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姓名 邱建勛(Chien-Hsun Chiu) 查詢紙本館藏 畢業系所 通訊工程學系 論文名稱 運用主觀品質量測之視訊編碼畫面率最佳化機制
(Frame Rate Optimization of Video Encoding Using Subjective Quality Metric)相關論文 檔案 [Endnote RIS 格式]
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摘要(中) 視訊壓縮編碼、網路以及儲存能力的發展,使得多媒體系統的應用越來越普及與廣泛,但在頻寬的限制下讓使用者得到最好的影像品質仍一直是影像編碼的重要課題。通常,我們會使用降低畫面率或提升量化參數的方法來降低位元率。傳統的影像編碼方法通常使用非主觀品質量測如PSNR來進行評估,但在畫面率變動的狀況下,非主觀視覺品質量測無法表現出人眼所感受的影像品質。因此,使用一合適的主觀品質量測對於找出影像編碼時的最佳參數設定是必須的
在本論文中,我們的目的是找出在不同位元率下,影像的畫面率該如何設定才能產生出最佳的主觀品質量測。我們首先定義數個能反映影像本身於時間、空間上特性的參數,然後找出影像的主觀視覺品質量測與特性參數的關係式。最後,我們將提出一在影像編碼中運用此關係式以達到畫面率最佳化的演算法。
實驗結果顯示,在頻寬不足的狀況下,降低畫面率有時的確可得到比只提升量化參數還優秀的視覺品質。而演算法預測的最佳畫面率也與實際的最佳畫面率相當接近。
摘要(英) With the improvements of video coding technology, network infra-structures, storage capacity, and CPU computing capability, the applications of multimedia systems become wider and more popular. Nowadays, how to provide the best video quality to users under the rate constraints is always an important issue in video coding. In general, we can either increase the quantization step size or reduce the frame rate to meet the bitrate constraint. Objective quality metrics such as PSNR has long been used as the quality assessment in video coding. However, in the condition of video frame rate switching, this objective quality metric is not able to reveal the perception of human eyes. Instead, a good subjective video quality metric is necessary in helping us find the best encoding configurations.
In this work we focus on how to find the optimum frame rates in the sense of maximizing a subjective video quality metric under different rate constraints. We first characterize video sequences by parameters in temporal and spatial aspects such as edge strength, average motion vector, and motion compensation difference. Then the subjective video quality metric of a video sequence is modeled by these characteristic parameters. Finally, with this model a frame rate optimization algorithm in video encoding is proposed.
Simulation results show that reducing frame rate may be more effective than increasing quantization step size when the given bitrate is not sufficiently high. It also reveals that the frame rate provided by the proposed algorithm is very close to the ideal case.
關鍵字(中) ★ 主觀視覺
★ 位元率限制
★ 畫面率最佳化關鍵字(英) ★ rate constraint
★ subjective quality
★ frame rate optimization論文目次 第1章 緒論 1
1.1 研究背景 1
1.2 研究動機與目的 2
1.3 論文架構 4
第2章 H.264影像編碼介紹 5
2.1 H.264影像編碼標準簡介 5
2.2 H.264架構介紹 7
2.3 網路提取層 8
2.4 影像編碼層 8
2.4.1 空間性預測 (Intra Prediction) 8
2.4.2 時間性預測 (Inter Prediction) 11
2.4.3 轉換 (Transform) 14
2.4.4 量化 (Quantization) 16
2.4.5 去區塊濾波器 (Deblocking Filter) 17
2.4.6 熵編碼 (Entropy Coding) 18
第3章 主觀視覺品質量測介紹 20
3.1 客觀、主觀視覺品質量測與其特性 20
3.1.1 客觀視覺品質量測的計算 20
3.1.2 主觀視覺品質的實驗 21
3.1.3 主觀視覺品質量測 (Subjective Video Quality Metric) 22
3.2 影像編碼中的主觀視覺品質量測工具介紹:QM 26
第4章 應用於即時影像編碼的的畫面率最佳化機制 30
4.1 H.264編碼中主觀視覺量測(QM)、位元率與畫面率之關係分析 31
4.2 影像特性之參數介紹 42
4.2.1 影像的時間複雜度參數 42
4.2.2 影像的空間複雜度參數 43
4.2.3 影像的殘餘值(Residual)資料量參數 47
4.3 H.264編碼中主觀視覺品質關係式參數與影像特性參數之關係分析 49
4.4 H.264編碼中主觀視覺量測(QM) 、位元率、畫面率與影像特性參數之關係式 54
4.5 運用於即時影像編碼之畫面率最佳化機制 55
第5章 實驗結果 57
5.1 實驗參數環境 57
5.2 最佳畫面率之預測與分析 59
5.2.1 最佳畫面率之分析比較 59
5.2.2 最佳畫面率所產生之主觀視覺量測之分析比較 63
第6章 結論與未來展望 67
參考文獻 69
參考文獻 [1] Advanced Video Coding for Generic Audiovisual Services, ITU-T Rec. H.264 and ISO/IEC 14496-10 (MPEG-4 AVC), ITU-T and ISO/IEC JTC 1, Version 1: May 2003, Version 2: May 2004, Version 3: Mar. 2005, Version 4: Sept. 2005, Version 5 and Version 6: June 2006, Version 7: Apr. 2007, Version 8 (including SVC extension): Consented in July 2007.
