Comment by profpandit

Re: b) For video, the encoder contains a model of the decoder, including the amount of buffering available to the decoder. The bit-rate controller at the encoder uses this model to ensure that the decoder always has the right amount of data in its input buffers. It also ensures that the information rate of the channel is matched with that of the compressed stream in a live transmission setting. The transport scheme which operates at a layer below the codec, therefore only needs to take care of delay and packet delivery/loss related issues over the channel. Media is typically transmitted over UDP.