Gong Bo, Li Na, Wang Jingyu
Abstract: Focusing on the theme of “standards guiding innovation and quality supporting development,” this paper presents the recent exploratory efforts by the China Research Institute of Film Science & Technology (Film Technology and Quality Inspection Institute, Central Propaganda Department) in the field of domestic LED cinema projection technology. Through optical and acoustic performance assessments and data analysis conducted in theaters equipped with domestic LED projection systems, the paper summarizes the current key issues and observable phenomena within LED cinema environments. Based on these findings, the study offers recommendations for the initial application and long-term development of domestic LED cinema projection systems. The goal is to provide a foundation of standards, technical support, and strategic direction to drive innovation, manufacturing, and broader adoption of LED projection technologies made in China.|
Keywords: LED cinema; film technology standards; field research; LED sound-permeable screen
As an innovative form of digital cinema display technology, LED-based digital cinema projection offers significant optical advantages over traditional “projector + screen” systems. These advantages include higher brightness, enhanced contrast ratios, wider dynamic range, improved uniformity, and distortion-free images—features that deliver a powerful visual impact and a new level of cinematic experience for audiences. At the same time, LED projection enables new operational models for theaters and has emerged as a key global trend in the evolution of cinema projection technology.
Seizing this opportunity for technological upgrade, China has leveraged its strengths in LED display manufacturing, supply chain integration, and independent R&D capabilities in LED cinema projection systems. As of September 2024, a total of 13 domestic brands and 30 models of LED cinema projection systems have passed Digital Cinema Initiatives (DCI) certification, accounting for over 70% of the global share, with more than 40 auditoriums in China already equipped with domestic LED systems—signaling a promising outlook for industry-wide application and growth. The China Research Institute of Film Science & Technology (Film Technology and Quality Inspection Institute under the Central Propaganda Department, hereinafter referred to as the “China Film Research Institute”) is the only national-level scientific institution in China’s film industry. It bears the mission of advancing technological innovation and high-quality development of the sector. Since 2017, the institute has undertaken dedicated research on the application of LED display technology to cinema screens, aiming to overcome critical technological bottlenecks. As a result, major breakthroughs have been achieved in the field of domestic LED cinema projection. This LED-based digital cinema projection model represents a significant innovation and upgrade to the traditional projection-and-screen system. Recognizing the need for standards to guide and regulate this transformation, the China Film Research Institute released a national industry standard in 2023—DY/T 8-2023: Technical Requirements and Measurement Methods for Digital Cinema LED Auditoriums.
In August 2024, to evaluate how well the standard has been understood and implemented, and to promote the orderly development of LED auditoriums, the institute led a nationwide survey of 38 operating LED auditoriums. The research involved technical data collection, in-depth analysis, and summarization of the current challenges and phenomena observed in the field. Based on the findings, this paper presents targeted recommendations for both the early-stage application and the future evolution of domestic LED cinema projection systems—offering a technical roadmap and support framework for R&D, manufacturing, and industry deployment.
Film Technology Standards: Building a Foundation for Innovation
Film technology standards serve as a reliable foundation for technological innovation in the film industry. They ensure compatibility and interoperability of new technologies, enhance the effectiveness and quality of innovation outcomes, and promote overall technological advancement.
The China Research Institute of Film Science & Technology has consistently adhered to globally unified film technology standard systems and actively promotes major technological innovations in the film sector. Relying on standardized documents and technical specifications issued by organizations such as the International Organization for Standardization (ISO) and Digital Cinema Initiatives (DCI), the institute has partnered with domestic enterprises to independently develop China’s first 2K and 4K LED cinema projection systems. These systems have successfully passed DCI certification and have already been deployed internationally—allowing China to chart its own path and leapfrog into a leadership position in the development and application of next-generation cinema projection systems. To address the issue of inconsistent audio-visual alignment in non-acoustically transparent LED cinema screens, the China Film Research Institute spearheaded the development of the world’s first acoustically transparent LED cinema screen with fully independent intellectual property rights. This innovation, which has also passed DCI certification, fills a critical technical gap in both China and the global LED projection industry by enabling accurate sound reproduction from behind the screen—effectively solving the problem of sound-image mismatch in theaters and reducing acoustic interference caused by sound reflections from LED displays. The technology has now entered commercial application. Using the LED cinema technical standard as a foundation, the institute has also established a dedicated LED mastering environment and system. This integrates the advantages of LED display technology with high-tech cinema formats. Research efforts have focused on key technologies such as domestically developed digital LED projection, DCI-compliant HDR, China-native HDR, and immersive audio formats, resulting in the development of workflows and solutions for LED SDR and HDR digital cinema masters. Initial implementation of HDR mastering for LED display has been achieved, laying the groundwork for LED-native distribution formats and delivering an exclusive, cutting-edge visual experience for audiences. In addition to pioneering innovation in domestic LED cinema projection, efforts have also been made to reimagine the entire theatrical environment while remaining compliant with technical standards for digital cinema exhibition. Advanced technologies such as LED, immersive audio, and virtual reality (VR) have been employed to upgrade the spatial experience within theaters.
