Samsung S5PC100, User Manual

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S5PC100 USER’S MANUAL (REV1.0) JPEG
9.4-11
Table 9.4- 4. Markers in JPEG Codec
Marker Codes (hex) Description
SOI FFD8 Start of image
SOF
0
FFC0 Baseline JPEG
SOS FFDA Start of scan
DQT FFDB Define quantization table
DHT FFC4 Define Huffman table
DRI FFDD Define restart interval
RSTm FFD0~FFD7 Restart with module 8 count “m”
EOI FFD9 End of image
The markers in Talbe 9.4-4 are subject to process during decompression. The other markers except SOF1~SOFF
and JPG are ignored.
5.10 BITSTREAM OF COMPRESSED FILE
The created JPEG bit stream is shown below. In the figure, ECS is an acronym of ‘entropy-coded segment’ which
is a sequence of entropy coded bytes.
SOI DQT DRI SOF0 DHT SOS ECS EOI
Figure 9.4- 7 Bitstream of Compressed File
5.11 JPEG COMPRESSION FLOW
This is a pseudo instruction set that indicates the write or read on specific registers. It is assumed that the
Huffman and quantization tables were written already.
// JPEG encoder initialization
Write JPGCMOD 0x21 // Mode selection and core clock setting
Write JPGMOD 0x1 // Encoding and YCbCr4:2:2
Write JPGDRI 0x0 // No DRI if 0. Set an appropriate value.
Write QHTBL 0x0 // Choose the appropriate table index for Huffman & Quantization tables.
Write JPGY 0x40 // Vertical resolution
Write JPGX 0x40 // Horizontal resolution
Write IMGADR 0x1000_0000 // Address for an image to compress
Write JPGADR 0x1001_0000 // Address for the compressed JPEG file