Effective video resources are assumed to promote learner engagement, but the extent to which this occurs is unclear. This study examines learners' engagement with instructor-generated video. It contributes an analytical synthesis of qualitative and quantitative data that provides the basis for investigating the extent to which, and how, learners engage with video resources provided in their courses. Specifically, three dimensions of learner engagement with video are studied: behavioural, cognitive and affective. The study contributes to educational technology research by identifying distinctive patterns of learner control over the use of video which diverges from instructors' assumptions. It shows the complex and nuanced features of cognitive and affective engagement. Videos can have positive effects, but inappropriate use of technical features results in learner disengagement. This study contributes a novel use of signalling theory, suggesting the importance of instructor signals concerning relevance, focus and utility as a feature of video generation, as a prerequisite of cognitive engagement. A research and theory development agenda is developed, locating video-based learning in student contexts as a basis for explaining both engagement and disengagement with video technology affordances.