| Sign language is the most natural way for the deaf to communicate and visual language which is created by arm movement, expression, lips, and other body posture to express ideas. Sign language is more complicated and difficult to study, because it increases the arm movement and has the phenomenon of the face is blocked by hands. With the rapid development of wireless communication technology, the improvement of wireless network bandwidth and the popularization of mobile devices which have multimedia processing ability, the constraints which come from the power consumption and processing capacity are stronger and stronger. The power constraint on wireless terminal has become the main obstacle to the rapid development of mobile multimedia industry. Therefore, how to realize the optimal compromise between performance and energy consumption of sign language video coding and transmission in the case of limited energy on mobile terminal, which has become the key issues facing mobile terminals. For the above problem, researchers put forward power-aware video coding and transmission method. The power-aware video coding and transmission method is based on Shannon classical rate distortion theory, introduces the concept of energy and sets up the power-rate-distortion model based on coding and transmission parameters. So, the video data gain the optimal dynamic between power loss, channel bandwidth and the coding distortion under meeting the power and rate constraints. To be specific, this thesis works are as following:(1) Set up the video coding model of energy consumption under different energy states. According to the battery energy state of mobile terminal, we can get three different energy levels. Under the condition of energy level division, this paper analyzes the influence from encoding parameters for energy consumption of coding in video coding system, and finally we find the quantitative parameters which are the main parameters affecting the energy consumption of coding. Therefore, the quantitative parameters are chosen as the model parameters and the energy consumption model of video coding is established by quantization step. The experimental results show that the accuracy of the model.(2) Establish video coding rate-distortion model under different energy states. For video encoder, the output bit rates and distortion are related to quantitative parameters. Therefore, on the premise of battery energy state division, the rate-distortion model which based on quantization step is established under the three energy levels.(3) Establish video coding power-rate-distortion model under different energy states. After carefully analyzing the effect of quantitative parameters for video coding, the paper points out the influence from the quantization step for video coding energy consumption, video coding rate and the video coding quality. In the end, quantization step as modeling parameters, respectively establish the energy consumption model, rate model and distortion model under three different energy levels. In this paper, the established model reveals the nature of the relationship between coding energy consumption, coding rate and coding distortion.(4) Realize the optimal allocation between video encoding and transmission energy. Under the power-rate-distortion model of video coding and transmission are established, we obtain allocation proportion of coding and transmission energy under three kinds of energy levels, finally realize the optimal allocation of energy resources and extend battery life of mobile devices.The research results show that the power-rate-distortion model which is established in this paper can accurately reflect the relationship that depend on each other, restrict each other between the energy from the video coding, coding bit rate and coding distortion; The proposed energy optimization allocation algorithm can realize the energy optimization allocation in video transmission system and maximize the extension of video talk time. |
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