Arbitrarily Shaped Object Coding based on H.264/AVC

[Abstract] [Experimental Results]   [References]   [PDF]


    Recent video coding research gives birth  to the latest video coding standard H.264/AVC whose compression performance significantly exceeds previous standards with more than 50%. But as compared with the MPEG-4, the capability of coding arbitrarily shaped objects is absent from the latest standard. In this paper, we propose a new arbitrarily shaped object coding codec including encoder and decoder based on the latest H.264/AVC, which adopts improved binary alpha coding with a novel motion estimation to facilitate the binary alpha blocks prediction and in the texture coding, a new arbitrarily shaped integer transform derivative from 4x4 ICT in H.264 to code texture and associated coding techniques. Extension in High Definition sequences and subjective evaluations are made.  Experimental results prove the coding efficiency and flexibility of our proposal and the potential applications are demonstrated.

Experimental Results (Compressed by JPEG)

(a) the block diagram of encoder

(b) the block diagram of decoder

Fig.1 the block diagrams of object coding codec.

Fig.2 Three types Macroblocks .

Fig.3 the performance of object coding in CIF and QCIF.

Fig.4  the performance of object coding in HD.



No matter what the resolution is, the result of object coding only can approach to the performance of H.264 but do not win or even equal to it in terms of the traditional measurement (PSNR).


Subjective test:

n     Under the test condition[9] including: ØObservers requirement,  Ø Viewing condition,Ø Test sequence selection criteria, ØAssessment Procedure, ØStatistical quantitative analysis on observer's result. Two sequences (good and bad) are shown firstly as references, and then sequences with different QPs, including the original sequence, are displayed randomly. Let the observers mark (1~5 points) for these sequences in above conditions.

After error elimination and normalization (1~5 points) referred to the original sequence, 18 sets of subjective test results are sampled. The results are listed in following figures.

Fig.5 Subjective test result of CIF sequences.

Fig.5 Subjective test result of HD sequences.

  • Two methods have comparable performance
  • And, we can see that object coding works better than H.264 at low quality (PSNR<35dB) for HD
  • nF/B used different QPs, and keep a good shape information in the low bit-rate


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[2]     T. Wiegand, G. Sullivan, G. Bjontegaard and A. Luthra, "Overview of the H.264 /AVC Video Coding Standard," IEEE Transactions on Circuits and Systems for Video Technology, Vol. 13, No. 7, pp. 560- 576, July 2003.

[3]     H. Schwarz, D. Marpe and T. Wiegand, "Overview of the Scalable Video Coding Extension of the H.264/AVC Standard," IEEE Trans. on Circuits and Systems for Video Technology, vol. 17, no. 9, pp. 1103-1120, Sept. 2007.

[4]     N. Brady," MPEG-4 Standardized Methods for the Compression of Arbitrarily Shaped Video Objects," IEEE Trans. CSVT, VOL 9, pp. 1170-1189,  Dec. 1999.

[5]     T. Sikora and B. Makai, "Shape-adaptive DCT for generic coding of video," IEEE Trans. on Circuits and Systems for Video Technology, vol. 5, no. 1, pp. 59-62, Feb. 1995

[6]     X. Li, E. Edirisinghe and H.Bez, "Shape adaptive integer transform for coding arbitrarily shaped objects in H.264/AVC," VCIP 2006, Vol. 6077, C1-C10, Jan. 2006.

[7]     A. A. Alatan, L. Onural, M. Wollborn, R. Mech, E. Tuncel, and T. Sikora, "Image sequence analysis for emerging interactive multimedia services-The European COST 211 framework," IEEE Trans. Circuits Syst. Video Technol., vol. 8, no. 11, pp. 802-813, Nov. 1998.

[8]     R. Koenen, "MPEG-4 overview ISO/IEC JTC/SC29/WG11 Coding of Moving Pictures and Audio N4030," Mar. 2001.

[9]  VQEG HDTV Group Test Plan, Draft Version 3.0 (Final), 2009


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