A prime example is the immersive LED cinema deployed in Hainan, where a 4K main screen is installed at the front of the auditorium, flanked by multiple side screens forming a 270° panoramic visual field. When combined with immersive sound technology, this configuration creates a truly enveloping viewing experience. This project represents a leading-edge exploration into the integrated, multi-service development of cinema environments.
Film Technology Standards: Strengthening the Assurance of Projection Quality
1. Development of Industry Standards
To ensure and improve the projection quality of LED cinema auditoriums and to promote their standardized and orderly development, the China Research Institute of Film Science & Technology took the lead in formulating the industry standard DY/T 8–2023: Technical Requirements and Measurement Methods for Digital Cinema LED Auditoriums.
This standard defines the optical performance parameters for both 2D and 3D LED cinema projection, as well as requirements for image viewing quality, architectural acoustics, and electroacoustic characteristics. It encompasses the traditional technical specifications used in conventional cinema projection, while also introducing enhanced parameters based on the unique advantages of LED systems—such as high dynamic range and exceptional brightness and chromaticity uniformity. Specifically, the standard introduces performance benchmarks for:
Full-screen brightness
Brightness uniformity at the module level
Chromaticity uniformity at the module level
HDR playback capability
These specifications serve as a technical foundation for equipment installation, system calibration, quality supervision, and technical management in LED auditoriums, helping to ensure a consistent and high-quality cinematic experience.
2. Findings from LED Cinema Projection Surveys
Table 1: Statistical Analysis of LED Cinema Theater Survey Data for Digital Cinema
| No. | Survey Parameter | Pass Rate | Fail Rate |
|---|---|---|---|
| 1 | Physical Link Security | 84.2% | 15.8% |
| 2 | Display Resolution | 100% | 0% |
| 3 | Center Point Brightness (Middle center, front and rear center, side edge points) | 97.4% | 2.6% |
| 4 | Sequential Contrast Ratio | 84.2% | 15.8% |
| 5 | Color Reproduction Accuracy (same points as above) | 44.7% | 55.3% |
| 6 | Electro-Optical Transfer Characteristics (Gamma) | 73.7% | 26.3% |
| 7 | Center Brightness for 3D Playback | 100% | 0% |
| 8 | Brightness Difference Between Eyes | 88.6% | 11.4% |
| 9 | White Field Chromaticity Coordinates for 3D Playback Center Point | 85.7% | 14.3% |
| 10 | Refresh Rate | 57.9% | 42.1% |
| 11 | Pixel Visibility | 78.9% | 21.1% |
| 12 | Dark Field Flickering | 89.5% | 10.5% |
| 13 | Pixel Defects | 60.5% | 39.5% |
| 14 | Sound Field Distribution | 42.1% | 57.9% |
| 15 | Electroacoustic Response Characteristics | 42.1% | 57.9% |
To fully implement the strategic directives of the 20th CPC Central Committee’s Third Plenary Session, which emphasizes “high-quality development as the top priority in building a modern socialist country,” and to evaluate the effectiveness of industry standard implementation, ensure projection quality in LED auditoriums, and protect the legal rights of film copyrights—especially in response to industry concerns regarding early-stage projection quality of domestic LED systems—the China Film Research Institute, in accordance with directives from the National Film Administration, led a joint research initiative. This initiative was carried out in collaboration with China Film Co., Ltd. and Huaxia Film Distribution Co., Ltd., forming a joint LED auditorium survey group. Using DY/T 8–2023: Technical Requirements and Measurement Methods for Digital Cinema LED Auditoriums as the technical benchmark, the team conducted a quality and copyright protection survey in 38 digital LED cinema auditoriums across 26 cities (including Beijing, Tangshan, Taiyuan, Ordos, Xi’an, Zhengzhou, Wuhan, Changsha, Nanchang, Fuzhou, Taizhou, Jiaxing, Hangzhou, Shanghai, Zhenjiang, Nanjing, Jinan, Chengdu, Chongqing, Guiyang, Nanning, Shenzhen, Guangzhou, Zhuhai, Haikou, and Sanya) in August 2024. Survey results indicate that most exhibitors, cinema operators, and manufacturers followed the standard requirements during construction and retrofit of LED auditoriums. However, some auditoriums showed non-compliance in key areas such as copyright protection mechanisms, and optical/acoustic performance indicators (see Table 1).
