Specifications

CORE LOGIC Proprietary and Confidential
45
www.corelogic.co.kr │
4.6. JPEG ENCODING
4.6.1. Still JPEG Encoding
Perform JPEG encoding by converting the image entered from Camera to the
various sizes. Camera image supports up to 3 Mega-Pixel(2048x1536). JPEG Codec
is JPEG Baseline method and supports Camera image of YCbCr 4:2:2 Format.
The capacity of the internal SRAM buffer is limited. Therefore JPEG file should be
read in use of Flow Control before the JPEG buffer which had been set while
decoding is over-flown.
JPEG Encoding is similar to Preview procedure. First, select the area encoded
from the original image entered from Camera and set JPEG Target resolution.
1. Select Source image by 4 pixel unit from the original image. In the register
setup of the CL765, StartX, StartY, Width and Height are selected from the
source image. Relative registers are 0x10, 0x11 and 0x9d.
2. Set Target image resolution by adjusting to JPEG Target. The resolution unit
of the target image is also 4-pixel. The relative registers are 0x14and 0x9d.
3. Set JPEG encoding at 0x00 command register.
4. Flow Control is used to prevent a buffer from overflow when the data size
exceeds the threshold of JPEG buffer, which had been already decided. Flow
Control is not necessary when file size is small because of slam JPEG Target
resolution. For more details, refer to the description in ‘Flow Control’ Part.
5. Completion of JPEG encoding. Interrupt is used to complete JPEG encoding.
For more details, refer to the description in ‘Interrupt’ Part.
6. JPEG File Read. To read JPEG file, two methods are used; to use Flow Control
and to read JPEG file after completing JPEG encoding. Fore more details on
JPEG file read, refer to the description in ‘SRAM Readʹ Part.