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.