3. Analysis of Key Issues
Based on findings from the 38 surveyed LED auditoriums, the joint research group identified the following prominent issues:
(1) Inadequate calibration according to standard Upgrading to LED projection involves more than replacing hardware—it requires post-installation calibration in accordance with DY/T 8–2023, to unlock the full advantages of LED technology. A significant number of operational LED auditoriums failed to meet optical and acoustic performance standards. This was due in part to subpar hardware and, more critically, the lack of proper post-installation calibration. Particularly concerning was the sound reproduction system, where less than 40% of relevant equipment had undergone onsite tuning. Upon requiring selected theaters to re-calibrate on-site, the electroacoustic frequency response curves mostly aligned with standard requirements—confirming that calibration is essential.
(2) Inadequate safety management after module installation or replacement
After installing or replacing LED modules, some auditoriums failed to properly secure hardware components, resulting in exposed signal cables and inactive physical security functions. The physical security of the signal chain is critical to preventing content piracy. According to industry standards, when the playback server/IMB and LED controller cabinet are opened, the system should automatically activate its physical security mechanism, lock playback, and halt decrypted content transmission. However, several auditoriums were found with unsecured back panels and inactive protection systems, leaving decrypted signal paths vulnerable—even though playback continued normally, the risk of piracy was significantly elevated.
(3) Poor dark-scene performance; grayscale color coordinates deviate excessively
Dark-field brightness is a critical metric for evaluating dynamic range in LED displays. Some LED panels suffered from defective dark-field rendering due to flaws in dithering algorithms, chipsets, or power drive design. Issues observed included:
Inactive pixel rows during dark scenes
RGB subpixels lighting inconsistently within single pixels
Grayscale step #1 failing to activate
Color coordinate deviations beyond standard tolerances
These problems degraded black-level detail and overall image quality.
(4) Significant deviations in brightness and color at front-row seats; visible pixel structures
To ensure a consistent viewing experience from all seating zones, the standard requires center brightness across various seating points (center row, first and last rows, left and right extremes) to remain within (48.0 ± 10.2) cd/m², and color reproduction to meet DCI-P3 tolerances. Viewers in the front row must not be able to perceive pixel structures or visible gaps between LEDs. However, due to:
Limited viewing angles of some LED panels
Steep upward viewing angles from front-row seats
Excessively short distances between front seats and screens
Vertical LED lamp bead layouts
…some auditoriums experienced noticeable red-blue color shift, visible pixel materials, and panel reflection artifacts, which negatively impacted the front-row viewing experience.
(5) Poor module manufacturing, assembly, and maintenance practices
Pixel defects are symptomatic of weaknesses in manufacturing quality, onsite assembly, and maintenance practices. Survey findings included:
Inconsistent spacing between LED beads and panel edges
Uneven lamp bead quality
Lack of recalibration after module replacement
Poor module flatness and alignment
These issues resulted in dead pixels, brightness variation at seams, noticeable misalignment, and color inconsistency between modules—all of which detract from image integrity.
(6) Suboptimal audio performance in non-acoustically transparent LED screens
Accurate sound reproduction and uniform loudness are essential for immersive cinema experiences. In non-acoustically transparent LED setups, main speakers cannot be installed behind the screen, as in traditional setups, and are instead mounted around the LED perimeter.
Without proper compensation or redesign of the audio system to account for:
Screen sound reflectivity
Speaker repositioning
Limited directional control
…more than 50% of surveyed auditoriums exhibited poor sound field coverage, uneven frequency response, and narrow center audio localization zones. These problems were particularly pronounced in the front rows, leading to inconsistent audio imaging and degraded immersive experience.
4. Application of New LED-Related Technologies
In this survey, special attention was given to the innovative application of domestic LED technologies.
(1) Application of Acoustically Transparent LED Screens
The survey identified one domestic LED auditorium that utilizes an acoustically transparent LED display. In this theater, the high-frequency and mid-frequency drivers of the main speaker system were embedded directly behind the acoustically transparent LED modules, while the low-frequency drivers were installed below the LED screen—effectively replicating the speaker positioning used in traditional projection setups.
Testing results showed that the main channel’s electroacoustic response met the ISO 2969 standard curve, with consistent sound reproduction across front and rear seating areas. The overall sound field distribution complied with relevant technical standards, effectively resolving the image-sound misalignment issue inherent to non-acoustically transparent LED screens and eliminating acoustic interference caused by LED screen reflections.
