This paper focuses on recent research on unequal error protection random linear coding (UEP RLC) for applications in network coded (NC) multimedia communications. We define a class of UEP RLC called expanding window random linear coding (EW-RLC) and provide exact decoding probability analysis for different importance classes of the source data assuming the Gaussian Elimination (GE) decoder applied at the receiver. Using this analysis, we provide a detailed investigation of the EW-RLC design for the distortion optimized scalable H.264/SVC coded video transmission over packet networks with packet erasures over a range of heterogeneous receivers with varying receiver reception overhead capabilities.