Audiovisual synchrony: Cross-modal transient structure and tempo

What are the considerations of the composer when designing music to accompany a visual? Music is purposefully included within audiovisual products with considered reason; motivic, thematic, emotive, semantic or otherwise. Ultimately, music is employed to affect an audiovieweri, yet the consequences of this multi-modal interaction lacks clarity. Investigating cross-modal interaction at the level of basic exposure to audiovisual works provides a foundation in understanding the audioviewer's percept.
The moving image and music are intrinsically temporal and consequently carry rhythmic potential. In the context of concurrent non-literal music (often referred to as ‘background’ or ‘non-digetic’ music) and moving images, our unified perception of the presentation is structured upon the interpretation of intrinsic audiovisual rhythms. Such rhythms are constructed via the periodic structure of transients within their individual modalities, and crucially cross-modally as auditory and visual transient patterns interact.
Multimodal integration studies have shown that synchronous audiovisual stimuli will bind, creating a unified percept functioning to increase the 'transientness' of such events. Dynamic attending theory understands that attention is subject to internalised oscillations, following peaks and troughs to create an oscillation of attentional magnitude cycles. The potential for auditory rhythmic manipulation to influence the unified audiovisual percept is engaging.