The Scalable Video Coding extension (SVC) of the H.264/AVC standard is widely considered for IPTV. SVC supports a variety of scalability modes, including temporal, spatial as well as coarse-grain and medium-grain quality scalabilities. In this paper, we first give an overview of Coarse-Grain quality Scalability (CGS). We generate traces of CGS encodings of long CIF resolution video sequences; the traces provide a simple yet effective characterization of CGS encoded video for performance evaluation of video transport systems, including IPTV systems. We conduct a detailed statistical analysis of the CGS video traces. We compare the bit rate-distortion (RD) and the bit rate variability-distortion (VD) performances of scalable CGS encodings with those of non-scalable SVC single layer encodings. We thus quantify the tradeoff between the rate adaptability afforded by CGS encoding and the cost in terms of RD efficiency compared to non-scalable single-layer video.