Sharp DV-500D, Technical Manual

Page: 18 / 117

18
DVD-Series
(2) Movement [Detection]
The system detects each macro block and compares the current picture to the past
memorized ones, and compiles data about the direction and distance of movement vectors.
1 2 3 4 3 4
5
*
6
* * * *
Macro block
Past picture (frame)
Current picture (frame)
Amount of movement
It detects which square (block) corresponds to this one in the previous picture and measures the
moved amount and directional vectors.
(3) Movement Compensation Prediction
There are parts similar in previous and successive pictures. Therefore, it is not necessary
to transfer every bit of information on the current picture, since similar parts of the previous
picture can be used.
To determine what content of the current picture is to be transferred, prediction is made by
comparing the amount and direction of movement in the previously memorized picture and
the current one.
Then, only the parts with margin of error, meaning the parts that changed and/or were
added, are recorded.
Past picture (frame) called f
rom the memory
Past picture, which movement
compensation is made from
movement [detected]
Sending only the unpredicted
information
Current picture (frame)
Movement
compensation