A flexible decoder buffer model for JVT video coding

Video coding standards require that a compliant bit stream be decodable by a hypothetical decoder that is conceptually connected to the output of an encoder and consists of a decoder buffer, a decoder, and a display unit. The encoder must create a bit stream so that the hypothetical decoder buffer does not overflow or underflow. Previous decoder models assume that a given bit stream will be transmitted through a channel of a given constant bit rate and will be decoded (after a given buffering delay) by a device of some given buffer size. Therefore, these models are quite rigid and do not address the requirements of many of today's important video applications such as broadcasting live video or streaming pre-encoded video on demand over network paths with various peak bit rates to devices with various buffer sizes. In this contribution, we present a new hypothetical reference decoder for JVT that is more general and flexible than those defined in prior standards and provides significant additional benefits.