The rapid evolution in the hardware sector brought up various end user devices like PDAs or cell phones on which online multimedia contents can be consumed. Due to different capabilities of these devices as well as individual user preferences, original multimedia resources have to be adapted in order to fit the specific constraints of such devices and to meet the user requirements. Adapting multimedia contents through user preferences is an important aspect of QoS (Quality of Service). There has been a vast amount of activities in research and standard development in mis area. In this paper, we present methods for adapting multimedia contents to accommodate user preference. In addition, we propose a user preference content value model (u-CVM) that relates the content value of different modalities with resources. Implemented system shows that modality conversion brings a wider range of adaptation for QoS support. Moreover, the proposed approach is to be effective to apply in Digital Multimedia Broadcasting (DMB) and Telematics.