STV2310 datasheet(23/112 Pages) STMICROELECTRONICS

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STV2310

Functional Description

The Flesh Tone Correction mechanism operates with a programmable reference axis. It performs

an on-the-fly change of demodulation axis for any color with a phase of approximately ± 39.4°

around the reference axis. It is only operational in the active video line.

Flesh Tone Correction (c

ϕ) is up to a maximum of ±10°.

Cr and Cb amplitudes can be adjusted separately. (See Section 4.12.1 .)

4.7.2

Programming

For NTSC standards, there are several ways to improve the video input. The hue value is controlled

by the HUECTRL[5:0] bits in the DDECCONT2 register. The hue control value is defined in 63 steps

of approximately 1.4 degrees each, which provide an offset between -45.0° and +43.6°. When

00000, the hue angle is 0, otherwise the value of the hue angle is coded in 2’s complement.

An Automatic Flesh Control is also available with the STV2310. This mode is enabled by setting the

FLESH_EN bit in the DDECCONT10 register. For the Automatic Flesh Control Phase Shift

selection, the Flesh Tone Reference Angle in the [B-Y, R-Y] axis system is either 123° or 117°. This

value is selected in the FLESHPH_SEL bit of the DDECCONT10 register.

The Color Kil control mode can be automatic, depending on the standard identification, or forced On

or Off by the DEM_CKILL_CTRL[1:0] bits in the DDECCONTD register. In PAL/NTSC mode, it can

also depend on burst amplitude by setting the in the DDECCONTF register.

A pedestal can be removed from the luminance input signal by the video standard using the

PEDESTAL_REMOVE bit in the DDECCONT2 register.

4.8

Soft Mixer

4.8.1

General Description

The Soft Mixer is used to mix the Y, Cr and Cb data flows (respectively) from the CVBS source and

the RGB Insertion block. The mixing of the data flows is controlled by Fast Blanking mode. A forced

CVBS or RGB flow mode can also be programmed. In this case, the mixer acts as a multiplexer. A

static mixing (also called alpha blending) mode is also programmable.

When the normal mixing mode is programmed, the CVBS and RGB flows are blending according to

the Fast Blanking (FB) signal. The FB signal is sampled with subpixel accuracy to ensure correct

mixing. The mixing slope between flows is programmable.

Figure 13: Phase Correction when Automatic Flesh Control Enabled

Input Subcarrier Phase

Phase Correction (c

ϕ)

ϕ0

ϕ0 + 29.5°

ϕ0 - 29.5°

ϕ0 + 39.4°

ϕ0 - 39.4°

(degrees)

ϕ0 = 123° or 117°

+10

-10

STV2310 数据表(PDF) 23 Page - STMicroelectronics

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