Introduction to Video

What are some advantages of digital video?

• Single-pass, analog-type impairments are non-cumulative if the signal stays digital. However, a concatenation of digital black boxes using analog interfaces leads to cumulative analog signal degradations and should be avoided.
• There is a reduced sensitivity to noise and interference.
• Digital equipment efficiently and economically performs tasks that are difficult or impossible to perform using analog technology.
• It is amenable to the application of techniques for efficient retention of essential information such as compression.

What is meant by frame rate in video?

A film frame, or just frame, is one of the many single photographic images in a motion picture. The individual frames are separated by frame lines. Normally, 24 frames are needed for one second of film. In ordinary filming, the frames are photographed automatically, one after the other, in a movie camera. In special effects or animation filming, the frames are often shot one at a time.

Are all videos/movies the same frame rate, explain your answer?

No, not all videos or movies are the same frame rate, so videos/movies may be slower by frame thanothers. Like for example an interview or horror movie frames wouldnt go as fast as a non stop action movie.

What is meant by resolution, how is it measured?

Definition: Resolution is the term used to describe the number of dots, or pixels, used to display an image. Higher resolutions mean that more pixels are used to create the image, resulting in a crisper, cleaner image.

The display, or resolution on a monitor, is composed of thousands of pixels or dots. This display is indicated by a number combination, such as 800 x 600. This indicates that there are 800 dots horizontally across the monitor, by 600 lines of dots vertically, equaling 480,000 dots that make up the image you see on the screen.

Examples:

The resolution setting on the computer monitor was set for 800 pixels wide by 600 pixels deep.

How is it measured?:

Resolution is Measured in Pixels

• The resolution of a monitor is measured in picture elements, or "pixels" for short. Pixels are tiny dots that display on a computer monitor in one of millions of colors, shades and hues. To the viewer, the many pixels in a computer monitor combine to form a viewable picture.

Vertical Measurements

• The first consideration in measuring a monitor's resolution is the number of lines displayed on the monitor from top to bottom. While a traditional television display may consist of about 480 lines, higher resolution computer monitors squeeze at least 1080 lines onto the display.

Horizontal Measurements

• Each of the many lines measured in Section Two above is comprised of hundreds or thousands of tiny dots (pixels). Generally, the number of pixels contained in a line is proportional to the number of lines in the monitor's display; more lines means more dots in each line.

Resolution is Measured in Horizontal x Vertical Pixels

• When a monitor's resolution is described, the description generally consists of the number of dots (pixels) contained in each line followed by the number of lines on the monitor. For example, a 1600 x 1200 display would contain 1600 pixels per line and display 1200 lines. An older monitor that displays resolutions of 640 x 480 would display 480 lines containing 640 pixels each. By this measurement, the number of dots per line can be multiplied by the number of lines to identify the total number of pixels displayed by the monitor. Using the examples above, a 1600 x1 200 monitor would display 1,920,000 individual pixels. An older monitor with a resolution of 640 x 480 would display 307,200 individual pixels. Because the individual pixels combine to display a complete picture, a higher number of pixels generally means a clearer picture.

What is the colour system called RGB?

The RGB color model is an additive color model in which red, green, and blue light is added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors, red, green, and blue.
The main purpose of the RGB color model is for the sensing, representation, and display of images in electronic systems, such as televisions and computers, though it has also been used in conventional photography. Before the electronic age, the RGB color model already had a solid theory behind it, based in human perception of colors.
RGB is a device-dependent color model: different devices detect or reproduce a given RGB value differently, since the color elements (such as phosphors or dyes) and their response to the individual R, G, and B levels vary from manufacturer to manufacturer, or even in the same device over time. Thus an RGB value does not define the same color across devices without some kind of color management.
Typical RGB input devices are color TV and video cameras, image scanners, and digital cameras. Typical RGB output devices are TV sets of various technologies (CRT, LCD, plasma, etc.), computer and mobile phone displays, video projectors, multicolor LED displays, and large screens such as JumboTron, etc. Color printers, on the other hand, are not RGB devices, but subtractive color devices (typically CMYK color model).

Explain the video standards PAL, NTSC, and SECAM, what are the main differences between them?

There are 3 main analog video standards in use around the world.
PAL (Phase Alternating Line)
NTSC (National Television System Committee)
SECAM (Séquentiel Couleur à Mémoire—Sequential Color with Memory)
Each standard is incompatible with the other two. Also, the equipment that demodulates the signal must be formatted for that signal.
Generally NTSC is used in North America, most of the countries in South America and Japan. PAL is the format for the UK and most European countries except France and parts of Eastern Europe which use SECAM. For example, a recording made in the France could not be played on an American VCR.
If you view video tapes that are from outside of the United States, or send videos abroad, you must first convert the tape to or from the foreign television standard.
This table illustrates the differences between the video standards:

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	NTSC M	PAL B,G,H	PAL I	PAL N	PAL M	SECAM B,G,H	SECAM D,K,K’,L
Lines/Fields	525/60	625/50	625/50	625/50	525/60	625/50	625/50
Horizontal Frequency	15.734 kHz	15.625 kHz	15.625 kHz	15.625 kHz	15.750 kHz	15.625 kHz	15.625 kHz
Vertical Frequency	60 Hz	50 Hz	50 Hz	50 Hz	60 Hz	50 Hz	50 Hz
Color Subcarrier Frequency	3.579545 MHz	4.43361875 MHz	4.43361875 MHz	3.582056 MHz	3.575611 MHz
Video Bandwidth	4.2 MHz	5.0 MHz	5.5 MHz	4.2 MHz	4.2 MHz	5.0 MHz	6.0 MHz
Sound Carrier	4.5 MHz	5.5 MHz	5.9996 MHz	4.5 MHz	4.5 MHz	5.5 MHz	6.5

What Standard do we use in Australia? What is an IEEE 1394 port?

We pretty much use PAL

a high-speed, serial input/output bus for computer peripherals and consumer electronics, capable of transfer speeds of up to 400 megabits per second.

• PRO: fastest external input/output bus available; supports up to 63 devices at once; optimal for bandwidth-hungry devices such as digital video cameras and external storage devices.
• CON: not as widely implemented as Universal Serial Bus; needs fast CPU.
• Why do digital video cameras use video compression? Firstly Video compression refers to reducing the quantity of data used to represent digital video images, and is a combination of spatial image compression and temporal motion compensation. Video compression is an example of the concept of source coding in Information theory. This article deals with its applications: compressed video can effectively reduce the bandwidth required to transmit video via terrestrial broadcast, via cable TV, or via satellite TV services. Digital Video Cameras use video compression because its easier to store something large.
  
  What is meant by “generation loss”, where does it happen?
  Any time the footage has to be recompressed results in a generation loss. For example, colour correction, super imposed titles, a cross dissolve.Generation loss refers to the loss of quality and potential increase of file size between subsequent copies of data. Anything that reduces the quality of the representation when copying, and would cause further reduction in quality on making a copy of the copy, can be considered a form of generation loss. Mostly in Analog Systems where is most likely to occur is because of the noise that the bandwidth and amplifiers make.
  
  
  Describe what a codec is.
  A codec is a device or computer program capable of encoding and/or decoding a digital data stream or signal.The word codec is a portmanteau of 'compressor-decompressor' or, more commonly, 'coder-decoder'.