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JPEG2K_E JPEG 2000 Encoder Core

Description | Symbol | Features | Applications | Block Diagram | Functional Description | Implementation Results | Support | Verification | Deliverables

The JPEG2K_E core is a high-performance image compression coprocessor that implements the computationally intensive part of the ISO/IEC 15444-1 JPEG2000 image compression standard.

The core supports lossless compression of 8 up to 12-bit component data, and lossy compression of component data up to 14 bits. The JPEG2K_E processing rate is on the order of 10 Mpixels/sec in lossless mode, and at significantly higher rates when used in lossy mode. A single or multiple instantiations of this core, along with a minimal amount of software on the user’s host processor, provides a complete high performance JPEG2000 image compression solution.

The wavelet engine supports both 5/3 and 9/7 filtering, while the entropy-coding engine supports all the key features of the JPEG2000 standard.

Additionally, the JPEG2K_E provides flexible interfaces and support a wide variety of pixel and component formats.

Symbol

Features

• ISO /IEC 15444-1 JPEG 2000 Image Coding System compliance
  • Support for both lossless and lossy compression
  • Support for error-resilient compression
  • Enables precise target rate control
• Flexible Input Image Format:
  • Sub-sampling factors up to 4 for each component
  • Tile size up to 256x256 (A different maximum tile size can be configured during synthesis)
• Programmable JPEG2000 options:
  • 2D-DWT filter type (5/3 or 9/7)
  • Number of 2D-DWT levels
  • Quantization tables
  • Entropy-coding switches (reset, restart, causal, segmark)
  • Input format (pixel depth, image/tile size, number of components, sub-sampling factors)
  • Code-block size (64x64 or 32x32)
  • Generation of distortion metrics and truncation lengths
• Tuneable architecture during synthesis:
  • Configurable 2D-DWT filter type (5/3 or 9/7 or both)
  • Configurable 2D-DWT data-path accuracy
  • Configurable number of Entropy Coding Units
  • Configurable maximum image/tile size
• Flexible Interfaces
  • 16-bit synchronous SRAM-style host interface
  • Polling registers and/or interrupt generation
  • Pixel can be fed either through the separate pixel interface or through the host interface
• Fully synchronous design

Applications

The JPEG2K_E can be utilized in a variety of multimedia applications including:

• Digital still cameras
• Networked video and image distribution systems
• Wireless video and image distribution systems
• Digital CCTV and surveillance systems
• Image/Video editing systems
• SDTV

Block Diagram

Functional Description

The JPEG2K_E operates on a rectangular section of an im-age called a tile. The maximum supported tile size depends on the number of components in the tile and the correspond-ing sub-sampling factors, which in turn define the size of the external tile memory. Originally, the core supports 3-component tiles with a maximum tile size of 160 x 128, and single-component tiles with a maximum tile size of 256 x 256. However, a different maximum tile size can be configured during synthesis.

The core provides a stream of attributes for each code-block. The code-block attributes can be used by the host’s software to create packet headers for the final JPEG2000 bit-stream. The core can be programmed so that it generates distortion metrics and truncation lengths for each coding pass. To pre-cisely control the JPEG2000 bit-stream size, the host can use the distortion metrics and the truncation lengths provided by the core.

The encode process consists of four basic steps: (1) load configuration and operating parameters; (2) load a single un-compressed tile into the JPEG2K_E; (3) wait for output data to become ready; and (4) unload compressed code-blocks and attributes.

In terms of internal operation, the input pixels are first level-shifted and then transformed using either the reversible 5/3 or the irreversible 9/7 two-dimensional discrete wavelet trans-form; the transformed coefficients are stored in the Tile Memory. After an entire tile has been transformed, the trans-formed coefficients are quantized; the quantized coefficients are stored code-block per code-block in the Code-Block Memory for entropy coding. The Entropy Coding Engines process the code-blocks stored in Code-Block Memory and store their output (compressed stream and attributes) in the output FIFOs.

Implementation Results

JPEG2K_E reference designs have been evaluated in a variety of technologies. The following are sample ASIC results using a 0.25 μm technology. Here the Slow architecture uses one entropy coding unit; Standard and Fast each use three.

Support

The core as delivered is warranted against defects for three years from purchase. Thirty days of phone and email technical support are included, starting with the first interaction. Additional maintenance and support options are available.

Verification

The core has been verified through extensive simulation and rigorous code coverage measurements. The SDF model of the core has been fed with a number of images that have been efficiently decoded by the standard’s reference software and the Kakadu software.

Deliverables

The core is available in ASIC (synthesizable HDL) and FPGA (netlist) forms, and includes everything required for successful implementation:

• HDL RTL source code (ASICs) or post-synthesis EDIF netlist (FPGAs)
• Sophisticated HDL Testbench including external FIFOs, buffers, models of interfaces, and the core
• Simulation script, vectors, expected results, and comparison utility
• Synthesis script (ASICs) or place and route script (FPGAs)
• Comprehensive user documentation, including detailed specifications and a system integration guide