The LJPEG-D IP Core from Alma Technologies is a matching decoder for the Alma Technologies Lossless JPEG Encoder and supports up to 16-bit per component Numerically Lossless decoding. Coupled with the LJPEG-E, the decoder is ideal for image and video compression applications where bit-by-bit accurate reproduction of an image is essential, while the amount of compression needed is very low and the silicon resource usage is critical. The LJPEG-D is available for ASIC or AMD-Xilinx, Efinix, Intel, Lattice and Microsemi FPGA and SoC based designs.

The LJPEG-D is based on the spatial (sequential) lossless compression mode (SOF3) of the ISO/IEC 10918-1 JPEG standard. Rather than the Discrete Cosine Transform (DCT) functions used for lossy JPEG compression - which introduce round-off errors - Lossless JPEG employs a predictor function and compresses images by encoding the prediction error with no information loss.

The core is designed with simple, fully flow-controllable and FIFO-like, streaming input and output interfaces. Being carefully designed, rigorously verified and silicon-proven, the LJPEG-D is a compact, reliable and easy-to-use and integrate IP.

IP Deliverables

Clear text VHDL or Verilog RTL source for ASIC designs, or pre-synthesized and verified Netlist for FPGA and SoC devices

Release Notes, Design Specification and Integration Manual documents

Bit Accurate Model (BAM) and test vector generation binaries, including sample scripts

Self checking testbench environment, including sample BAM generated test cases

Simulation and sample Synthesis (for ASICs) or Place & Route (for FPGAs) scripts

Symbol

Features

ISO/IEC 10918-1 (Annex H) Compliant Lossless JPEG Decoder

Up to 64K x 64K image resolution

1, 2 or 3 (4:4:4 only) image components

2-16 bit per image component

Up to 4 stream programmable Huffman Tables

Stream programmable Restart Interval

Stream programmable Point Transform function

Limitations with Respect to the ISO/IEC 10918-1 Standard

Up to 3 image components are supported
(Nf field of the SOF3 marker segment = 1 or 2 or 3)

Single-scan
(Only one SOS marker segment, with Ns field = Nf)

The DNL marker is not supported
(Y field of the SOF3 marker segment > 0)

Fixed parameters

No sub-sampling
(Hi and Vi fields of the SOF3 marker segment = 1)

Prediction function is fixed to the left-hand predictor
(Ss field of SOS marker segment = 1)

Ease of Integration

Single clock cycle per decoded sample throughput

Simple, microcontroller like, programming interface

High-speed, flow controllable, streaming I/O data interfaces

Simple and FIFO like

Avalon-ST compliant (ready latency 0)

AXI4-Stream compliant

CPU-less, standalone operation

Trouble-Free Technology Map and Implementation

Fully portable, self-contained RTL source code

Strictly positive edge triggered design

D-type only Flip-Flops

Fully synchronous operation

No special timing constraints required

No false paths

No multi-cycle paths

Literature

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