The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 21, 2001
Filed:
Mar. 19, 1998
Nader Mohsenian, Endicott, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A real-time single pass variable bit rate control strategy is provided to achieve variable bit rate (VBR) MPEG-2 encoding in a video compression system. For a sequence of frames, the level of encoding difficulty of a video interval (i.e., a group of pictures (GOP)) is determined by a perceptual rate-quantization ({overscore (C)}-{overscore (Q)}) model. This model assigns a composite ({overscore (C)}-{overscore (Q)}) curve to each video interval from which the number of bits for the video interval is estimated. The estimation relies on a causal predictive model using the parameters obtained from previously encoded video intervals. The R-Q relationship of each picture type is updated and picture bits are assigned, based on the total rate of the video interval under analysis. Robustness of the variable bit rate control strategy is ensured throughout scene transitions and instabilities by applying, for example, a non-linear median filter, and a low pass filter, respectively.