JPEG XS (standardized as ISO/IEC 21122) is an interoperable, visually lossless, low-latency and lightweight image and video coding system used in professional applications.
Three main features are key to JPEG XS: Relying on these key features, JPEG XS is suitable for any application where uncompressed content is the norm, yet still allowing for significant savings in the required bandwidth usage, preserving quality and low latency.
In addition, the investments to upgrade the capacity of links and channels are significant and need to be amortized over several years.
Given the available bandwidth and infrastructure cost, relying on uncompressed video is therefore no longer an option, as 4K, 8K, increased bit depths (for HDR), and higher framerates need to be supported.
As stated, JPEG XS has built-in support for the direct compression of RAW Bayer/CFA images using the Star-Tetrix Color Transform.
[15] This means that the total amount of samples to further process and compress remains the same, yet the values are decorrelated similarly to a classical Multiple Component Transform.
This is advantageous because it allows to defer demosaicing the Bayer content from the moment of capturing to the production phase, where choices regarding artistic intent and various settings can be better made.
The ability to push this step out of the camera is possible with JPEG XS and allows to use more advanced algorithms resulting in better quality in the end.
The definition of profiles, levels, and sublevels allows for reducing the complexity of implementations in particular application use cases, while also safeguarding interoperability.
In addition, levels and sublevels provide limits to the maximum throughput in respectively the encoded (codestream) and the decoded (spatial and pixels) image domains.
Part 4 (ISO/IEC 21122-4) is a supporting standard of JPEG XS that provides conformance testing and buffer model verification.
In addition, the recommendation also registers the official Media Type Registration for JPEG XS video as video/jxsv, along with its mapping of all parameters into the Session Description Protocol (SDP).
ISO/IEC 13818-1:2022, known as MPEG-TS 8th edition, specifies carriage support for JPEG XS in MPEG Transport Streams.
Internet Protocol Media Experience (IPMX) is a suite of open standards and specifications to enable the carriage of compressed and uncompressed video, audio, and data over IP networks for the pro AV market.
While the standard[27] defines JPEG XS based on a hypothetical reference coder, JPEG XS is easier to explain through the steps a typical encoder performs:[28] Component up-scaling and optional component decorrelation: In the first step, the DC gain of the input data is removed and it is upscaled to a bit-precision of 20 bits.
Prequantization: The output of the wavelet filter is converted to a sign-magnitude representation and pre-quantized by a dead zone quantizer to 16-bit precision.
Thus sensor resolutions should be divided by four to calculate the respective width, height and amount of sampling grid points.
Similarly to the concept of levels, JPEG XS defines sublevels to represent a lower bound on the required throughput that conforming decoders need to support in the encoded image domain.
This license pool covers essential patents owned by Licensors for implementing the ISO/IEC 21122 JPEG XS video coding standard and is available under RAND terms.