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Multimedia Systems: ADCS 3

Multimedia Systems: ADCS 3. Video. Introduction. Digital video is a powerful tool for bringing computer users closer to the real world.

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Multimedia Systems: ADCS 3

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  1. Multimedia Systems: ADCS 3 Video

  2. Introduction • Digital video is a powerful tool for bringing computer users closer to the real world. • With video elements in your multimedia project it is possible to present your messages and reinforce your story, and viewers tend to retain more of what they see.

  3. Introduction • Video standards and formats are still being refined as transport, storage, compression, and display technologies take shape in laboratories and in the marketplace.

  4. Note • As a multimedia producer, you may need to convert video source material from its common analog form (videotape) to a digital form manageable by the end user’s computer system.

  5. Video Formats • Digital Video File Formats • MPEG • Quicktime • AVI • DV • DivX IT Fundamentals

  6. Video Formats 1. MPEG Family Moving Pictures Experts Group (MPEG) standard for compressing video signals using DCT (Discrete Cosine Transform)…An algorithm that quantifies the human’s eye ability to detect color and image distortion. MPEG uses a type of lossy compression, since some data is removed. But the diminishment of data is generally imperceptible to the human eye. • Discrete cosine transform • a lossy compression algorithm • samples an image at regular intervals • analyzes the frequency components present in the sample, and discards those frequencies which do not affect the image as the human eye perceives it. • the basis of standards such as JPEG, MPEG. IT Fundamentals

  7. Video Formats • Three major MPEG standards: MPEG-1, MPEG-2 and MPEG-4. • MPEG-1 • Video resolution of 352-by-240 at 30 frames per second (fps). • MPEG-2 • Resolutions of 720x480 and 1280x720 at 60 fps, with full CD-quality audio…. • MPEG-2 is used by DVD-ROMs. • MPEG-2 can compress a 2 hour video into a few gigabytes. • While decompressing an MPEG-2 data stream requires only modest computing power, encoding video in MPEG-2 format requires significantly more processing power. IT Fundamentals

  8. Video Formats Standardised in 1998 Based on MPEG-1 and MPEG-2 and Apple QuickTime technology Designed to transmit video and images over a narrow bandwidth and can mix video with text, graphics and 2-D and 3-D animation layers. A major feature of MPEG-4 is its ability to identify and deal with separate audio and video objects in the frame, which allows separate elements to be compressed more efficiently and dealt with independently. MPEG-4 IT Fundamentals

  9. Video Formats • 3. Quicktime • The QuickTime format is developed by Apple.’ • QuickTime is a common format on the Internet… • using MPEG-4 video encoding 1 IT Fundamentals

  10. Video Formats • 4. AVI (Video for Windows) • The AVI (Audio Video Interleave) format was developed by Microsoft. • Interleaving is a technique used to embed two or more things into the same stream of information • A very common format on the Internet • Videos stored in the AVI format have the extension .avi. • 5. DV (Digital Video) • It uses a spatial compression technique (each frame being compressed on an individual basis rather than being compared to adjacent frames) 1 IT Fundamentals

  11. Video Formats • Many newer DVD players are able to play DivX movies. • A typical feature-length movie on DVD is around 7 gigabytes in size; with DivX this can be compressed to around 700 megabytes which fits on a CD-ROM with minimal loss in quality. • Various programs are available which can produce a DivX file from a normal video DVD (this process is known as "ripping"). • The resulting file can then be stored on hard disk, burned on optical media, or shared on peer-to-peer networks. IT Fundamentals

  12. HD DVD • HD DVD • HD DVD (for High Density Digital Versatile Disc) is a digital optical media format which is being developed as one standard for high-definition DVD. • HD DVD is similar to the competing Blu-ray Disc, which also uses the same CD sized (120 mm diameter) optical data storage media and 405 nm wavelength blue laser. • HD DVD is promoted by Toshiba, NEC, Sanyo, and Microsoft, and backed by four major film studios. • HD DVD has a single layer capacity of 15 GB and a dual-layer capacity of 30 GB. • Toshiba has announced a triple-layer disc is in development, which would offer 45GB of storage. IT Fundamentals

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