Uncompressed 4K Research Articles

Experimental demonstration of uncompressed 4K video transmission over directly modulated distributed feedback laser‐based terahertz wireless link

AbstractWe demonstrate the transmission of uncompressed 4K videos over the photonics‐based terahertz (THz) wireless link using a directly modulated distributed feedback laser diode (DFB‐LD). For optical heterodyne mixing and data modulation, a DFB‐LD was employed and directly modulated with a 5.94‐Gb/s non‐return‐to‐zero signal, which is related to a 6G‐serial digital interface standard to support ultra‐high‐definition video resolution. We derived the optimal frequency of the THz carrier by varying the wavelength difference between DFB‐LD output and Tunable LD output in the THz signal transmitter to obtain the best transmission performances of the uncompressed 4K video signals. Furthermore, we exploited the negative laser‐to‐filter detuning for the adiabatic chirp management of the DFB‐LD by the intentional discrepancy between the center wavelength of the optical band‐pass filter and the output wavelength of the DFB‐LD. With the help of the abovementioned methods, we successfully transmitted uncompressed 4K video signals over the 2.3‐m wireless transmission distance without black frames induced by time synchronization error.

Perceptual Quality Assessment of HEVC and VVC Standards for 8K Video

With the growing data consumption of emerging video applications and users’ requirement for higher resolutions, up to 8K, a huge effort has been made in video compression technologies. Recently, versatile video coding (VVC) has been standardized by the moving picture expert group (MPEG), providing a significant improvement in compression performance over its predecessor high efficiency video coding (HEVC). In this paper, we provide a comparative subjective quality evaluation between VVC and HEVC standards for 8K resolution videos. In addition, we evaluate the perceived quality improvement offered by 8K over UHD 4K resolution. The compression performance of both VVC and HEVC standards has been conducted in random access (RA) coding configuration, using their respective reference software, VVC test model (VTM-11) and HEVC test model (HM-16.20). Objective measurements, using PSNR, MS-SSIM and VMAF metrics have shown that the bitrate gains offered by VVC over HEVC for 8K video content are around 31%, 26% and 35%, respectively. Subjectively, VVC offers an average of around 41% of bitrate reduction over HEVC for the same visual quality. A compression gain of 50% has been reached for some tested video sequences regarding a Student’s t-test analysis. In addition, for most tested scenes, a significant visual difference between uncompressed 4K and 8K has been noticed.

Design and PoC Implementation of Mmwave-Based Offloading-Enabled UAV Surveillance System

Among UAV applications, real-time high-resolution video surveillance systems using unmanned aerial vehicles (UAVs) especially gain our research interests, because high mobilities of UAVs and high qualities of videos can dramatically improve the surveillance performance and evolve the system, especially for artificial intelligence (AI)-based monitoring systems. However, it is challenging to transmit high-resolution videos to ground station in real-time and also impossible to perform AI detection based on these videos on UAVs. To address the challenges, we propose to take full advantages of mmWave communications and to apply it into UAV-based surveillance systems to transmit ultra-high-quality and ultra-high-resolution uncompressed 4K videos. To increase energy efficiency of UAVs, we propose to offload all computations via mmWave from UAVs to ground station. Moreover, in addition to design of system architecture, proof-of-concept (PoC) prototype hardware of the proposed system is practically developed to demonstrate technical feasibilities of mmWave communication on UAVs and the enhancements to practical surveillance applications. The practical issues in the implementation and the necessary hardware/software applied in the prototype system are explained in detail in this paper. An outdoor PoC experiment is conducted, and the experimental results are consistent with design, so that the effectiveness of the system is confirmed.

