Saturday, May 18, 2024

MPEG news: a report from the 146th meeting

 This blog post is based on the MPEG press release and has been modified/updated here to focus on and highlight research aspects. This version of the blog post will also be posted at ACM SIGMM Records.

The 146th MPEG meeting was held in Rennes, France from 22-26 April 2024, and the official press release can be found here. It comprises the following highlights:
  • AI-based Point Cloud Coding*: Call for proposals focusing on AI-driven point cloud encoding for applications such as immersive experiences and autonomous driving.
  • Object Wave Compression*: Call for interest in object wave compression for enhancing computer holography transmission.
  • Open Font Format: Committee Draft of the fifth edition, overcoming previous limitations like the 64K glyph encoding constraint.
  • Scene Description: Ratified second edition, integrating immersive media objects and extending support for various data types.
  • MPEG Immersive Video (MIV): New features in the second edition, enhancing the compression of immersive video content.
  • Video Coding Standards: New editions of AVC, HEVC, and Video CICP, incorporating additional SEI messages and extended multiview profiles.
  • Machine-Optimized Video Compression*: Advancement in optimizing video encoders for machine analysis.
  • MPEG-I Immersive Audio*: Reached Committee Draft stage, supporting high-quality, real-time interactive audio rendering for VR/AR/MR.
  • Video-based Dynamic Mesh Coding (V-DMC)*: Committee Draft status for efficiently storing and transmitting dynamic 3D content.
  • LiDAR Coding*: Enhanced efficiency and responsiveness in LiDAR data processing with the new standard reaching Committee Draft status.
* ... covered in this column.

AI-based Point Cloud Coding

MPEG issued a Call for Proposals (CfP) on AI-based point cloud coding technologies as a result from ongoing explorations regarding use cases, requirements, and the capabilities of AI-driven point cloud encoding, particularly for dynamic point clouds.

With recent significant progress in AI-based point cloud compression technologies, MPEG is keen on studying and adopting AI methodologies. MPEG is specifically looking for learning-based codecs capable of handling a broad spectrum of dynamic point clouds, which are crucial for applications ranging from immersive experiences to autonomous driving and navigation. As the field evolves rapidly, MPEG expects to receive multiple innovative proposals. These may include a unified codec, capable of addressing multiple types of point clouds, or specialized codecs tailored to meet specific requirements, contingent upon demonstrating clear advantages. MPEG has therefore publicly called for submissions of AI-based point cloud codecs, aimed at deepening the understanding of the various options available and their respective impacts. Submissions that meet the requirements outlined in the call will be invited to provide source code for further analysis, potentially laying the groundwork for a new standard in AI-based point cloud coding. MPEG welcomes all relevant contributions and looks forward to evaluating the responses.

Research aspects: In-depth analysis of algorithms, techniques, and methodologies, including a comparative study of various AI-driven point cloud compression techniques to identify the most effective approaches. Other aspects include creating or improving learning-based codecs that can handle dynamic point clouds as well as metrics for evaluating the performance of these codecs in terms of compression efficiency, reconstruction quality, computational complexity, and scalability. Finally, the assessment of how improved point cloud compression can enhance user experiences would be worthwhile to consider here also.

Object Wave Compression

A Call for Interest (CfI) in object wave compression has been issued by MPEG. Computer holography, a 3D display technology, utilizes a digital fringe pattern called a computer-generated hologram (CGH) to reconstruct 3D images from input 3D models. Holographic near-eye displays (HNEDs) reduce the need for extensive pixel counts due to their wearable design, positioning the display near the eye. This positions HNEDs as frontrunners for the early commercialization of computer holography, with significant research underway for product development. Innovative approaches facilitate the transmission of object wave data, crucial for CGH calculations, over networks. Object wave transmission offers several advantages, including independent treatment from playback device optics, lower computational complexity, and compatibility with video coding technology. These advancements open doors for diverse applications, ranging from entertainment experiences to real- time two-way spatial transmissions, revolutionizing fields such as remote surgery and virtual collaboration. As MPEG explores object wave compression for computer holography transmission, a Call for Interest seeks contributions to address market needs in this field.

Research aspects: Apart from compression efficiency, lower computation complexity, and compatibility with video coding technology, there is a range of research aspects, including the design, implementation, and evaluation of coding algorithms within the scope of this CfI. The QoE of computer-generated holograms (CGHs) together with holographic near-eye displays (HNEDs) is yet another dimension to be explored.

