STV2310 datasheet(26/112 Pages) STMICROELECTRONICS

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Functional Description

STV2310

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4.9.1.3 Zoom-Out Mode

In Zoom-Out mode, the entire input TV scan line is compressed to take only a part of the output line.

The active samples are positionned in the center of the output line and the rest of the line is blacked

out. The zoom-out factor ranges from 0.25 (large zoom) to 1 (no zoom).

4.9.1.4 Panorama Mode (Non-Linear Scaling)

To better display wider TV screen aspect ratios, Panorama mode applies a different zoom factor to

the center of the image in relation to the edges; i.e. a Non-Linear Scaling mode must be

implemented. This implies that the compression/expansion factor will vary on the edges and remain

stable at the center. Note in Figure 16 that the resulting TV image is symetrical (right and left edges

are equal).

4.9.2

Programming

4.9.2.1 Square Pixel Mode

Square Pixel mode is enabled by setting the PIXMODE bit in the DDECCONT0 register.

4.9.2.2 Zoom-In Mode

To enable Zoom-In mode, the ZOOMIN_EN bit in the DDECCONTB register must be set.

The zoom-in value must be between 256 and 1023. A value of 512 will zoom-in the picture by a

factor of 2.0; i.e. pixels are twice as large. The zoom-in factor is programmed in the

ZOOMIN_FACT[9:0] bits in the DDECCONT6 and DDECCONTB registers. The default value is 256

(No Zoom).

Figure 15: Zoom-Out Mode

Figure 16: Non-Linear Scaling

720 Samples (Y Normal Pixel Mode)

Black Level

Input Line

Output Line

after zoom

Zoom Factor

Center

Left Edge

Right Edge

Horizontal Axis

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