A scheduling scheme for multiplexing extra streaming data into digital TV programs

In digital TV systems, variable bitrate encoding is usually used to improve the bandwidth usage efficiency. Since the transmission channel has a fixed bandwidth, this leaves some portions of the bandwidth unoccupied. This free space can be used to transmit extra data to enhance the TV content, which can be either discrete, like text, or streaming, like video and audio. We address the problem of adding time-sensitive streaming data to a TV program. The crucial part of this problem is a scheduling algorithm that guarantees the on-time delivery of the incidental data to the decoder. We present a sophisticated time-sensitive scheduling algorithm for off-line multiplexing of TV programs and incidental streaming data. The two important features of our algorithm are: 1) it minimizes the presentation delay for incidental and main streams; 2) it minimizes the required decoder buffer size for incidental data. Comparing the experimental results of our algorithm with existing scheduling methods shows that our algorithm significantly reduces the presentation delay and the decoder buffer size for the incidental streams.