Machine-Optimized Video Compression

MPEG started working on a technical report regarding to the "Optimization of Encoders and Receiving Systems for Machine Analysis of Coded Video Content". In recent years, the efficacy of machine learning-based algorithms in video content analysis has steadily improved. However, an encoder designed for human consumption does not always produce compressed video conducive to effective machine analysis. This challenge lies not in the compression standard but in optimizing the encoder or receiving system. The forthcoming technical report addresses this gap by showcasing technologies and methods that optimize encoders or receiving systems to enhance machine analysis performance.

Research aspects: Video (and audio) coding for machines has been recently addressed by MPEG Video and Audio working groups, respectively. MPEG Joint Video Experts Team with ITU-T SG16, also known as JVET, joined this space with a technical report, but research aspects remain unchanged, i.e., coding efficiency, metrics, and quality aspects for machine analysis of compressed/coded video content.

MPEG-I Immersive Audio

MPEG Audio Coding enters the "immersive space" with MPEG-I immersive audio and its corresponding reference software. The MPEG-I immersive audio standard sets a new benchmark for compact and lifelike audio representation in virtual and physical spaces, catering to Virtual, Augmented, and Mixed Reality (VR/AR/MR) applications. By enabling high-quality, real-time interactive rendering of audio content with six degrees of freedom (6DoF), users can experience immersion, freely exploring 3D environments while enjoying dynamic audio. Designed in accordance with MPEG's rigorous standards, MPEG-I immersive audio ensures efficient distribution across bandwidth-constrained networks without compromising on quality. Unlike proprietary frameworks, this standard prioritizes interoperability, stability, and versatility, supporting both streaming and downloadable content while seamlessly integrating with MPEG-H 3D audio compression. MPEG-I's comprehensive modeling of real-world acoustic effects, including sound source properties and environmental characteristics, guarantees an authentic auditory experience. Moreover, its efficient rendering algorithms balance computational complexity with accuracy, empowering users to finely tune scene characteristics for desired outcomes.

Research aspects: Evaluating QoE of MPEG-I immersive audio-enabled environments as well as the efficient audio distribution across bandwidth-constrained networks without compromising on audio quality are two important research aspects to be addressed by the research community.

Video-based Dynamic Mesh Coding (V-DMC)

Video-based Dynamic Mesh Compression (V-DMC) represents a significant advancement in 3D content compression, catering to the ever-increasing complexity of dynamic meshes used across various applications, including real-time communications, storage, free-viewpoint video, augmented reality (AR), and virtual reality (VR). The standard addresses the challenges associated with dynamic meshes that exhibit time-varying connectivity and attribute maps, which were not sufficiently supported by previous standards. Video-based Dynamic Mesh Compression promises to revolutionize how dynamic 3D content is stored and transmitted, allowing more efficient and realistic interactions with 3D content globally.

Research aspects: V-DMC aims to allow "more efficient and realistic interactions with 3D content", which are subject to research, i.e., compression efficiency vs. QoE in constrained networked environments.

Low Latency, Low Complexity LiDAR Coding

Low Latency, Low Complexity LiDAR Coding underscores MPEG's commitment to advancing coding technologies required by modern LiDAR applications across diverse sectors. The new standard addresses critical needs in the processing and compression of LiDAR-acquired point clouds, which are integral to applications ranging from automated driving to smart city management. It provides an optimized solution for scenarios requiring high efficiency in both compression and real-time delivery, responding to the increasingly complex demands of LiDAR data handling. LiDAR technology has become essential for various applications that require detailed environmental scanning, from autonomous vehicles navigating roads to robots mapping indoor spaces. The Low Latency, Low Complexity LiDAR Coding standard will facilitate a new level of efficiency and responsiveness in LiDAR data processing, which is critical for the real-time decision-making capabilities needed in these applications. This standard builds on comprehensive analysis and industry feedback to address specific challenges such as noise reduction, temporal data redundancy, and the need for region-based quality of compression. The standard also emphasizes the importance of low latency coding to support real-time applications, essential for operational safety and efficiency in dynamic environments.

Research aspects: This standard effectively tackles the challenge of balancing high compression efficiency with real-time capabilities, addressing these often conflicting goals. Researchers may carefully consider these aspects and make meaningful contributions.

The 147th MPEG meeting will be held in Sapporo, Japan, from July 15-19, 2024. Click here for more information about MPEG meetings and their developments.

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