Presentation Transcript
About JPEG2000 :About JPEG2000 New image coding system based on wavelet technology
In 2004, it was selected as the mandatory compression format for Digital Cinema
Slide 3:License-free
Improved Compression Efficiency
Mathematically Lossless Compression
Graceful Degradation
Scalability
Dynamic Bandwidth Allocation
Robust Transmission
Easy Post-Production
Region of Interest (ROI)
Low Latency
Constant Quality through Multiple Generations
Encoding - Decoding Processing Power
Open Standard
Slide 4:License-Free
The JPEG committee has stated:
“Standards should be implementable without payment of royalty and license fees”
“Agreements have been reached with over 20 large organizations to allow use of their IP without payment of license fees or royalties”
Improved Compression Efficiency :Improved Compression Efficiency
Mathematically Lossless Compression :Mathematically Lossless Compression It enables a reduction in storage requirement of, on average, 1:2 while still being able to recover the exact original image information.
Extremely important feature in fields such as digital archiving, cinema acquisition and medical imaging.
Unique advantage in comparison to JPEG, MPEG2, MPEG4
Graceful Degradation :Graceful Degradation In JPEG 2000 the effect of image compression is a soft blur on high-frequency areas Image compressed with JPEG 2000 with a compression ratio of 400:1 Image compressed with JPEG 2000 with a 2:1 compression ratio
Scalability :Scalability JPEG 2000 is able to extract multiple versions out of a single compressed file This scalability provides
Easy proxy generation
Region of Interest
Bandwidth optimization and adaptative transmission
Slide 9:Example of a Progression in Quality
Dynamic Bandwidth Allocation :JPEG 2000 scalability over highly variable channels (over-IP or Wireless) provides a powerful dynamic quality allocation.
Giving priority to fundamental data packets allows ‘best achievable quality’ for the available bandwidth
Increasing redundancy of fundamental data packets also guarantees a minimum image quality for weak signals Dynamic Bandwidth Allocation
Robust Transmission :Robust Transmission JPEG 2000 intrinsic robustness prevents having dramatic visual impact when packets are missing or corrupted
JPEG 2000 intra-frame nature gives another advantage to long-GOP formats: it limits the impact of the missing or corrupt packet to a single frame
Easy Post-Production :Easy Post-Production Easy-Proxy
From a single file editors can extract a proxy and use full resolution image for the rendering chain
Easy Editing
Intra-frame coding enables editors to easily access each frame
Region Of Interest (ROI) :Region Of Interest (ROI) JPEG 2000 is also able to prioritize a user defined area of the image, to which it will provide the full quality layer
Low Latency :Low Latency Intra-frame allows every frame to be encoded independently allowing latency of less than 1 frame In comparison, inter-frame encoding formats (e.g. MPEG2, MPEG4) need to work with Groups of Pictures (GOP) that require a longer processing time…….
Low latency is a critical consideration in many applications………………..
Constant Quality Through Multiple Generations :Successive encoding-decoding passes are usually required throughout the Broadcast and Digital Cinema post-production processing chain
JPEG 2000 provides a constant image quality throughout the production process Constant Quality Through Multiple Generations
Processing Power :Processing Power JPEG 2000 is a symmetrical compression technology requiring approximately the same processing power to encode or to decode at any compression quality
The JPEG 2000 standard supports every resolution, color depth, number of components and frame rate
It is the image compression format most ready to address future applications Open Standard
Slide 18:Pre-Processing
Wavelet Transform
Compression
Rate Control
Data Ordering
Pre-Processing :Pre-Processing The pre-processing block mainly deals with color conversion (or decorrelation):
RGB ? YCbCr (Irreversible Color Transform)
RGB ? YUV (Reversible Color Transform)
The Discrete Wavelet Transform :The Discrete Wavelet Transform Components are passed recursively through low and high pass Wavelet filters
This enables an intra-component de-correlation that concentrates the image information in a small and very localized area and multi-resolution image representation
Slide 22:How Wavelet Decomposition Achieves Multi-Resolution
Compression of the Wavelet Coefficients :Compression of the Wavelet Coefficients By itself the Wavelet Transform does not compress image data; it restructures the image information so that it is easier to compress
Once the Discrete Wavelet Transform (DWT) has been applied, the output is quantized. The quantized data is then encoded in the Entropy Coding Unit (ECU)
Rate Control :Rate Control Given a targeted bit-rate, the Rate-Control module adjusts the coding precision of each pixel (small groups of pixels called code-blocks)
It embeds all groups of pixels in a succession of Packets. These Packets, along with additional headers, form the final JPEG 2000 code-stream
In the last ‘data ordering’ block the preferred scalability (or progression order) is selected Data Ordering
Codestream Syntax :Codestream Syntax
The Implementation :The Implementation intoPIX provides the most flexible and powerful range of JPEG 2000 implementations available
intoPIX efficient image processing allows implementation on a single FPGA
intoPIX technology currently addresses Digital Cinema and Broadcast markets.
Since 2004 intoPIX founders have been the editors of the reference open source code - openJPEG: www.openjpeg.org www.intopix.com