臺灣博碩士論文加值系統

H.264影像壓縮編碼標準自提出以來，其強大的壓縮效能，吸引了許多人的目光。在相同的畫面品質下，H.264只需要相當於MPEG2一半的位元率。
雖然H.264沿用的是傳統的編碼流程，但是在各個區塊加入了許多以往視訊標準所沒有的技術，只要影響壓縮率的有多幅參考畫面、可變區塊大小、1/4像素精度的運動補償、利用鄰近區塊的幅內預測、自適應變長編碼和自適應算數編碼。利用以上技術的組合可以大大提高壓縮性能。
在幅內預測編碼的情況，H.264提供了亮度區塊16x16 4種模式、4x4 9種模式和色度區塊4種模式。因此在計算一個16x16色度塊最佳模式的時候會有16x16 4種加上4x4 9種乘上16個區塊，所以在選擇出一個最適當的模式需要經過繁長的計算代價過程，使的編碼一個宏塊需要花費相當多的計算時間。
本論文提出了一個基於邊緣偵測的模式選擇方法，將符合邊緣偵測所對應的模式判斷出來，將它作為這個區塊的最佳模式，而不能判斷的則執行原本的選擇方法，透過修改參考軟體進行驗證，此方法可以縮短選擇一個mode的時間，同時也能減少編碼時間。

Joint Video Team (JVT) which is composed of International Telecommunication Union (ITU) and Motion Picture Experts Group (MPEG) draws up the standard. H.264 video compression coding standard for compression of its strong performance has attracted the attention of many people. In the same picture quality, H.264 only need half of bit rate by MPEG2.
Compared with all existing video coding standard, H.264 provides some of new coding techniques, such as Multi-picture inter-picture prediction, Variable block-size, Quarter-pixel precision for motion compensation, intra prediction, Context-adaptive variable-length coding (CAVLC) and Context-adaptive binary arithmetic coding (CABAC).Using a combination of these technologies can improve the compression performance.
In the case of intra mode, H.264 provides luma block four modes 16x16, nine 4x4 modes and Chroma block four modes. When calculating the best model, we need to calculate the cost of the various modes. In the selection of a mode most appropriate to go through a long complicated process of calculating the cost, so coding a macroblock takes a considerable amount of computing time.
This paper presents a mode decision of the edge detection method. I detected the edge to find the mode that the corresponding edge as the best mode of the block. By modifying the reference software for authentication, this method can shorten the time to choose a mode, but also can reduce the encoding time.

Chapter 1 Introduction.....................................................1
1.1 H.264 video compression standard...............................1
1.2 Motivation.....................................................3
1.3 Thesis Organization............................................3
Chapter 2 Review of H.264/AVC..............................................5
2.1 H.264/AVC Overview.............................................5
2.2 Features.......................................................6
2.2.1 Intra prediction...........................................6
2.2.1.1 Intra 16×16 prediction...............................7
2.2.1.2 Intra 4 × 4 prediction...........................................8
2.2.1.3 Chroma Prediction Modes..........................................13
2.2.2 Inter prediction.........................................13
2.2.2.1 Variable block-size...................................13
2.2.2.2 Quarter-pixel precision for motion compensation.......15
2.2.2.3 Multi-picture inter prediction........................17
2.2.2.4 Deblocking Filter.....................................17
2.2.3 Integer Transform.........................................18
2.2.4 Entropy coding............................................18
2.2.4.1 CAVLC.................................................19
2.2.4.2 CABAC.................................................19
2.2.5 Flexible Macroblock Ordering..............................20
2.2.6 Switching slices..........................................21
2.2.6.1 SP-slice..............................................21
2.2.6.2 SI-slice..............................................22
2.3 JM Reference Software........................................22
Chapter 3 Intra Mode Decision.............................................25
3.1 Rate estimation in intra mode decision........................25
3.1.1 Rate Distortion Optimization..............................25
3.2 Related work..................................................26
3.2.1 Use ρ-domain to estimation...............................26
3.2.2 Use the parameters of CAVLC to estimation.................27
3.3 Laplacian-based Intra Mode Decision...........................28
3.3.1 Edge Detection............................................30
3.3.2 Histogram.................................................32
3.3.3 The Direction of The Edge.................................33
3.3.4 Proposed Mode Decision....................................34
Chapter 4 Experiment Result...............................................36
4.1 Platform......................................................36
4.2 Measuring tool................................................37
4.2.1 Peak Signal-to-Noise Ratio................................37
4.2.2 Bitrate...................................................37
4.2.3 BDBR and BDPSNR...........................................38
4.2.4 Speed Up..................................................39
4.3 Result........................................................39
Chapter 5 Conclusions.....................................................46
REFERENCES.................................................................47

