NCL Users API: gingaf support and new proposed user attribute for <rule>

• Alan L. V. Guedes PUC-Rio
• Paulo Victor Borges PUC-Rio
• Daniel Moraes PUC-Rio
• Sergio Colcher PUC-Rio

DOI: https://doi.org/10.5753/webmedia_estendido.2026.34167

Resumo

The SBTVD TV 3.0 specification proposes a paradigm shift for its middleware, Ginga, from traditional isolated single-viewer set-top box experiences toward multi-user personalized interactive environments. In this paper, we present the implementation of the NCL Users API in gingaf, an open-source cross-platform Ginga implementation. We demonstrate how gingaf handles dynamic user profile resolution, user settings property binding, and profile data initialization. Furthermore, we propose an extension to the NCL Users API to address the verbosity of causal link assessments by extending NCL’s <rule> element with a user attribute. This attribute allows conditional presentation using elements. Finally, we verify compliance and validate our implementation in multi-user content scenarios.

Palavras-chave: Digital Television, TV 3.0, Ginga, NCL

Referências

ABNT. 2023. ABNT NBR 15606-2: Digital Terrestrial Television – Ginga-NCL for Fixed and Mobile Receivers – XML Application Language for Application Coding. Technical Report. Associação Brasileira de Normas Técnicas.

ABNT. 2024. ABNT NBR 15608-4: Digital Terrestrial Television – TV 3.0 Application Coding Specification and NCL Users API. Technical Report. Associação Brasileira de Normas Técnicas.

Joel dos Santos, Li-Chang Shuen Cristina Silva Sousa, Carlos Soares Neto, Guido Lemos, Sérgio Colcher, Marcelo F. Moreno, and Débora Muchaluat-Saade. 2026. An Overview of the TV 3.0 Application Coding Layer Specification. IEEE Transactions on Broadcasting 72, 1 (2026), 1–15. DOI: 10.1109/TBC.2026.3689351

Alan Guedes. 2026. gingaf: Headless and Multiplatform Execution of ITU-SBTVD NCL Applications. In Proceedings of the 34th ACM International Conference on Multimedia (Rio de Janeiro, Brazil) (MM ’26). DOI: 10.1145/3767308.3834744

ITU-T. 2009. H.761: Nested Context Language (NCL) and Ginga-NCL for IPTV Services. Technical Report. International Telecommunication Union, Geneva, Switzerland.

Luiz Fernando Gomes Soares and Rogério Ferreira Rodrigues. 2010. Nested Context Language 3.0: Part 1 – NCL Language. In Monografias em Ciência da Computação. PUC-Rio.

Gabriel Souza, D. Silva, M. Delgado, and R. Rodrigues. 2020. Interactive 360-Degree Videos in Ginga-NCL Using Head-Mounted Displays as Second Screen Devices. In Proceedings of the 26th Brazilian Symposium on Multimedia and the Web. 113–120. DOI: 10.1145/3428658.3430972