本文選題：H.264算法優(yōu)化　切入點：幀內(nèi)預(yù)測　出處：《蘭州理工大學(xué)》2012年碩士論文

【摘要】：近些年來視頻解碼技術(shù)飛速發(fā)展，低分辨率、低質(zhì)量的多媒體視頻已不能滿足人們的需求。近些年來隨著3G技術(shù)以及智能手機(jī)的廣泛應(yīng)用，人們對手持多媒體視頻傳輸?shù)男枨笤絹碓狡惹�，但是移動終端或者無線技術(shù)傳輸?shù)倪^程中對多媒體信息傳輸，尤其是高質(zhì)量的視頻多媒體傳輸對系統(tǒng)硬件以及網(wǎng)絡(luò)帶寬往往具有很高的要求。所以，視頻的傳輸需要進(jìn)行壓縮處理。視頻編解碼技術(shù)是實現(xiàn)手持終端視頻無線傳輸?shù)闹匾诵募夹g(shù)。H.264編解碼技術(shù)已經(jīng)廣泛應(yīng)用在PC機(jī)為主的家用平臺，成為下一代視頻壓縮技術(shù)強有力的競爭者。但在手持移動終端設(shè)備當(dāng)中，H.264由于其編碼較為復(fù)雜并且對硬件處理性能要求較高等原因還未大量使用。如何能夠?qū)⒁呀?jīng)非常優(yōu)秀的H.264編解碼技術(shù)應(yīng)用在手持移動終端，其關(guān)鍵是在盡量不改變視頻質(zhì)量的情況下相應(yīng)的提高編碼效率，降低算法的復(fù)雜度，在硬件環(huán)境有限的情況下滿足H.264編解碼正常運行并達(dá)到良好效果，所以對其算法優(yōu)化具有重要的研究意義。 根據(jù)上述特點及H.264算法中需要解決的問題，本文從以下幾點對H.264算法進(jìn)行研究與優(yōu)化。 1、深入學(xué)習(xí)H.264算法的幾種關(guān)鍵技術(shù)，了解這些關(guān)鍵技術(shù)國內(nèi)外研究現(xiàn)狀，通過對比其它解碼器，解釋了H.264為何優(yōu)于其它算法，為以下研究打下基礎(chǔ)。 2、由于靜止畫面中其像素之間相關(guān)性非常強，通過對幀內(nèi)預(yù)測算法深入研究，本文提出了一種基于閾值法與方向梯度法相結(jié)合的快速選擇預(yù)測模式算法。該算法首先將用設(shè)置閾值的方式將算法簡化，如果滿足閾值設(shè)置條件直接進(jìn)入DC模式，如果不滿足條件進(jìn)入簡化后的方向預(yù)測算法。仿真結(jié)果顯示，利用該算法能夠在基本不改變視頻質(zhì)量的情況下降低60%以上的運算時間，具有一定的實用性。 3、上述方法能夠很解決靜止畫面的壓縮效率，但對運動較為強烈的畫面容易產(chǎn)生圖像失真和較強的飄移效應(yīng)。對于運動劇烈的畫面本文對運動補償算法分析并優(yōu)化該算法，提出一種基于1/4像素法的快速算法。在實驗分析計算的基礎(chǔ)上得到像素中需要大量計算的部分并引入用于像素插值濾波器進(jìn)行濾波，通過此算法能夠降低運算的復(fù)雜度，減少運算時間，，在實驗結(jié)果中證明該算法可以有效地降低劇烈運動畫面中總的計算復(fù)雜的解碼過程，而不會帶來明顯的圖像質(zhì)量損失和嚴(yán)重的漂移效應(yīng)。 4、對幀內(nèi)預(yù)測算法以及運動補償算法優(yōu)化后的算法移植入嵌入式系統(tǒng)當(dāng)中，論文選擇基于ARM11的S3C6410開發(fā)板。將WinCE6.0移植入開發(fā)板中，并通過制作簡單播放器來測試視頻優(yōu)化后的效果。
[Abstract]:With the rapid development of video decoding technology in recent years, the low resolution and low quality multimedia video has not been able to meet the needs of people. In recent years, with the wide application of 3G technology and smart phone, The demand for hand-held multimedia video transmission is becoming more and more urgent, but in the process of mobile terminal or wireless technology transmission of multimedia information, In particular, high quality video multimedia transmission often requires high system hardware and network bandwidth. Video coding and decoding technology is an important core technology for wireless video transmission in handheld terminal. H.264 coding and decoding technology has been widely used in PC based home platform. It has become a strong competitor in the next generation video compression technology. However, H.264 has not been widely used in handheld mobile terminal devices due to its complex encoding and high performance requirements for hardware processing. It has been applied to handheld mobile terminal with excellent H.264 coding and decoding technology. The key is to improve the coding efficiency and reduce the complexity of the algorithm without changing the video quality as much as possible, and to meet the H.264 coding and decoding normal operation and achieve good results under the limited hardware environment. Therefore, it is of great significance to study its algorithm optimization. According to the above characteristics and the problems that need to be solved in H.264 algorithm, this paper studies and optimizes H. 264 algorithm from the following points. 1. Study several key technologies of H.264 algorithm, understand the research status of these key technologies at home and abroad, explain why H.264 is superior to other algorithms by comparing other decoders, and lay the foundation for the following research. 2. Because of the strong correlation between the pixels in the still picture, the intra prediction algorithm is studied deeply. In this paper, a fast predictive mode selection algorithm based on the combination of the threshold method and the directional gradient method is proposed. The algorithm will be simplified by setting the threshold, if the threshold setting condition is satisfied and the DC mode is entered directly. The simulation results show that the algorithm can reduce the computation time by more than 60% without changing the video quality, and it has some practicability. 3. The above method can solve the compression efficiency of still picture very well, but it is easy to produce image distortion and strong drift effect for the picture with strong motion. In this paper, the motion compensation algorithm is analyzed and optimized for the picture with violent motion. In this paper, a fast algorithm based on 1 / 4 pixel method is proposed. Based on the experimental analysis and calculation, the part of pixel which needs a lot of computation is obtained and the filter is used to filter the pixel interpolation filter. Through this algorithm, the computational complexity can be reduced. The experimental results show that the proposed algorithm can effectively reduce the total computational complexity of the decoding process in the violent motion picture without obvious loss of image quality and serious drift effect. 4. For the intra-frame prediction algorithm and the optimized algorithm of motion compensation algorithm transplanted into the embedded system, the S3C6410 development board based on ARM11 is selected in this paper. The WinCE6.0 is transplanted into the development board. And through the production of simple players to test the effect of video optimization.
【學(xué)位授予單位】：蘭州理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：TP368.1;TN919.81

【參考文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 梁立偉;H.264幀內(nèi)預(yù)測及變換方法的研究與優(yōu)化[D];合肥工業(yè)大學(xué);2005年

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