[2] ITU-R BT.500 “Methodology for the Subjective Assessment of the Quality for Television Pictures”, ITU-R Std., Rev. 11, June 2002.
[3] ITU-T Rec. P.910, “Subjective video quality assessment methods for multimedia applications, ” Sept. 1999.
[4] D. Wang, F. Speranza, A. Vincent, T. Martin, and P. Blanchfield, “Towards optimal rate control: a study of the impact of spatial resolution, frame rate, and quantization on subjective Video quality and bit rate,” in Proceedings of Visual Communications and Image Processing 2003, Lugano, Switzerland, July 8–11, 2003, pp. 198–209.
[5] S. Winkler, “A perceptual distortion metric for digital color video”, in Proc. SPIE, VOL. 3644, May 1999, pp.175-184.
[6] J. Lubin, and D. Fibush, “Sarnoff JND vision model”, T1A1.5Working group Document, T1 Standards Committee, 1997.
[7] A.B. Watson, J. Hu, and J.F. McGowan III, “Digital video quality metric based on human vision”,Journal of Electronic imaging, VOL. 10, NO. 1, Jan 2001, pp. 20-29.
[8] Z. Wang, and A.C. Bovik, “A universal image quality index”, IEEE Signal Processing Letters, VOL. 9, NO. 3, Mar. 2002, pp. 81-84.
[9] R. Feghali, D. Wang, F. Speranza, and A. Vincent, “Quality metric for video sequences with temporal scalability,” in Proc. of ICIP, vol. 3, Sep. 2005, pp. III–137–40.
[10] R. Feghali, F. Speranza, D. Wang, and A. Vincent, “Video quality metric for bit rate control via joint adjustment of quantization and frame rate,” IEEE Trans. on Broadcasting, VOL. 53, NO. 1, pp. 441–446, Mar. 2007.
[11] H.-T. Quan and M. Ghanbari, “Temporal Aspect of Perceived Quality of Mobile Video Broadcasting,” IEEE Trans. on Broadcasting, vol. 54, no. 3, pp. 641–651, Sept. 2008.
[12] C. S. Kim, S. H. Jin, D. J. Seo, and Y. M. Ro, "Measuring Video Quality on Full Scalability of H.264/AVC Scalable Video Coding," IEICE Trans. on Communications, vol. E91-B, no. 5, pp. 1269-1278, 2008.
[13] X. Ran, and N. Farvardin, “A perceptually motivated three component image model – Part 1: Description of the model”, IEEE Trans.On Image Processing, Vol.4(4), 1995, pp.401- 415
[14] A. Bhat, I. Richardson and S. Kannangara,” A new percetual quality metric for compressed video,” ICASSP, vol.51, no.3, pp. 933- 936, 2009.
[15] Y. Ou, T. Liu, Z. Zhao, Z. Ma and Y. Wang, “Modeling the impact of frame rate on perceptual quality of video,” IEEE ICIP 2008, San Diego, Oct. 2008, pp. 689–692.
[16] Y. Wang, Z. Ma, and Y. Ou, “Modeling rate and perceptual quality of scalable video as functions of quantization and frame rate and its application in scalable video adaptation,” in Proc. of IEEE International Packet Video Workshop, Seattle, WA, May 2009.
[17] E. Ong, X. Yang, W. Lin, Z. Lu, and S. Yao, “Perceptual Quality Metric For Compressed Videos,” in Proc. of ICASSP, vol. 2, Mar. 2005, pp. 581–584.
[18] E. Ong, W. Lin, Z. Lu, S. Yao, and M. Loke, "Perceptual Quality Metric for H.264 Low Bit Rate Videos," IEEE International Conference on Multimedia and Expo, vol., no.,pp.677-680, July 2006.
[19] H.-T. Quan and M. Ghanbari, “Temporal Aspect of Perceived Quality of Mobile Video Broadcasting,” IEEE Trans. on Broadcasting, vol. 54, no. 3, pp. 641–651, Sept. 2008.
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