This document discusses fundamentals of lossy video compression. It introduces digital video and factors like frame rate, color resolution, and spatial resolution. It describes video compression standards including MPEG, JPEG, H.261, and H.263. MPEG standards like MPEG-1, MPEG-2, and MPEG-4 are discussed in detail regarding their applications and capabilities. The goals of video compression are to reduce file size while retaining quality for storing and transferring video efficiently.

1. FUNDAMENTALS OF LOSSY
VIDEO COMPRESSION
by
ANJU NARAYANAN
Roll No:M17402
M. Tech. in Signal Processing and Embedded Systems
Department of Electronics & Communication Engineering
Govt. College of Engineering Kannur
on
5th November 2018

2. Introduction to Digital Video
 Video is a stream of data composed of discrete frames,
containing both audio and pictures.
 Continuous motion produced at a frame rate of 15 fps or
higher.
 With digital video, four factors have to be kept in mind.
 Frame rate
 Colour Resolution
 Spatial Resolution
 Image Quality
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3. Frame Rate
 In motion pictures, television, and in
computer video displays, frame rate is number of frames or
images that are projected or displayed per second.
 A higher frame rate, more images are shown in same amount
of time and it will reduce motion blur from fast moving
images and will give you better quality crisp video.
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4. Colour Resolution
 It refers to number of colours displayed on screen at one
time.
 Computers deal with Colour in an RGB (red-green-blue)
format, while video uses a variety of formats. One of the
most common video formats is called YUV.
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5. Spatial Resolution
 Spatial resolution is a parameter that shows how many
pixels are used to represent a real object in digital form.
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6. Reasons to compress
 Goal of video compression is to massively reduce
amount of data required to store digital video file, while
retaining the quality of original video.
 Reduce File Size.
 Save disk space.
 Increase transfer speed at a given data rate .
 Allow real-time transfer at a given data rate.
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7. Lossless vs. Lossy Compression
 In lossless compression, data is not altered or lost in the
process of compression or decompression.
 Run-Length Encoding
 Dynamic Pattern Substitution - Lampel-Ziv Encoding
 Huffman Encoding
 Lossy compression is used for compressing audio, pictures,
video.
 JPEG
 MPEG
 H.261 (Px64) Video Coding Algorithm
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8. Lossy compression
 Does not promise that the data received is exactly the
same as the data sent.
 Removes information that it cannot later restore
(Hopefully, no one will notice.)
 Reduce file size by considerably greater amounts than
loss-less compressions but lose both information and
quality.
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9. MPEG (Moving Picture Expert
Group)
 MPEG was set standard for Audio and Video compression
and transmission.
 MPEG-1 is a standard for lossy compression of video and
audio.
 It is designed to compress VHS-quality raw digital video
and CD audio down to 1.5 Mbit/s without excessive
quality loss.
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10. MPEG(contd…)
 MPEG-1 has become the most widely compatible lossy
audio/video format in world.
 It is used in a large number of products and technologies.
 The best-known part of the MPEG-1 standard is the MP3
audio format .
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11. MPEG-2
 It was designed for coding interlaced images at
transmission rates above 4 million bits per second.
 MPEG 2 can be used on HD-DVD and blue ray disc.
 It handles 5 audio channels.
 Covers wider range of frame sizes (HDTV).
 MPEG-2 can compress 2 hours video into a few GHz.
 MPEG-2 is used for digital TV broadcast and DVD.
 An MPEG-2 is designed to offer higher quality than
MPEG-1.
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12. MPEG-3
 Designed to handle HDTV signal in range 20 to 40
Mbits/sec.
 HDTV-resolution is 1920* 1080*30 Hz
 But MPEG-2 was fully capable of handling HDTV so MPEG
-3 is no longer mentioned.
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13. MPEG-4
 MPEG-4 is a collection of methods defining compression of
audio and visual (AV) digital data.
 MPEG-4 absorbs many of features of MPEG-1 and MPEG-2
 MPEG-4 files are smaller than JPEG.
 so they transmit video and images over narrower
bandwidth and can mix video with text graphics and 2D
and 3D animation layers.
 Helps end users with wide range of interaction with
animated objects.
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14. MPEG-7
 MPEG-7 is a content representation standard for
information search.
 It is also titled Multimedia Content Description Interface.
 It will define the manner in which audio-visual materials
can be coded and classified so the materials can be
easily located using search engines.
 Provide a fast and efficient searching, filtering and
content identification method.
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15. Still Image Compression - JPEG
 Defined by Joint Photographic Experts Group
 Released as an ISO standard for still color and gray-scale
images.
 Provides four modes of operation:
 Sequential (each pixel is traversed only once)
 progressive (image gets progressively sharper)
 Hierarchical (image compressed to multiple resolutions)
 lossless (full detail at selected resolution)
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16. H.261 (Px64)
 H.261 was designed for data rates which are multiples of
 64Kbit/s, and is sometimes called p x 64Kbit/s (p is in
the range 1-30).
 These data rates suit ISDN lines.
 Intended for videophone and video conferencing
systems.
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17. H.263 Standard
 The development of modems allowing transmission in
the range of 28-33 kbps paved the way for the
 development of an
 improved version of H.261
 • It was designed for low bitrate
 communication , however this
 limitationhas now been removed
 • It is expected that H.263 will replace H.261
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18. THANKS
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