Terahertz topological photonics for on-chip communication

The computing speeds in modern multi-core processors and big data servers are no longer limited by the on-chip transistor density that doubles every two years following the Moores law, but are limited by the on-chip data communication between memories and microprocessor cores. Realization of integrated, low-cost, and efficient solutions for high speed, on-chip data communications require terahertz (THz) interconnect waveguides with tremendous significance in future THz technology including THz-wave integrated circuits and THz communication. However, conventional approaches to THz waveguiding suffer from sensitivity to defects and considerable bending losses at sharp bends. Here, building on the recently-discovered topological phase of light, we experimentally demonstrate robust THz topological valley transport on low-loss, all-silicon chips. We show that the valley polarized topological kink states exhibit unity transmission over a bulk band gap even after propagating through ten sharp corners. Such states are excellent information carriers due to their robustness, single-mode propagation, and linear dispersion-key properties for next generation THz communications. By leveraging the unique properties of kink states, we demonstrate error-free communication through a highly-twisted domain wall at an unprecedented data rate (10 Gbit/s) and uncompressed 4K high-definition video transmission. Our work provides the first experimental demonstration of the topological phases of THz wave, which could certainly inspire a plethora of research on different types of topological phases in two and three dimensions.

Efficient mode converter to deep-subwavelength region with photonic-crystal waveguide platform for terahertz applications.

Metallic deep-subwavelength features can aid in integration of microscopic components or strong light-matter interaction with a low-loss dielectric waveguide platform. A mode converter or coupler is required to integrate the devices. However, there is a vast difference in the physical scale and modal distribution between the deep-subwavelength structures and the dielectric waveguide platform. Here, we employ a tapered-slot mode converter to facilitate the electromagnetic wave transition from a gap width smaller than 1/100 of a wavelength (λ) to a larger-scale mode that is amenable to a terahertz (THz) silicon photonic-crystal waveguide. The mode converter is metallic, and fabricated on top of indium phosphide substrate, leading to incongruity with the modal field distribution of the silicon photonic-crystal waveguide. To mitigate this, a sandwiched structure is developed to match the symmetry of the mode of photonic-crystal waveguide, thereby facilitating efficient transfer of energy. For a proof of concept, we integrate a resonant tunneling diode (< 2 µm) as a THz detector in a photonic-crystal waveguide platform in the 0.3-THz band (λ ∼ 1 mm). The coupling efficiency is close to unity (∼90%) with broadband operation (∼50 GHz) in experiments. Thereafter, we employ the developed integrated device as a receiver in a THz communication experiment. In this manner, we successfully achieve real-time error-free data transmission at 32 Gbit/s, and demonstrate wireless transmission of uncompressed 4K high-definition video.

Light at the end of the fiber

light at the end of the fiber

Live Streaming of Uncompressed HD and 4K Videos Using Terahertz Wireless Links

Taming the Terahertz waves (100 GHz–10 THz) is considered the next frontier in wireless communications. While components for the ultra-high bandwidth Terahertz wireless communications were in rapid development over the past several years, however, their commercial availability is still lacking. Nevertheless, as we demonstrate in this paper, due to recent advances in the microwave and infrared photonics hardware, it is now possible to assemble a high-performance hybrid THz communication system for real-life applications. As an example, in this paper, we present the design and performance evaluation of the photonics-based Terahertz wireless communication system for the transmission of uncompressed 4K video feed that is built using all commercially available system components. In particular, two independent tunable lasers operating in the infrared C-band are used as a source for generating the Terahertz carrier wave using frequency difference generation in a photomixer. One of the IR laser beams carries the data which is intensity modulated using the LiNbO3 electro-optic modulator. A zero bias Schottky diode is used as the detector and demodulator of the data stream followed by the high-gain and low-noise pre-amplifier. The Terahertz carrier frequency is fixed at 138 GHz and the system is characterized by measuring the bit error rate for the pseudo random bit sequences at 5.5 Gbps. By optimizing the link geometry and decision parameters, an error-free ( $\text {BER} ) transmission at a link distance of 1 m is achieved. Finally, we detail the integration of a professional 4K camera into the THz communication link and demonstrate live streaming of the uncompressed HD and 4K video followed by the analysis of link quality.

