STV3550 datasheet(26/144 Pages) STMICROELECTRONICS

26 / 144 page

26/144

STV3550

factor is programmable from 0.25 to 4 for horizontal scaling and 0.5 to 4 for vertical scaling with an

accuracy of 1/8192. This allows for continuous linear zoom variations.

3.3.2.1 Non-Linear Zoom

The rescaling block performs the horizontal and vertical non-linear zoom as shown in Figure 9. The

picture can be divided into 5 different segments in all directions.

3.3.2.2 Letter-box Format Detection

Letter-box format detection is included in order to automatically detect the horizontal black bars

used with letter-box input video (Cinemascope,...) signals. This detection system is based on a

proprietary algorithm that measures a certain level of data on a field basis.

This function can also detect video effects such as logos or subtitles inserted in the black parts of

the video. The programmer can use this data to create an automatic format conversion for all the

various cinema formats.

3.3.2.3 Format Conversion

The horizontal and vertical polyphase filters can be also used for the format conversions required

for adapting the input video to the display format. Various examples are shown in the following

figures. All formats are software-controlled and the letter-box format detector can also be used to

automatically select the best-suited display format to prevent the horizontal black bars from being

displayed.

Figure 10: Display Formats for 4:3 Input, 4:3 Aspect Ratio and 16:9 TV Screen

H compression 33%

H compression 16.5%

V expansion 16.5%

V expansion 33%

Non-linear H (Panoramic1)

Zoom 1

Zoom 2

Zoom 3

Zoom 5

No Zoom

STV3550 датащи(PDF) 26 Page - STMicroelectronics