Digital video
- 1. DIGITAL VIDEO Presented by M.LAVANYA M.sc(CS & IT) Nadar Saraswathi college of arts & science, Theni.
- 2. DIGITAL VIDEO • Digital video combines features of graphics and audio to create dynamic content for multimedia products. • Content for digital video originate from video camera or film that has been capture and digitized for the computer. • It may also be created by putting graphic image together to create animation.
- 3. BACKGROUND AS VIDEO • Video is simply moving pictures. The moving pictures offer momentary glimpses of time frozen from one frame to the next. • The most common forms of video are movies and television. Movie use film to present a series of images. Television uses a series of electronically transferred images. • Digital video is used to capture content from movies and television to be used in multimedia product.
- 4. SOURCES OF DIGITAL VIDEO Digital video can consist of much more than movie can taken from existing film resources, it can be also include: • Recording of live action, usually captured with a video camera. • A series of graphic images played in rapid succession similar to a cartoon • Still images taken from film, videotape, or live action.
- 5. Digital video takes on many more forms than a digital movie. Digital video: • Is captured from television ,VCR, and camera sources. • Controllers which are used to control VCR, video disk, camera, and other video devices. • Video capture hardware that accepts video input and turns it into a digital format. • Uses graphic overlay techniques in which digital video images are placed on top of other graphics data on the computer screen.
- 6. TYPES OF ANALOG VIDEO • Several methods are available for the transmission of video signals, the most common form being analog video in the form of television. • Video is represented by a fluctuating voltage signal known as an analog wave form also referred to as composite video. • Compositing analog video including brightness, color, and synchronization combined into one signal. • Compositing results in color bleeding, low clarity and high generation loss.
- 7. • There are number of composite or analog video signal formats for television broadcast include: • NTSC(National Television Standards Committee): NTSC consists of 525 scan lines drawn every 1/30th second on a screen that has a 4:3 aspect ratio. • PAL(Phase Alternate Line): PAL consists of 625 scan lines drawn every 1/25 second.PAL is interlaced at 50 cycles per second. • SECAM(Sequential Color with Memory):like PAL, SECAM uses 625 scan lines and is interlaced at 50 cycles per second.
- 8. Component video: • Component video takes the different components of video such as color, brightness, sync and breaks them into separate signals. • Component video a number of formats such as S-VHS video and RGB have emerged. • S-VHS video is based on storing color and luminance information on two separate tracks. • RGB stores video on separate channels for red, green, and blue color components.
- 9. Digital video: • Digital video solves generational loss because it is a digital representation of the analog video and four communication channel of red, blue, green and luminance stored on 19 mm tape. • The main advantage is that digital video is not subject to generation loss because each copy is identical to the parent. • There is a significant for high quality digital video in the television and movie industries. These industries reply on tape as the means to store and transmit digital video.
- 10. Computer based digital video: • There are two advantages in using computer based digital video: 1. The ability to randomly access the video. 2. The ability to compress the video. • There are number of ways that desktop computer can be: 1. Video overlay board accept video and place it over computer display image. 2. Video capture board is able to accept and connect analog to digital video. 3. Compression hardware or circuitry on video capture board that compress digital video.
- 11. Video capture technology Graphics adapter and display Video overlay-converts video into digital signal Video capture-converts video into digital signal Compression hardware- compresses digital video data Computer storage Video source: camera, VCR Video capture hardware optionsDesktop computer Compressed digital video
- 12. CHARACTERISTIC OF DIGITAL VIDEO • Characteristics as two-dimensional computer graphics including height, width, and color-depth. A frame is a single image in a video sequence and is same as single cel of movie film. Three basic characteristic of digital video: 1. Frame Rate: number of image displayed within a specified amount of time to convey a sense of motion. 2. Frame Size: the height and width of each individual frame of image. 3. Color Depth or Resolution: the amount of color for each pixel within each frame or image.
- 13. CHARACTERISTIC OF DIGITAL VIDEO Video frame 1 Video frame 2 Video frame 3 Frame size: height and Width of a frame Color depth: number of colors per image Frame rate: number of frames displayed over a period of time …
- 14. FRAME RATE • Frame Rate is based on series of image and is usually measured in frames per second. • Videotape is 30 frames per second and photographic movie film is displayed at 24 frames per second. • The frames of movie film called cels are moved past as light source and television depends on electromagnetic scan lines called fields. • There are 60 of these fields displayed every second. This referred to as interlaced video.
- 15. FRAME SIZE • The size of image determines the quality of the image displayed and the processing involved to display that image. Larger images provides improved resolution. • The video graphics adapter (VGA) standards used in computers monitor with resolution of 640 by 480 pixels. The resolution between analog video and computers is different. • Common frame size in digital video include: 640 by 480, full screen VGA display 320 by 240, quarter of a VGA display 240 by 180, about a sixth of a VGA display 160 by 120, sixteenth of a VGA display
- 16. COLOR DEPTH OR RESOLUTION • Depth or resolution refers to the number of colors displayed on the screen at one time. • Computers deal with color in a RGB or red-green-blue format that includes color ranging from 1 bit for 2 colors or 8, 16, and 24 bits/pixel. • Digital video system to use two color strategies: 24-bit color to achieve optimal color reproduction. 8-bit black and white or 256 color for a reduction in file size .