Dialogue Understandability: Why are we streaming movies with subtitles?
Helard Becerra Martinez, Alessandro Ragano, Diptasree Debnath, Asad Ullah, Crisron Rudolf Lucas, Martin Walsh, Andrew Hines
TL;DR
This work introduces Dialogue Understandability (DU) as a holistic measure of how viewers follow movie plots under streaming conditions, extending beyond traditional intelligibility to encompass cognitive effort and QoE. It proposes a working definition, a six-factor root-cause framework, and a mapping to QoE and the movie lifecycle, then evaluates existing objective tools through pilot experiments to assess their suitability for DU. The paper highlights gaps in measurement maturity, argues for adaptation and multi-source modeling (audio, video, subtitles, metadata), and discusses practical avenues such as dialogue enhancement and smart subtitling. Its contributions pave the way for targeted datasets and objective tools to predict and improve DU, with implications for accessibility, localization, and user experience in streaming services.
Abstract
Watching movies and TV shows with subtitles enabled is not simply down to audibility or speech intelligibility. A variety of evolving factors related to technological advances, cinema production and social behaviour challenge our perception and understanding. This study seeks to formalise and give context to these influential factors under a wider and novel term referred to as Dialogue Understandability. We propose a working definition for Dialogue Understandability being a listener's capacity to follow the story without undue cognitive effort or concentration being required that impacts their Quality of Experience (QoE). The paper identifies, describes and categorises the factors that influence Dialogue Understandability mapping them over the QoE framework, a media streaming lifecycle, and the stakeholders involved. We then explore available measurement tools in the literature and link them to the factors they could potentially be used for. The maturity and suitability of these tools is evaluated over a set of pilot experiments. Finally, we reflect on the gaps that still need to be filled, what we can measure and what not, future subjective experiments, and new research trends that could help us to fully characterise Dialogue Understandability.