(2) Application of High Dynamic Range (HDR) Technology
The survey found that, among all sites evaluated, only the China Film CINITY LED auditorium had preliminary capability for HDR playback. As a result, HDR projection performance was tested specifically in this venue. Findings revealed that the CINITY LED auditorium demonstrated strong HDR performance, particularly in terms of peak brightness and sequential contrast ratio. This indicates a promising direction for early adoption of advanced cinema formats in domestic LED projection systems.
The application of domestic acoustically transparent LED screen technology and HDR projection not only enhances the viewing experience in LED auditoriums but also provides robust technical support for China’s independent innovation and the continued progress of its film industry.
Film Standards: Guiding Regulated Development and Future Direction
1. Recommendations for LED Cinema Projection
The Third Plenary Session of the 20th CPC Central Committee emphasized: “Improve the national standards system and use national standards to guide the optimization and upgrading of traditional industries.” In line with this directive, and to promote the dissemination and implementation of DY/T 8–2023: Technical Requirements and Measurement Methods for Digital Cinema LED Auditoriums, as well as the research, development, and large-scale deployment of domestic LED projection systems, the China Film Research Institute offers the following recommendations based on the current application status and future development trajectory of domestic LED projection technology:
Enhance the promotion and implementation of DY/T 8–2023, increase policy support for domestic LED cinema technology, and gradually encourage theaters to adopt domestic LED projection systems, thereby advancing the scale of application and overall industry upgrade.
Conduct direct consultations and impose corrective deadlines on non-compliant manufacturers. Those who fail to make timely corrections should be monitored by industry associations, and necessary actions may be taken to prevent “inferior products driving out superior ones” in the early stages of market deployment.
Strengthen safety maintenance protocols for LED auditoriums, and establish mechanisms for random inspections and unannounced audits. If severe physical security vulnerabilities—such as unsecured back panels or exposed signal cables—are identified and remain unresolved, the cinema should be restricted from receiving film decryption keys.
Consider establishing a management framework for LED auditoriums and strengthen standard enforcement. All newly installed LED screens should undergo mandatory testing and periodic inspections. Only auditoriums that meet the standards should be granted access to digital film keys.
Accelerate the development and distribution of LED-specific DCP masters, and create standardized mastering and screening channels. Continue to provide LED-exclusive content that fully leverages the unique visual capabilities of LED technology. Establish a dedicated certification mechanism to ensure that only auditoriums compliant with relevant standards can play LED-optimized versions of theatrical films.
Establish a coordinated innovation mechanism uniting industry, academia, research, and application. Focus on solving core technical challenges in domestic LED projection through clear upgrade paths and R&D initiatives. Align with global trends and work toward international adoption of China-developed technologies, positioning China as a leader in next-generation display innovation.
Develop a comprehensive standardization system for digital cinema LED production, distribution, and exhibition, guiding the sustained and healthy growth of China’s domestic LED cinema technology.
Accelerate the launch and internationalization of standards for LED mastering, optics, and acoustics. Promote the establishment of an international LED cinema standards system grounded in China’s intellectual property and industrial strengths, contributing to the global shift from “Made in China” to “Standardized by China.”
2. International Strategy for LED Cinema Standards
President Xi Jinping has stated: “He who sets the standards holds the power of discourse; he who controls the standards claims the strategic high ground.” As China’s technical counterpart to ISO/TC 36, the China Film Research Institute is committed to leading the industry toward higher standards and to advancing the internationalization of Chinese film technology standards.
To gain a strategic edge in both R&D and market expansion, and to secure influence over international standards for LED cinema projection, the China Film Research Institute submitted a proposal in March 2024 to ISO/TC 36 for the development of an international standard on optical specifications for digital LED cinema auditoriums—marking a key milestone in establishing a global LED cinema projection standards framework.
Looking ahead, under the guidance of national regulatory authorities, the institute will actively pursue the development of international standards for acoustic performance and mastering in LED cinemas, aiming for full coverage of the LED projection ecosystem. This strategy will support China’s efforts to secure global leadership and influence in LED cinema projection technologies and international trade.
With the light of science illuminating the path of cinema, and the torch of standards guiding industry prosperity, the China Film Research Institute will continue leveraging its technical strengths in research, inspection, and standards development. It is committed to advancing China’s independent innovation in film technology and promoting high-quality growth across the industry—contributing to China’s emergence as a world leader in cinema, culture, and science & technology.
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[10–20] Omitted.
