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ZR36016

INTEGRATED COLOR SPACE / RASTER-TO-BLOCK CONVERTER

Zoran Corporation 

ZR36016

PRELMINARY INTEGRATED COLOR SPACE / RASTER-TO-BLOCK CONVERTER

FEATURES

s Raster-to-block and block-to-raster conversions with strip

buffer of external SRAMs.

s Color space conversions of RGB to/from YCbCr or YeMaCy.

s Supports Fast Preview expansion and Lossless Compres-

sion/Expansion modes of the ZR36050.

s Exclusive dual pixel buses. Separate format and color space

conversions on the ZR36050 data and output data during

compression and expansion.

s Supports 4:4:4, 4:4:4:4, 4:2:2, 4:1:1 and 1:0:0 I/O formats.

s Supports many format conversions between pixel input bus

and pixel output bus, pixel input bus and ZR36050, and

ZR36050 and pixel output bus.

s Supports filtering for image format conversions.

s Horizontal decimation/interpolation with optional filtering and

vertical decimation/interpolation by line dropping or

replication.

s Enable function of pixel I/O buses for asynchronous

applications.

s Sequential processing mode simplifies motion JPEG

implementation.

s Provides windowing function to select processing area.

s TTL levels for Input/Output.

s 160 pin PQFP.

DESCRIPTION

The ZR36016 is a pre- and post-processor for use with a

ZR36050 JPEG Image Codec, performing raster-to-block reor-

dering and color space conversion.

The ZR36016 accepts input pixels in a variety of common color

spaces. The pixel data can undergo format and color space con-

version, with converted data available on the pixel output bus

(Figure 1). When compressing, the data fed to the ZR36050 can

be cropped within a selected window area, and its format can be

different from that of the pixel output bus. For instance, it is

possible to output an RGB(4:4:4) input onto the pixel output bus

and to feed the ZR36050 with a YbCr(4:2:2) format. It is also

possible to output a YCbCr(4:2:2) format input as RGB(4:4:4)

and to feed the ZR36050 with a YCbCr(4:1:1) format. During

expansion, for instance, the ZR36016 can output an RGB(4:4:4)

input directly onto the output pixel bus, and after converting YCb-

Cr(4:2:2) format coming from the ZR36050 into RGB(4:4:4), it

overlays it in a window on the pixel input data.

The ZR36016 uses an external SRAM double-strip buffer for

raster-block conversions and block interleaving. The Fast

Preview and Lossless modes of operation of the ZR36050 are

also supported, in which case the SRAM is used only for raster-

to-raster buffering and pixel interleaving. Depending on the

SRAM size and the mode of operation, the maximum line length

can be up to 64K pixels. The number of lines per image can be

up to 64K.

Processing of data on the pixel buses can be continuous as

required for live frame capture or Motion JPEG, or it can be dis-

continuous, with pixels transferred only when enabled by an

enable signal.

The data transfer rate with the ZR36050 is at a maximum of

30 MHz, the system clock rate. The pixel buses transfer at a

maximum of 30 MHz for 4:0:0, or at a frequency ratio of 1, 1/2 or

1/4 of the system clock for the other formats, depending on the

format conversions that are selected.

As shown in Figure 2, the input pixel data pass through a multi-

plexer, to the color space convertor. In compression, this

multiplexer always passes the pixel data (the top input). The

output of the color space convertor takes two paths in compres-

sion, one to the pixel output bus and the other to the raster to

block convertor. The data on each path can independently

undergo format conversion, which in this context means a reso-

lution transformation by decimation or interpolation, of the

chrominance components; for example, decimation from

PXIN

Color Space Conversion

Format Conversion

Window Management

Raster-to-Block

ZR36050

Compression

PXOUT

PXIN

Color Space Conversion

Format Conversion

Window Management

Block-to-Raster

ZR36050

Expansion

Figure 1. ZR36016 Operations with a ZR36050

PXOUT

ZORAN Corporation s 1705 Wyatt Drive s Santa Clara, CA 95054 s (408) 986-1314 s FAX (408) 986-1240

This document was created with FrameMaker 4.0.4

July 1995

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