4K Video over SMPTE 2022-5/6 Workflows

The next generation of live television is here! Unfortunately, the necessary bandwidth for ultrahigh-definition-television resolution video and higher frame rates for live uncompressed video transport is not. Uncompressed 4K video at 60 frames/s 4:2:2 requires 12 Gbits/s and even more for 4:4:4, which causes a problem for video transport across 10 Gbit/s Ethernet networks. “Lightly compressed” 4K is needed to fit in a single 10 Gbit Ethernet (GbE) cable. For the industry's existing and deployed infrastructure, the compression has to be capable of leveraging the already deployed SMPTE ST 2022-5/6 equipment. 1,2 Visually lossless compression for a single 4K stream over a 10 GbE link is also ideal. This paper explores the issues described and suggests the technologies required to fix the problem.

지상파 4K UHD 스포츠 라이브 중계방송

최근 몇 년간 차세대 방송으로 일컬어지는 UHD (Ultra High Definition) 방송 기술에 대한 많은 연구 및 개발이 진행되고 있다. 사람들의 이목이 집중되는 큰 스포츠 이벤트는 새로운 방송 기술을 홍보하기 위해 좋은 기회인만큼, KBS에서는 2014년에 있었던 세 번의 큰 스포츠 이벤트인 KBL (Korean Basketball League) 프로농구 결승전, 2014 브라질 월드컵, 2014 인천 아시안게임에 대해 4K 라이브 중계방송을 실시하였다. 특별히 KBL 프로농구 결승전은 세계 최초 지상파 4K 라이브 중계방송이었으며, 월드컵과 아시안게임에 대해서는 UHDTV를 보유한 시청자들이 각자의 집에서 UHD 방송을 즐길 수 있었다. 본 논문에서는 세 번의 스포츠 이벤트에 대한 전체적인 제작 및 전송과정에 대해 정리하였다. 특별히 경기 현장에서의 방송 제작, 실시간 HEVC 인코딩, SFN 전송, 국가과학기술연구망인 KREONOET을 통한 4K 무압축 영상에 대한 IP 전송 등에 대해 설명하였다. UHD (Ultra High Definition) has been developed and standardized over the past few years and considered as a key of the next generation broadcasting. Since major sporting events that attract many viewers have been good opportunities for applying and promoting new broadcasting technology, KBS (Korean Broadcasting System) has carried out live 4K terrestrial broadcasting of three big sports events in 2014, the KBL (Korean Basketball League) finals, the 2014 FIFA World Cup, and the 2014 Incheon Asian Games. Especially, 4K UHD live coverage of the KBL finals was the world's first live 4K terrestrial broadcasting, and people could enjoy the World Cup and the Asian Games with UHDTV at home. In this paper, the overall live production and data transmission of the sporting events is described, including on-location live production, live HEVC (High Efficiency Video Coding) encoding, SFN (Single Frequency Network) transmission, as well as experimental IP transmission of uncompressed 4K video via KREONET, a national R&D network run by KISTI (Korea Institute of Science and Technology Information).

Real-time long-distance transfer of uncompressed 4K video for remote collaboration

Better-than-high-definition-resolution video content (such as 4K) is already being used in some areas, such as scientific visualization and film post-production. Effective collaboration in these areas requires real-time transfers of such video content. Two of the main technical issues are high-data volume and time synchronization when transferring over an asynchronous network such as the current Internet. In this article, we discuss design options for a real-time long-distance uncompressed 4K video transfer system. We present our practical experience with such transfers and show how they can be used to increase productivity in film post-production, as an application example.

Real time switching and streaming transmission of uncompressed 4K motion pictures

In this paper we describe the world’s first Trans-Pacific and Trans-Atlantic real-time switching and streaming transmission of uncompressed 4K motion pictures. This demonstration, of an advanced networked media application, conveyed the 23rd Kyoto Prize events, held on Nov. 10 and 11, 2007, from Kyoto, Japan to Stockholm, Sweden in real-time with life-like image quality. Multiple live 4K streams from different cameras were switched over the network into a single uncompressed stream at the director’s request, and transmitted to Stockholm via 10 Gbit Ethernet connections over 21,000 km using the Global Lambda Integrated Facility (GLIF). We introduce several new technologies, including an uncompressed 4K video streaming system using Internet Protocol (IP) transmission and a shared line approach to gap-less video switching control. The Kyoto Prize 2007 demonstration proves the feasibility of using the IP infrastructure for next generation video switching and distribution networks, even at very high speeds across great distances.