| With the development of Internet facilities, the needs of online HD livestreaming broadcasting (HLSB) is increasing dramatically in the area ofproducts promoting, attractions propaganda, small-scale sports competitionsharing and etc. However, existing commercial product or experimentalsystems have many comings, especially in HD-streaming supporting, videoquality assurance, transmission efficiency and interactive experience. Thus,designing and optimization of the HLSB system with good compatibility,real-time, robustness and interactivity is of theoretical significance andpractical value.In this paper, a complete HLSB has been designed and implemented,whose modules include HD streaming encoding, interactive controlling,multi-level transmission, streaming decoding and playing. And the keyoptimizing techniques in video quality assurance and transmissionefficiency improving are researched. The main contributions of this paperare as follow:(1)The Implemented HLSB system supports IP camera as video source,which greatly improves video quality, makes deployment easier andsupports remote controlling. In addition, the HLSB system has a distributedCND-liked (Content Delivery Network) data transmission mode, allowingstreaming transmission adapting end-users’ network condition, thusimproving image quality and reducing broadcasting lag.(2)The end-user module of the HLSB system is implemented based onFFmpeg development lib, which makes it easier to transplanting andexpanding. And multi-level streaming and synchronization mechanism between audio and video data are designed in end-user module. Moreover,the end-user module can be used as a web plugin easily.(3)In order to optimize the video quality of HLSB system in poornetwork, a distortion-estimation-based selective automatic repeat requestalgorithm (ARQ) for transmission of H.264/AVC and H.264/SVC streaminghas been proposed.(4)In order to reduce the requirements of media servers’ upload rateand assure good interactive of the HLSB system, a data transport optimizingmechanism combining the feature of peer-to-peer and CDN-likedmechanism has been designed.The simulation results show that proposed selective ARQ algorithmcan dramatically improving video quality in poor network condition, being2-3dB better than existing algorithms averagely. Meanwhile, proposed datatransport optimizing mechanism can reduce90%uploading rate of themedia severs in large-scale application, and assuring low broadcasting lagfor the nodes with interactive application. |
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