produce a video quality that is equivalent to true progressive scan source material.

Audio

A digital audio editor is defined as a computer application for manipulating digital audio. There are countless ways that digital audio editor can be used, and fortunately there are plenty of good and free digital audio editors out there that fits our need.

Audacity
Audacity Audacity is free, open source software for recording and editing sounds. It allows you to record live audio, converts tapes and records into digital recordings or CDs, edit Ogg Vorbis, MP3, WAV or AIFF sound files. You also can cut, copy, splice or mix sounds together with Audacity. Built-in effects are given to remove static, hiss, hum or other constant background noises.






Power Sound Director

Power Sound Editor Power Sound Editor Free is a visual audio editing and recording software solution, which supports many advanced and powerful operations with audio data. You can use Power Sound Editor Free to record your own music, voice, or other audio files, edit it, mix it with other audio or musical parts, add effects like Reverb, Chorus, and Echo, and burn it on a CD, post it on the World Wide Web or e-mail it.

mp3DirectCut

mp3DirectCut is a fast and extensive audio editor and recorder for compressed mp3. You can directly cut, copy, paste or change the volume with no need to decompress your files for audio editing. Using Cue sheets, pause detection or Auto cue you can easily divide long files.

Music Editor Free (MEF)

Music Editor Free (MEF) is a multi-award winning music editor software tool. MEF helps you to record and edit music and sounds. It lets you make and edit music, voice and other audio recordings. When editing audio files you can cut, copy and paste parts of recordings and, if required, add effects like echo, amplification and noise reduction.

Wavosaur

Wavosaur is a free sound editor, audio editor, wav editor software for editing, processing and recording sounds, wav and mp3 files. Wavosaur has all the features to edit audio (cut, copy, paste, etc.) produce music loops, analyze, record, batch convert. Wavosaur supports VST plugins, ASIO driver, multichannel wav files, real time effect processing. The program has no installer and doesn’t write in the registry. Use it as a free mp3 editor, for mastering, sound design.

WavePad Sound Editor

WavePad Sound Editor lets you make and edit music, voice and other audio recordings. When editing audio files you can cut, copy and paste parts of recordings and, if required, add effects like echo, amplification and noise reduction. WavePad works as a wav editor or mp3 editor but it also supports a number of other file formats including vox, gsm, real audio, au, aif, flac, ogg and more.

Expstudio Audio Editor

Expstudio Audio Editor is a visual music file editor that has many different options and a multiple functionality to edit your music files like editing text files. With a given audio data it can perform many different operations such as displaying a waveform image of an audio file, filtering, applying various audio effects, format conversion and more.

Ecawave

Ecawave is a simple graphical audio file editor. The user-interface is based on Qt libraries, while almost all audio functionality is taken directly from ecasound libraries. As ecawave is designed for editing large audio files, all processing is done direct-to-disk. Simple waveform caching is used to speed-up file operations. Ecawave supports all audio file formats and effect algorithms provided by ecasound libraries. This includes JACK, ALSA, OSS, aRts, over 20 file formats, over 30 effect types, LADSPA plugins and multi-operator effect presets.

Sweep

Sweep is an audio editor and live playback tool for GNU/Linux, BSD and compatible systems. It supports many music and voice formats including WAV, AIFF, Ogg Vorbis, Speex and MP3, with multichannel editing and LADSPA effects plugins.

Grafik

Grafik (berasal dari perkataan Greek γραφικός) merupakan persembahan visual yang ditunjukkan pada permukaan seperti dinding, kanvas, skrin komputer, kertas, papan untuk tujuan jenama, pemberitahuan, ilustrasi atau hiburan. Contoh grafik ialah gambar foto, lukisan, seni tanpa ton, graf, tipografi, nombor, simbol, reka bentuk geometri, peta, lukisan kejuruteraan atau imej lain. Grafik selalunya menggabungkan teks, ilustrasi dan warna.

Pada masa dahulu, memasukkan grafik merupakan satu kerja yang remah dan rumit. Gambar yang dimasukkan sering kali kabur dan tidak jelas. Namun dengan pelbagai jenis perisian yang canggih pada masa kini, grafik dapat dimasukkan dan di’edit’ dengan mudah mengikut kesesuaian .Perisian seperti adobe photoshop membolehkan penerbit meng’edit’ grafik untuk menjadikannya lebih menarik untuk khalayak umum.

Image Format

This entry is about digital image formats used to store photographic and other images; (for disk-image file formats see Disk image). Image files are composed of either pixel or vector (geometric) data that are rasterized to pixels when displayed (with few exceptions) in a vector graphic display. The pixels that compose an image are ordered as a grid (columns and rows); each pixel consists of numbers representing magnitudes of brightness and colour.

Image file size—expressed as the number of bytes—increases with the number of pixels composing an image, and the colour depth of the pixels. The greater the number of rows and columns, the greater the image resolution, and the larger the file. Also, each pixel of an image increases in size when its colour depth increases—an 8-bit pixel (1 byte) stores 256 colours, a 24-bit pixel (3 bytes) stores 16 million colors, the latter known as truecolor.

There are two types of image file compression algorithms: lossless and lossy.

Loseless
Lossless compression algorithms reduce file size without losing image quality, though they are not compressed into as small a file as a lossy compression file. When image quality is valued above file size, lossless algorithms are typically chosen.

example lossless compression

Lossy

Lossy compression algorithms take advantage of the inherent limitations of the human eye and discard invisible information. Most lossy compression algorithms allow for variable quality levels (compression) and as these levels are increased, file size is reduced. At the highest compression levels, image deterioration becomes noticeable as "compression artifacting".

example lossy compression