本文選題：VP9 + 視頻編碼��； 參考：《西安電子科技大學(xué)》2014年碩士論文

【摘要】：VP9是谷歌繼推行VP8后于2013年推行的新一代開源視頻編碼標(biāo)準(zhǔn)。VP9視頻編碼標(biāo)準(zhǔn)保留了原有的傳統(tǒng)的視頻編碼框架,同時(shí)采納了一系列新技術(shù),使其在同等視頻質(zhì)量下碼率較上一代VP8可降低50%。但是壓縮性能提高的同時(shí)也帶來了巨大的編碼復(fù)雜度。本文針對(duì)這一問題研究了VP9視頻編碼標(biāo)準(zhǔn)的幀內(nèi)預(yù)測快速算法,以期望降低編碼復(fù)雜度提高編碼速度,使該標(biāo)準(zhǔn)更適合實(shí)時(shí)性要求較高的業(yè)務(wù)。為了達(dá)到降低編碼復(fù)雜度的目的,本文首先對(duì)VP9視頻編碼的幀內(nèi)預(yù)測過程進(jìn)行了深入的研究和分析;然后在此基礎(chǔ)上,提出了兩種適用于VP9的幀內(nèi)預(yù)測快速算法。分別是幀內(nèi)預(yù)測模式快速選擇算法和幀內(nèi)預(yù)測的塊劃分快速算法。本文針對(duì)VP9幀內(nèi)預(yù)測中模式選擇復(fù)雜度高的問題,提出了一種幀內(nèi)預(yù)測模式快速選擇算法。每一個(gè)64×64的超級(jí)塊需要進(jìn)行6810次模式選擇才能確定最佳劃分方式以及相應(yīng)的最佳預(yù)測模式。通過減少預(yù)測模式的候選模式數(shù)目可以大大減少模式選擇的次數(shù)。本文通過利用相鄰預(yù)測塊的最佳預(yù)測模式和當(dāng)前塊的紋理方向性來減少幀內(nèi)預(yù)測的候選模式。該算法排除了大部分預(yù)測模式,從而降低了編碼復(fù)雜度,節(jié)約了近55%的編碼時(shí)間。針對(duì)VP9幀內(nèi)預(yù)測中塊劃分過程較復(fù)雜的問題,提出了一種幀內(nèi)預(yù)測的塊劃分快速算法。塊劃分過程算法優(yōu)化的大體思路為直接確定某些塊的最優(yōu)劃分方式或者跳過某些不必要的塊劃分方式。首先,確定了影響最優(yōu)塊劃分的因素:空間復(fù)雜度、空間平滑度和編碼量化參數(shù)。然后,根據(jù)這3個(gè)因素和幀內(nèi)預(yù)測中塊劃分的關(guān)系,對(duì)平坦的預(yù)測塊只進(jìn)行較大塊預(yù)測,而對(duì)不平坦的預(yù)測塊則直接跳過大塊預(yù)測只進(jìn)行較小塊預(yù)測。實(shí)驗(yàn)證明該算法對(duì)于運(yùn)動(dòng)和紋理復(fù)雜度不同的序列,在不同的量化參數(shù)下,都能夠在保證視頻編碼效率下降較小的同時(shí),大幅度降低幀內(nèi)編碼的復(fù)雜度從而使編碼時(shí)間得到大幅度減少。
[Abstract]:VP9, Google's new open-source video coding standard. VP9, introduced in 2013 after VP8, retains the traditional video coding framework and incorporates a range of new technologies. Compared with the previous generation VP8, the bitrate can be reduced by 50% under the same video quality. However, the compression performance is improved, but also brings huge coding complexity. In order to reduce the coding complexity and improve the coding speed, the fast intra prediction algorithm of VP9 video coding standard is studied in this paper. In order to reduce the coding complexity, this paper firstly studies and analyzes the intra prediction process of VP9 video coding, and then proposes two fast intra prediction algorithms for VP9. It is a fast selection algorithm for intra prediction mode and a fast block partition algorithm for intra prediction. Aiming at the high complexity of mode selection in VP9 intra prediction, this paper proposes a fast mode selection algorithm for intra prediction. Each 64 脳 64 superblock needs 6810 mode selections to determine the optimal partitioning method and the corresponding optimal prediction model. By reducing the number of candidate patterns, the number of pattern selections can be greatly reduced. In this paper, the best prediction mode of adjacent prediction block and the texture directivity of current block are used to reduce the candidate mode of intra prediction. The algorithm eliminates most prediction modes, thus reducing the coding complexity and saving about 55% coding time. A fast block partitioning algorithm for intra prediction of VP9 is proposed to solve the complex problem of block partitioning in intra prediction. The general idea of block partition algorithm optimization is to determine the optimal partition method of some blocks directly or skip some unnecessary block partition methods. Firstly, the factors affecting the optimal block partition are determined: space complexity, spatial smoothness and coding quantization parameters. Then, according to the relationship between these three factors and block partition in intra prediction, only large blocks are predicted for flat prediction blocks, while smaller blocks are predicted for uneven prediction blocks directly skipping over large blocks. Experiments show that the proposed algorithm can reduce the video coding efficiency under different quantization parameters for sequences with different motion and texture complexity. The complexity of intra-coding is greatly reduced and the coding time is greatly reduced.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN919.81

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相關(guān)期刊論文 前1條

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本文編號(hào)：1805910