IPTV video services are increasingly being considered for delivery to mobile devices over broadband wireless access networks. The IPTV streams or channels are multiplexed together for transport across an IP core network prior to distribution across the access network. According to the type of access network, prior bandwidth constraints exist that restrict the multiplex data-rate. This paper presents a bandwidth allocation scheme based on content complexity to equalize the overall video quality of the IPTV sub-streams, in effect a form of statistical multiplexing. Bandwidth adaptation is achieved through a bank of bit-rate transcoders. Complexity metrics serve to estimate the appropriate bandwidth share for each stream, prior to distribution over a wireless or ADSL access network. These metrics are derived after entropy decoding of the input compressed bit-streams, without the delay resulting from a full decode. Fuzzy-logic control serves to adjust the balance between spatial and temporal coding complexity. The paper examines constant and varying bandwidth scenarios. Experimental results show a significant overall gain in video quality in comparison to a fixed bandwidth allocation.