[1]“Draft ITU-T Recommendation and Final Draft International Standard of Joint Video Specification (ITU-T Rec. H.264 | ISO/IEC 144496-10 AVC)” Joint Video Team of SO/IEC and ITU-T, March 2003
[2]“Generic Coding of Moving Pictures and Associated Audio Information” ISO/IEC 13818-2: Video (MPEG-2), May 1996
[3]“Video Coding for Low Bit Rate Communication, Version 1” ITU-T Recommendation H.263, 1995
[4]“Coding of audio-visual objects - Part 2: Visual” in ISO/IEC 14496-2 (MPEG-4 Visual Version 1), Apr. 1999
[5]T. Wiegand, G.J. Sullivan, G. Bjontegaard, and A. Luthra, “Overview of the H.264/AVC Video Coding Standard,” in the IEEE Transactions on Circuits and Systems for Video Technology, July 2003
[6]H. Kim, and Y. Altunhasak, “Low-complexity macroblock mode selection for H.264-AVC encoders,” Image Processing, 2004. ICIP '04. 2004 International Conference on , vol.2, pp. 765- 768, Oct. 2004
[7]C. H. Tseng, H. M. Wang and J. F. Yang, “Enhanced intra-4x4 mode decision for H.264/AVC coders,” IEEE Transactions on Circuits and Systems for Video Technology, Vol.16, p.p.1027-1032, 2006
[8]Iain E. G. Richardson, ”H.264 and MPEG-4 Video Compression,” Baker & Taylor Books, pp. 159-222, Dec. 2003
[9]T. Wiegand, G.J. Sullivan, G. Bjontegaard, and A. Luthra, “Overview of the H.264/AVC Video Coding Standard,” in the IEEE Transactions on Circuits and Systems for Video Technology, July 2003
[10]G. Sullivan and T. Wiegand, “Video Compression - From Concepts to the H.264/AVC Standard,” in Proceedings of the IEEE, Special Issue on Advances in Video Coding and Delivery, December 2004
[11]D. Marpe, H.Schwarz, and T. Wiegand, “Context-Based Adaptive Binary Arithmetic Coding in the H.264/AVC Video Compression Standard,” in the IEEE Transactions on Circuits and Systems for Video Technology, July 2003
[12]G.J.Sullivan and T. Wiegand, “Rate-Distortion Optimization for Video Compression,” in the IEEE Signal Processing Magazine, vol. 15, no. 6, pp. 74-90, Nov. 1998
[13]R. C. Gonzalez and R. E. Woods, “Digital image processing,” vol. 10, no. 2, pp. 585–611, 2001
[14]I. Choi, J. Lee, and B. Jeon, “Fast coding mode selection with rate distortion optimization for MPEG-4 part-10 AVC/H.264,” IEEE Trans. Circuits Syst. Video Technol., vol. 16, no. 12, pp. 1557-1561, June 2005
[15]U. Mithun, “An Early Intra Mode Skipping Technique for Inter Frame coding in H.264 BP”, in Proc. IEEE Int. Conf. Consumer Electronics, pp.1-2, Jan. 2007