ADV212 AD [Analog Devices], ADV212 Datasheet - Page 25

• Manufacturer Part Number: ADV212
• Description: JPEG 2000 Video Codec
• Manufacturer: AD [Analog Devices]

THEORY OF OPERATION
The input video or pixel data is passed on to the ADV212’s pixel
interface, and samples are deinterleaved and passed on to the
wavelet engine, which decomposes each tile or frame into
subbands using the 5/3 or 9/7 filters. The resultant wavelet
coefficients are then written to the internal memory. The
entropy codecs code the image data so that it conforms to the
JPEG 2000 standard. An internal DMA provides high
bandwidth memory-to-memory transfers, as well as high
performance transfers between functional blocks and memory.
WAVELET ENGINE
The ADV212 provides a dedicated wavelet transform processor
based on the Analog Devices proven and patented SURF
technology. This processor can perform up to six wavelet
decomposition levels on a tile. In encode mode, the wavelet
transform processor takes in uncompressed samples, performs
the wavelet transform and quantization, and writes the wavelet
coefficients in all frequency subbands to the internal memory.
Each of these subbands is further broken down into code
blocks. The code-block dimensions can be user defined and are
used by the wavelet transform processor to organize the wavelet
coefficients into code blocks when writing to the internal
memory. Each completed code block is then entropy coded by
one of the entropy codecs.
In decode mode, wavelet coefficients are read from internal
memory and recomposed into uncompressed samples.
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ENTROPY CODECS
The entropy codec block performs context modeling and
arithmetic coding on a code block of the wavelet coefficients.
Additionally, this block also performs the distortion metric
calculations during compression that are required for optimal
rate and distortion performance. Because the entropy coding
process is the most computationally intensive operation in the
JPEG 2000 compression process, three dedicated hardware
entropy codecs are provided on the ADV212.
EMBEDDED PROCESSOR SYSTEM
The ADV212 incorporates an embedded 32-bit RISC processor.
This processor is used for configuration, control, and manage-
ment of the dedicated hardware functions, as well as for parsing
and generation of the JPEG 2000 code stream. The processor
system includes memory for both the program and data
memory, the interrupt controller, the standard bus interfaces,
and other hardware functions such as timers and counters.
MEMORY SYSTEM
The main function of the memory system is to manage wavelet
coefficient data, interim code-block attribute data, and
temporary workspace for creating, parsing, and storing the
JPEG 2000 code stream. The memory system can also be used
for the program and data memory for the embedded processor.
INTERNAL DMA ENGINE
The internal DMA engine provides high bandwidth memory-
to-memory transfers, as well as high performance transfers
between memory and functional blocks. This function is critical
for high speed generation and parsing of the code stream.
ADV212