VDP313XY Ver la hoja de datos (PDF) - Micronas

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Fabricante

VDP313XY

Video Processor Family

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ADVANCE INFORMATION

VDP 313xY

2.5. Horizontal Scaler

The 4:2:2 YCRCB signal from the color decoder is pro-

cessed by the horizontal scaler. The scaler block

allows a linear or nonlinear horizontal scaling of the

input video signal in the range of 0.25 to 4. Nonlinear

scaling, also called panorama vision, provides a geo-

metrical distortion of the input picture. It is used to fit a

picture with 4:3 format on a 16:9 screen by stretching

the picture geometry at the borders. Also, the inverse

effect can be produced by the scaler. A summary of

scaler modes is given in Table 2–1.

The scaler contains a programmable decimation filter,

a 1-line FIFO memory, and a programmable interpola-

tion filter. The scaler input filter is also used for pixel

skew correction (see Section 2.4.10. on page 12). The

decimator/interpolator structure allows optimal use of

the FIFO memory. The controlling of the scaler is done

by the internal Fast Processor.

Table 2–1: Scaler modes

Mode

Scale Description

Factor

Compression 0.75

4:3 → 16:9 linear

4:3 source displayed on

a 16:9 tube,

with side panels

Panorama

4:3 →16:9

non-

linear

compr

4:3 source displayed on

a 16:9 tube,

Borders distorted

Zoom

4:3 → 4:3

1.33

linear

Letterbox source (PAL+)

displayed on a 4:3 tube,

vertical overscan with

cropping of side panels

Panorama

4:3 → 4:3

non-

linear

zoom

Letterbox source (PAL+)

displayed on a 4:3 tube,

vertical overscan, bor-

ders distorted, no crop-

ping

2.6. Blackline Detector

In case of a letterbox format input video, e.g. Cinemas-

cope, PAL+ etc., black areas at the upper and lower

part of the picture are visible. It is suitable to remove or

reduce these areas by a vertical zoom and/or shift

operation.

The VDP 313xY supports this feature by a letterbox

detector. The circuitry detects black video lines by

measuring the signal amplitude during active video.

For every field the number of black lines at the upper

and lower part of the picture are measured, compared

to the previous measurement and the minima are

stored in the I2C-register BLKLIN. To adjust the picture

amplitude, the external controller reads this register,

calculates the vertical scaling coefficient and transfers

the new settings, e.g. vertical sawtooth parameters,

horizontal scaling coefficient etc., to the VDP 313xY.

Letterbox signals containing logos on the left or right

side of the black areas are processed as black lines,

while subtitles, inserted in the black areas, are pro-

cessed as non-black lines. Therefore the subtitles are

visible on the screen. To suppress the subtitles, the

vertical zoom coefficient is calculated by selecting the

larger number of black lines only. Dark video scenes

with a low contrast level compared to the letterbox area

are indicated by the BLKPIC bit.

2.7. Test Pattern Generator

The YCRCB outputs can be switched to a test mode

where YCRCB data are generated digitally in the

VDP 313xY. Test patterns include luminance/chromi-

nance ramps and flat fields.

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