| With the continuous popularization of high-definition video communication services,wireless video transmission has been widely used in people's life and work.In particular,some new video transmission scenarios,such as virtual reality,vehicle cameras,and smart security systems,can be realized under the conditions of real-time and reliable transmission of high-definition video.Therefore,the high-definition video transmission with low-latency and high-reliability has become a new research focus.Specially,considering the fact there area large amount of original video data,it is a key technical problem that how to reduce the overall coding delay and computational complexity while meeting the channel transmission conditions.Besides,it is also necessary to to improve the reliability of video transmission in the wireless channel and obtain excellent image restoration quality.In view of this,these issues need to be addressed at present.To this end,this paper will conduct in-dep th research on the compression codec algorithm of high-definition video with low-latency characteristics and the video stream loading algorithm based on MIMO-OFDM system.The main research content includes the following parts.Firstly,this paper introduces the research background and current development trends at home and abroad,sorts out the development of international codec standards,and sorts out the existing research on low-latency and high-reliability wireless transmission.In addition,three important coding standards are described in details and the corresponding shortcomings are analyzed.Then the related theories about MIMO-OFDM are introduced.Based on the above theoretical knowledge,a video transmission scheme based on MIMOOFDM is given aiming at the low-delay and high-reliability transmission of high-definition video.Secondly,the low-latency high-definition video compression codec algorithm is studied in depth.Aiming at the impact of high-complexity and high-delay coding algorithm introduced by the commonly used coding standards due to the high compression rate,a high-definition video compression coding and decoding algorithm based on integer wavelet transform is proposed.When coding,the proposed algorithm reduces the buffer delay by dividing the patch,selects a suitable wavelet base for wavelet transform,designs a low-complexity rate control algorithm and an easy-to-implement entropy coding algorithm,and then designs a code stream organization format for transmission in the actual channel.When decoding,the video parameters are obtained relying on the code stream format and the entropy decoding is performed according to the parameters.As a result,the wavelet coefficients are obtained and then the inverse wavelet transform is performed to restore the image.The latency and complexity of the above algorithms are compared,After simulation,it is verified that the algorithm in this paper can improve the subjective and objective image quality.Finally,the collecting of high-definition video is realized and the approach of loading the video stream is further studied.Specifically,ADV7612 is employed to receive the HDMI signal to complete the collection of the video signalby the camera,and then an unequal error protection loading algorithm for video stream based on MIMO-OFDM system is proposed to meet the high reliability requirements of wireless video transmission.Since the video code streams through the above-mentioned video encoder have significant difference,an unequal error protection can be performed for this difference.In this paper,the unequal error protection at antenna level and bit level are used at the same time,and channel resources and constellation point resources are prior allocated to important data streams.Based on MATLAB simulation,the experimental results demonstrate that this proposed algorithm can significantly improve the restoration quality of the reconstructed image from the objective and subjective images qualities compared with the random loading approach. |
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