Transcript Video Formats

Multimedia Systems: ADCS 3
Video
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.
Introduction
• Video standards and formats are still being
refined as transport, storage,
compression, and display technologies
take shape in laboratories and in the
marketplace.
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.
Video Formats
Digital Video File Formats
1. MPEG
2. Quicktime
3. AVI
4. DV
5. DivX
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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.
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Video Formats
Three major MPEG standards: MPEG-1, MPEG-2 and MPEG4.
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.
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Video Formats
Standardised in 1998
MPEG-4
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.
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Video Formats
3. Quicktime
•The QuickTime
format is developed by Apple.’
1
•QuickTime is a common format on the Internet…
•using MPEG-4 video encoding
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Video Formats
4. AVI (Video for Windows)
•The AVI (Audio Video Interleave) format was developed by
Microsoft.1
•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
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frames)
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.
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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.
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