Multi-layered video structures are scaled over a range of perceived quality levels. An estimated Mean Opinion Score (eMOS)-based encoder control loop is utilized to determine one or more encoder key performance index (KPI) associated with a particular perceived quality level. A KPI-based encoder control loop is then utilized to guide generation of a hierarchical structure having quality and/or temporal and/or spatial enhancement layers, without recalculating eMOS for the scalable structure. In addition, eMOS is used to guide the generation of a hierarchical structure at best-perceived quality levels for a given bitrate budget. Rate adaptation may occur by dropping segments, changing hierarchical structure, or changing the KPI target values. With the structure scaled as a function of perceived quality, perceived quality is impacted predictably as the encoding rate is adapted.