【摘要】：在信息化高速發(fā)展的當(dāng)今社會,視音頻等作為信息的載體,在社會生活的各個領(lǐng)域中起著越來越重要的作用。然而,由于數(shù)字視音頻信息具有大量冗余信息,并且占用的存儲空間極大,限制了多媒體技術(shù)的發(fā)展。在這種情況下,由國際電信聯(lián)合會視頻編碼專家組和國際化標(biāo)準(zhǔn)組織運動圖像專家組聯(lián)合制定的H.264視頻壓縮標(biāo)準(zhǔn),以其高性能的壓縮效率和優(yōu)秀的圖像質(zhì)量,成為目前最主流的視頻處理協(xié)議。H.264通過運動估計/運動補償(MP/MC)消除視頻時間冗余,對差值圖像進(jìn)行離散余弦變換(DCT)消除空間冗余,對量化后的系數(shù)進(jìn)行可變長編碼(VLC)消除統(tǒng)計冗余,獲得了極高的壓縮效率。由于其計算復(fù)雜度,目前主流的實現(xiàn)方式主要是基于SoC+ASIC的專用集成電路和DSP軟件實現(xiàn)。 由于H.264在提升編解碼性能的同時所付出的代價是成倍增加算法復(fù)雜度,并且實際應(yīng)用中人們對視頻解碼的實時性要求比較高。已有的算法多是基于PC通用處理器實現(xiàn)的。雖然近年來ARM處理器以及嵌入式技術(shù)發(fā)展迅猛,但畢竟處理能力有限,并且存儲能力有限,因此必須進(jìn)行移植和優(yōu)化,才能滿足實際應(yīng)用需要。本文首先對H.264標(biāo)準(zhǔn)及其新特性進(jìn)行了詳細(xì)的介紹,分析了解碼耗時較多的函數(shù)及模塊。然后以友善之臂的mini2440開發(fā)板為硬件平臺,對Linux系統(tǒng)、bootloader、內(nèi)核的移植以及根文件系統(tǒng)的制作進(jìn)行了詳細(xì)的說明。將基于H.264標(biāo)準(zhǔn)的X264、ffmpeg等參考軟件進(jìn)行交叉編譯后移植到ARM平臺,并針對ARM平臺特點進(jìn)行了編譯優(yōu)化和代碼優(yōu)化。其中編譯優(yōu)化是選擇合適的交叉編譯環(huán)境以及配置最佳的編譯參數(shù),從而生成效果更好的目標(biāo)軟件；代碼級優(yōu)化則是包括了去除冗余代碼、重寫循環(huán)結(jié)構(gòu)以及匯編優(yōu)化等等。最后完成解碼播放,并給出了實驗測試結(jié)果以及評價。實驗結(jié)果表明,對于qcif分辨率的視頻流,可以達(dá)到實時解碼和播放。
[Abstract]:As the carrier of information, video and audio plays an increasingly important role in various fields of social life. However, digital video and audio information has a lot of redundant information and takes up a lot of storage space, which limits the development of multimedia technology. In this case, the H.264 video compression standard, developed jointly by the International Telecommunication Union Video coding expert Group and the International Standards Organization moving Image expert Group, is designed for its high compression efficiency and excellent image quality, H.264 uses motion estimation / motion compensation (MP/MC) to eliminate video time redundancy, and uses discrete cosine transform (DCT) to eliminate spatial redundancy. The variable length coding (VLC) is used to eliminate the statistical redundancy of the quantized coefficients, and the compression efficiency is very high. Due to its computational complexity, the main implementation methods are mainly based on SoC ASIC and DSP software implementation. The cost of H.264 in improving the performance of codec is multiplying the complexity of the algorithm, and the real time requirement of video decoding is very high in practical applications. Most of the existing algorithms are based on PC general purpose processor. Although the ARM processor and embedded technology have developed rapidly in recent years, the processing capacity is limited and the storage capacity is limited, so it is necessary to transplant and optimize to meet the practical application needs. In this paper, the H.264 standard and its new features are introduced in detail, and the decoding functions and modules are analyzed. Then using the mini2440 development board of friendly arm as the hardware platform, the Linux system, the transplantation of the bootloader, kernel and the manufacture of the root file system are described in detail. The X264ffmpeg reference software based on H.264 standard is cross-compiled and transplanted to the ARM platform, and the compiler and code optimization are carried out according to the characteristics of the ARM platform. Compiler optimization is to select the appropriate cross-compilation environment and configure the best compilation parameters, so as to generate better target software. Code level optimization includes removing redundant code, rewriting loop structure, assembly optimization and so on. Finally, the decoding and playing are finished, and the experimental test results and evaluation are given. Experimental results show that real-time decoding and playback can be achieved for qcif resolution video streams.
【學(xué)位授予單位】：長江大學(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)期刊論文 前3條

1 林帥;;信息冗余的分類與特征[J];畢節(jié)學(xué)院學(xué)報;2011年05期

2 齊兵;王群生;楊春玲;;H.264解碼芯片的比較與研究[J];電視技術(shù);2006年09期

3 陳維安;李典;余松煜;錢團(tuán)結(jié);;H.264軟件解碼器的優(yōu)化[J];數(shù)據(jù)采集與處理;2005年04期

相關(guān)博士學(xué)位論文 前2條

1 詹瑾瑜;SoC軟/硬件協(xié)同設(shè)計方法研究[D];電子科技大學(xué);2006年

2 張春榮;數(shù)字視頻DCT域轉(zhuǎn)碼技術(shù)研究[D];上海交通大學(xué);2007年

相關(guān)碩士學(xué)位論文 前1條

1 程愷英;MPEG標(biāo)準(zhǔn)間轉(zhuǎn)碼的研究及一個轉(zhuǎn)碼方案的實現(xiàn)[D];華中科技大學(xué);2005年

，

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