Data Compression


Criteria

Survey Formats

Basics

Compression Methods

Data Formats

Files

Audio Data

Image Data

Video Data

MPEG

Principle of MPEG

Picture Types

Intra Pictures

Predictive Pictures

Bidrectional Pict.

DC Pictures

Sequence of Pictures

Decoding

Processing and Archiving


Glossary

Index


Download


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Picture Types


The MPEG standard specifies four picture types which differ regarding compression efficiency and access behaviour:


I-Pictures - Intra Coded Pictures

I-pictures are completely coded and does not refer to preceding or succeeding pictures.


P-Pictures - Predictive Coded Pictures

The picture's contents is derived from a preceding picture, changes are coded by its difference in combination with motion compensation. P-pictures can only be represented, if the original pictures are still accessible.


B-Pictures - Bidrectionally Coded Pictures

B-pictures will be derived from both a preceding and a succeeding picture. In principle they represent an interpolation between two pictures.


D-Pictures - DC Coded Pictures

D-pictures contain the entire contents like I-pictures, but are massively compressed. They are intended for fast-forward functions.


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MPEG - Survey The Principle of MPEG Intra Coded Pictures