JPEG 2000 stream parser
This module analyses the headers, unpacks the compressed data and sends them to the entropy
decoding unit.
Entropy decoder (modeler and arithmetic decoder)
This module gets compressed coding passes from the parser and converts them to quantized code
blocks. The Modeler gives the sequencing of the entropy decoding: it reconstructs the code block bit
plane by bit plane from most significant to least significant and places relevant bits in zigzag order in
each bit plane. Moreover it computes the context information needed by the arithmetic decoder.
The contexts and the bit stream provided by the parser are processed by the Arithmetic Decoder that
generates the decoded bits placed at the right location by the Modeler.
Frame assembler
This unit reconstructs subbands based on the code blocks coming from the entropy decoding channels.
This is done by writing the decoded codeblocks into the external memory at the right location inside the
subband they belong to.
Inverse quantizer
The inverse quantizer applies an inverse quantization step as specified in the stream header. A different
inverse quantization step is available for each subband resulting in differently weighted frequency
subbands. The quantization steps are extracted from the JPEG 2000 file headers by the header parser.
2D IDWT
This module performs the inverse 2D wavelet transform. It is able to process frames without tiling (with
a size up to 4096x2160). It performs wavelet recomposition on the subbands situated in the off-chip tile
buffer with a programmable number of decomposition levels up to 6, as specified in the stream header.
Both 9/7 and 5/3 filters are supported.
ICT/RCT
If enabled, this unit performs the irreversible or reversible color transform on the samples generated by
the wavelet transform. This optional operation converts samples from YUV to RGB. It is used to improve
the compression efficiency. The ICT/RCT module generates reconstructed samples of any size up to 12
bits. The operation is activated by the header decoder.
Host interface
This interface provides status and command lines at the disposal of the user. These are used to trigger
decoding of JPEG 2000 DCI files and to follow the status of the decoding process. The user intervention
is minimized and the core has a completely autonomous behaviour.
Memory controller (option)
The JPEG 2000 decoding core uses external memory to store temporary intermediate data to ensure
smooth and efficient processing of the video stream. This is achieved by using DDR/DDR2 SDRAM. The
JPEG 2000 decoder IP core interfaces with the memory controller through an easy generic multi-port
interface allowing the user to implement his own memory controller and to adapt the decoding
architecture to the exact board topology. A dedicated memory controller can also be purchased
separately as an option to the BA109 IP core.
Page 3 of 4 - 31 March 2008
Technical specifications are subject to change without prior notice
