Abstract: This paper presents an exploratory view of multimedia processing and transport issues for the wireless personal terminal scenario. In this scenario, portable multimedia computing devices are used to access video/voice/data information and communication services over a broadband wireless network infrastructure. System architecture considerations are discussed, leading to identification of a specific approach based on a unified wired $PLU wireless ATM network, a general-purpose CPU based portable terminal, and a new software architecture foe efficient media handling and quality-of-service (QoS) support. The recently proposed 'wireless ATM' network concept is outlined, and the associated transport interface at the terminal is characterized in terms of available service types (ABR, VBR, CBR) and QoS. A specific MPEG video delivery applications with VBR ATM transport and software decoding is then examined in further detail. Recognizing that software video decoding at the personal terminal represents a major performance bottleneck in this system, the concept of MPEG encoder quantizer control with joint VBR bit-rate and decoder computation constraints is introduced. Experimental results are given for software decoding of VBR MPEG video with both VBR usage parameter control (UPC) and decoder CPU constraints at the encoder, demonstrating improvements in delivered video quality relative to the conventional case without such controls.!17
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