Data dan Teknologi Multimedia Sesi 06 Nofriyadi Nurdam

At the end of this session, the students will be able to:  Show how to use video on multimedia application.

 Analogue Video  Digital Video  Video Manipulation  Standard Broadcast Video  Working with Video

Movies from Film Analog Video Digital Video

Movie From Film  Sequential image frames are recorded on film using a light sensitive technology similar to still photography.  Film must be chemically developed

Movie From Film  Editing requires physically cutting and splicing the film

 Video information that is stored using television video signals, film, videotape or other non-computer media  Each frame is represented by a fluctuating voltage signal known as an analogue wave form or composite video.  Composite analogue video has all the video components: brightness, colour and synchronization  Then, combined into one signal for delivery  Usage : television  Problems: colour blending, low clarity, high generation lost, difficult to edit

Analogue video editing  Analogue tape editing is a linear process ◦ To find the section you want, you may have to forward or rewind the video tape ◦ To move a section to another place in the sequence you have to either re-record the section onto another tape or physically cut and splice the video tape

 Digital video is the digitisation of analogue video signals into numerical format  It creates the illusion of full motion by displaying a rapid sequence of changing images on a display device.  Conversion from analogue to digital format requires the use on an ADC (Analogue to Digital Converter)  A Digital to Analogue Converter (DAC) can be used to output digital video on analogue equipment

Digital video editing  Digital video editing can be non-linear process ◦ You can move sections around inside the computer and play those sections back in any order

File Size Considerations  Frame rate ◦ Number of images displayed within a specified amount of time to convey a sense of motion ◦ Usually measured in frames per second ◦ Standard video movie  30 fps ◦ Movie film  24 fps ◦ Video digital  at least 15 fps ◦ Computer?

Bina Nusantara File Size Considerations  Frame or Image size ◦ The width and height of each individual frame or image ◦ Determines the quality of the image displayed and the processing involved to display that image ◦ Standard full screen resolution is 640x480 pixels ◦ Video screen display is one fourth the size of the full window screen (320x240)

File Size Considerations  Color depth/Resolution ◦ Number of colors displayed on the screen at one time ◦ Ranging from 1 bit to 8 bit, 16 or 24 bit per pixel

File Size Considerations  Quality directly related to frame size and color depth.  Quality also depends on content. Motion picture needs higher frame rate  File size depends on quality and duration File SizeQuality Frame SizeColor DepthFrame Rate Duration

File size = Frame Size x Frame Rate x Color Depth x Time  Where: ◦ Frame size = image size ( width x height in pixels) ◦ Frame rate = frames per second ◦ Color depth = measured in bytes ◦ Time = time in seconds This does not include any sound data !

 Since the size of raw digital video is so prohibitively large we need some means to compress the information  Video compression and decompression program, known as Codecs  Lossy compression techniques cause some information to be lost from the original image ◦ Redundant information ◦ Example: Image and video  JPEG and MPEG  Intraframe and Interframe  Lossless compression techniques do not lose information throughout the compression and decompression process ◦ Example use in text images  Exactly same before and after compression  Technique is identify repeating words and assign them a code.  Decompression, the code would be changed back to the actual word.

Interlace d video

 NTSC ◦ North America, South America, Japan ◦ 525 interlaced resolution lines ◦ 30 frames per second (fps)  PAL (Phase Alternate Line) ◦ Australia, South Africa, Europe ◦ 625 interlaced resolution lines ◦ 25 frames per second (fps)  SECAM ◦ France, Russia ◦ 625 interlaced resolution lines ◦ 25 frames per second (fps)  HDTV ◦ Six different formats ◦ Aspect ratio is 16:9

.MOV signifies Quicktime, an Apple standard. It is playable on Macintosh and Windows machines. .AVI is a Microsoft standard that is playable on Windows and Macintosh machines. .MPEG (.MPG) is playable on Unix and Windows machines. Macintoshes can play MPEG, but may have trouble with the audio track. .RM files are used by RealNetworks streaming. They are playable on Windows, MacOS, and Unix computers. .ASF files are a Microsoft streaming format, and play on Windows, MacOS, and Solaris. .WMV files are a Microsoft format used in Microsoft MovieMaker

 Named after the Moving Picture Experts Group who devised the compression and file formats  There are a number of MPEG formats: ◦ MPEG-2 is used for digital TV broadcasts and DVDs ◦ MPEG-1 is a format used for low quality video (generally displayed on computers)  MPEG-1 Layer 3 is the popular encoding mechanism for MP3 audio files (more on this later in this course) ◦ MPEG-4 is a new format for multimedia presentations  Can require separate hardware to decode higher quality MPEG video data

A simple scene showing a car moving across a desert landscape Only the difference between the current and next frame needs to be stored This is called interframe coding

 Developed by Apple, Inc.  Primarily for playback without any hardware assistance  Can achieve compression ratios of 25 to 200:1  The QuickTime format can also store audio, graphics, 3D and text making it more much versatile for multimedia applications

 Audio Video Interleave format  Interleaving is a technique used to embed two or more things into the same stream of information  In every chunk of information you will find some video data and some audio data Video information Audio information 8, 16 or 24 bits

 Typified by the Apple iMac DV computer  IEEE 1394 or FireWire interface  Digital camcorders Bina Nusantara

 Showing physical procedures. Some uses are: ◦ Installing a board in a PC ◦ Adjusting engine timing  Attracting and holding attention. Some uses are: ◦ Advertising products and services ◦ Teaching new skills to busy employees  Presenting scenarios. Some uses are: ◦ Training technicians to respond to equipment malfunctions ◦ Demonstrating possible uses for a product  Analyzing motion. Some uses are: ◦ Body motion to improve athletic performance ◦ Traffic patterns for transportation planning

 Carefully planned, well-executed video clips can make a dramatic difference in a multimedia project  Use video only when all other methods (text, still images) are not enough; don’t use it just because it’s possible  Video adds visual impact to multimedia applications: ◦ Advantages  Captures interest  Increase retention  Clarifies complex physical actions and relationships  Can incorporate other media ◦ Disadvantages  Is expensive to produce  Requires extensive memory and storage  Requires special equipment  Does not effectively illustrate abstract concepts and static situations

Q&A