Method and apparatus for improved coding mode selection

Abstract

In this disclosure, a novel method for direct mode enhancement in B-pictures and skip mode enhancement in P-pictures in the framework of H.264 (MPEG-4 / Part 10) is disclosed. Direct mode and skip mode enhancements are achieved by clustering the values of the Lagrangian, removing outliers and specifying smaller values of the Lagrangian multiplier in the rate-distortion optimization for encoding mode selection. Experimental results using high quality video sequences show that bit rate reduction is obtained using the method of the present invention, at the expense of a slight loss in peak signal-to-noise ratio (PSNR). By conducting two different experiments, it has been verified that no subjective visual loss is visible despite the peak signal-to-noise ratio change. In relationship to the existing ratedistortion optimization methods currently employed in the (non-normative) MPEG4 / Part 10 encoder, the method of the present invention represents a simple and useful add-on. More importantly, when other solutions such as further increasing the values of the quantization parameter are not applicable, as inadmissible artifacts would be introduced in the decoded pictures, the method of the present invention achieves bit rate reduction without introducing visible distortion in the decoded sequences. Even more, despite the fact that the present document makes use of the H.264 framework, the proposed method is applicable in any video encoding system that employs ratedistortion optimization for encoding mode selection.

Description

[0001] related application [0002] This patent application claims priority to US Provisional Patent Application Serial No. 60 / 439062, published on January 8, 2003, entitled "METHOD AND APPARATUS FOR IMPROVED CODING MODE SELECTION". technical field [0003] The invention relates to the field of multimedia compression systems. In particular, the present invention discloses methods and systems for improved coding mode selection. Background technique [0004] Digital-based electronic media formats are finally replacing analog electronic media formats on a large scale. Digital compact discs (CDs) replaced analog vinyl records a long time ago. Analog tapes are becoming increasingly rare. Second and third generation digital audio systems, such as minidisc and MP3 (MPEG Audio Layer 3) are taking market share from the first generation digital audio compact disc format. [0005] However, the video medium has evolved more slowly than audio into digital storage and transmission for...

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Problems solved by technology

[0005] However, the video medium has evolved more slowly than audio into digital storage and transmission formats

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