【摘要】：近年來,隨著網(wǎng)絡(luò)技術(shù)、通信技術(shù)以及流媒體技術(shù)的迅猛發(fā)展,承載網(wǎng)、接入網(wǎng)的技術(shù)越發(fā)成熟且在不斷發(fā)展中,基于互聯(lián)網(wǎng)的應(yīng)用服務(wù)已從傳統(tǒng)的FTP、Email、HTTP等逐漸轉(zhuǎn)入到新興的網(wǎng)絡(luò)多媒體應(yīng)用中去,如網(wǎng)絡(luò)電視、IP電話、視頻會議、視頻點播、在線視頻廣告等。由于接入網(wǎng)的異構(gòu)性,用戶網(wǎng)絡(luò)終端的差異性,再加上各種網(wǎng)絡(luò)多媒體應(yīng)用服務(wù)的自身特殊性,根據(jù)不同的服務(wù)對象和網(wǎng)絡(luò)環(huán)境,制定可靠性高的、網(wǎng)絡(luò)自適應(yīng)力強的網(wǎng)絡(luò)多媒體流傳輸策略,是當今網(wǎng)絡(luò)多媒體研究者的研究熱點。本論文課題,針對網(wǎng)絡(luò)多媒體中的視頻部分,就流媒體視頻四大關(guān)鍵技術(shù)中的視頻傳輸技術(shù)加以分析和研究,在分析了當今主流視頻傳輸算法的基礎(chǔ)上,針對各算法優(yōu)劣,再結(jié)合流媒體視頻自身的特點,提出了一種基于TFRC算法改進的視頻傳輸控制策略。針對原始TFRC算法,一是修改了其慢啟動階段初始發(fā)送速率的設(shè)置問題和發(fā)送速率增長過快問題;二是修改了其擁塞避免階段發(fā)送速率持續(xù)性的波動問題。改進后的TFRC算法,更加偏向于提高視頻發(fā)送速率的穩(wěn)定性,減小報文傳輸抖動,以保證視頻畫面流暢度。在論文的實驗驗證部分,通過基于Planet Lab全球性實驗測試平臺的真實網(wǎng)絡(luò)環(huán)境測試,實驗結(jié)果驗證了本視頻傳輸策略具有良好的速率穩(wěn)定性,報文時延抖動較原始TFRC算法有所減小,實驗結(jié)果與預(yù)期目標相一致。本論文的核心是研究視頻傳輸控制算法,盡管如此,一般來說,由于流媒體視頻系統(tǒng)包含了視頻的編碼壓縮、視頻傳輸控制、視頻緩沖處理和視頻解碼播放4大關(guān)鍵技術(shù),所以,為了便于在真實環(huán)境下視頻傳輸系統(tǒng)的測試,本論文課題編碼實現(xiàn)部分,除了實現(xiàn)視頻傳輸控制技術(shù)外,還對視頻緩沖和視頻解碼(并未實現(xiàn)視頻播放)做了流程和算法分析,并加以編程實現(xiàn)。至于視頻的壓縮編碼,則直接采用了預(yù)先已編碼處理好的H.264視頻樣本作為視頻源。
[Abstract]:In recent years, with the rapid development of network technology, communication technology and streaming media technology, the technology of bearer network and access network has become more and more mature and in the continuous development, the application service based on Internet has changed from the traditional FTP,Email,. HTTP and so on gradually turn to the emerging network multimedia application, such as network television, IP telephone, video conference, video on demand, online video advertisement and so on. Due to the heterogeneity of the access network, the difference of user network terminals, and the particularity of various network multimedia application services, according to different service objects and network environments, high reliability is formulated. The network multimedia streaming strategy, which is adaptive to the network, is the research hotspot of the network multimedia researchers. This thesis aims at the video part of the network multimedia, analyzes and studies the video transmission technology among the four key technologies of streaming media video, on the basis of analyzing the mainstream video transmission algorithms, aiming at the advantages and disadvantages of each algorithm, Combined with the characteristics of streaming media video, an improved video transmission control strategy based on TFRC algorithm is proposed. For the original TFRC algorithm, one is to modify the problem of setting the initial transmission rate in the slow start phase and the other is to modify the persistent fluctuation of the transmission rate in the congestion avoidance phase. The improved TFRC algorithm is more inclined to improve the stability of video transmission rate and reduce the jitter of message transmission in order to ensure the smoothness of video picture. In the experimental verification part of the thesis, through the real network environment test based on Planet Lab global experimental test platform, the experimental results show that the video transmission strategy has good rate stability. The packet delay jitter is smaller than that of the original TFRC algorithm, and the experimental results are consistent with the expected target. The core of this paper is to study the video transmission control algorithm. However, generally speaking, the streaming media video system includes four key technologies: video coding and compression, video transmission control, video buffering and video decoding and playback. Therefore, in order to facilitate the testing of video transmission system in real environment, in this thesis, except for the video transmission control technology, the coding realization part of this thesis is introduced. The flow and algorithm of video buffering and decoding (video playback is not realized) are analyzed and programmed. As for video compression and coding, H. 264 video samples which are pre-coded and processed are directly used as video source.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN919.8

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本文編號：2472715