Reducing the complexity of NCL player implementations

• Guilherme Augusto Ferreira Lima PUC-Rio
• Luiz Fernando Gomes Soares PUC-Rio
• Roberto Gerson De Albuquerque Azevedo PUC-Rio
• Márcio Ferreira Moreno PUC-Rio

Resumo

In this paper, we present an approach for reducing the complexity of NCL player implementations. This approach consists, basically, in introducing in the player's architecture an initial conversion step that removes all syntactic sugar and reuse features from the source language. The output of this step, a redundancy-free version of the original input, is then fed to the player that interprets it and creates a corresponding multimedia presentation. In particular, we propose the use of the NCL Raw profile as this intermediate language. The Raw profile is an (almost) redundancy-free profile that is compatible with the NCL 3.0 EDTV (Enhanced Digital TV) profile, a property that guarantees a seamless integration with current EDTV profile implementations. The main targets of the proposed approach are NCL players running on HTML browsers. We discuss how the solutions presented by NCL4Web, WebNCL, and Ginga Plug-in can be tuned to overcome some problems pointed their authors. The same problems arise in similar contexts for other declarative languages, e.g., SMIL, and the solutions presented here can also be extended to those systems.