DRM optimization for stitched media file rate adaptation

Digital rights management (DRM) and video quality are two important issues for content providers. DRM plays a critical role in enforcing monetization policies while video quality is key for protecting brand integrity. For stitched media file-based (SMF) rate adaptation schemes which rely on low latency seek operations, a seek friendly DRM encryption scheme is required. This paper describes our stream cipher-based DRM encryption scheme which enables secure SMF rate adaptation. We provide a model for and discuss the trade-offs involved in optimizing rate adaptation latency within our scheme. Our SMF scheme is one of a number of HTTP video delivery implementations that we have commercially deployed on the AndroidTM and Blackberry^® mobile platforms and that use our DRM. Though the DRM scheme works with both SMF and segment-based approaches, this paper focuses on SMF considerations. We include cipher performance results from actual device tests, as well as rate adaptation latency results from our production implementation.