21-09-2012, 10:34 AM
VIDEO COMPRESSION
video compression ppt_ankita.pptx (Size: 172.66 KB / Downloads: 29)
INTRODUCTION
Why video is compressed?
Raw video contains an immense amount of data
Communication and storage capabilities are limited and expensive
To reduce redundancy and irrelevancy
Types of redundancy:-
Spatial Redundancy: Neighboring pixels in a video frame are highly correlated with each other.
Temporal Redundancy: Corresponding pixels in neighboring video frames are correlated.
Psycho visual Redundancy: Some details in video frames are not perceptually important to the human eye.
BASIC BUILDING BLOCKS OF COMPRESSION
Video clip contains a series of still images(frames). Hence, still image compression techniques may also be employed during video compression. Therefore we begin our discussion by explaining the inner working of transform based digital image compression algorithms like JPEG.
BASIC BUILDING BLOCKS OF COMPRESSION
Video compression:
Main addition over image compression is exploitation of temporal redundancy
Here current frames are predicted based on previously coded frames
Three types of frames are used:
I–Frame: Intra coded frames, coded independently of all other frames.
P-Frame: predictively coded frame, coded based on previously coded frame.
B-Frame: Bidirectionally predicted frame, coded based on both previous and future coded frames.
CONCLUSION
Video compression is important.
It is not easy to implement.
Video compression has come a long way but still definitely has room for improvement.
New paradigms in computing will dictate future research directions