Sigma Designs, Inc.

Altera Corporation

Omnivision Technologies, Inc.

Pts Corporation

Qpixel Technology, Inc.

Hitoshi Watanabe

Adityo Prakash

Edward R Ratner

Sachin Ahuja

David B Kita

Oliver W Shih

A motion-detection method includes for a motion-detection region in a first image of a scene, (i) determining a respective first pixel-value gradient at each of a plurality of pixel-coordinates within the motion-detection region, and (ii) determining a first feature-descriptor value as a function of the first pixel-value gradients and position vectors defined by the plurality of pixel-coordinates. The method also includes, for the motion-detection region in a second image of the scene, (i) determining a respective second pixel-value gradient at each of the plurality of pixel-coordinates, and (ii) determining a second feature-descriptor value as a function of the second pixel-value gradients and the position vectors. The method also includes determining a difference-parameter that varies in direct relationship to a difference between the first feature-descriptor value and the second feature-descriptor value.

Motion detection system and method

A video encoding method includes (i) determining a current bit rate of a communication channel between a destination device and a source device that stores an input video frame, and (ii) generating a current reconstructed frame and an encoded bitstream at least in part via inter-frame coding of a current input video frame of a sequence of input video frames using a previously-generated reconstructed frame generated at least in part via inter-frame coding of a previous input video frame. The current reconstructed frame is a compressed version of the current input video frame. When both (i) a subsequent bit rate, determined after said inter-frame coding, is less than a threshold and (ii) the current bit rate exceeds the threshold, the method includes: (a) generating a downscaled reconstructed frame at least in part by downscaling the current reconstructed frame; and (b) appending the encoded bitstream with a bit sequence representing the downscaled reconstructed frame.

Video coding device and method

A method for selecting a picture prediction mode from a candidate pool of picture prediction modes for video compression takes advantage of similarity in implementation between SKIP and DIRECT modes and one other inter-picture prediction modes, namely, the 16&#xd7;16 partition mode. The SKIP/DIRECT modes are considered if and only if the final prediction information of the 16&#xd7;16 partition mode, including motion vector, reference picture index, and prediction direction, is the same as that of the respective SKIP and/or DIRECT modes. The same motion prediction, reference picture index and prediction direction are used for the 16&#xd7;16 partition mode and the SKIP/DIRECT modes, and therefore, the same interpolation scheme can be used for both SKIP/DIRECT and 16&#xd7;16 partition modes.

Methods for efficient implementation of skip/direct modes in digital video compression algorithms

The approach of the present invention is to take advantage of similarity in implementation between SKIP and DIRECT modes and one other inter-picture prediction modes, namely, the 16&#xd7;16 partition mode. The SKIP/DIRECT modes are classified into two groups, one involving inter-picture prediction in one temporal direction in which prediction is chosen from either past or future recon pictures, and the other involving prediction in two temporal directions in which prediction is constructed as a superposition of both past and future recon pictures. The first group requires interpolation for only one direction, whereas the latter requires interpolation for both directions, thus requiring roughly twice as much data processing power than the first group. The 16&#xd7;16 partition mode also allows both prediction schemes, either past or future, or a superposition of past and future. The SKIP/DIRECT and 16&#xd7;16 partition modes all apply the same motion vector on the entire block unit. Methods of the present invention consider the SKIP/DIRECT modes if and only if the final prediction information of the 16&#xd7;16 partition mode, including motion vector, reference picture index, and prediction direction, is the same as that of the respective SKIP and/or DIRECT modes. The point here is that the same motion prediction, reference picture index and prediction direction are used for the 16&#xd7;16 partition mode and the SKIP/DIRECT modes, and therefore, the same interpolation scheme can be used for both SKIP/DIRECT and 16&#xd7;16 partition modes, thus saving computational cost as well as implementation cost.

The present invention provides a framework for the processing of blocks between two data frames and in particular application to motion estimation calculations in which a balance among the performance of a motion search algorithm, the size of on-chip memory to store the reference data, and the required data transfer bandwidth between on-chip and external memory can be optimized in a scalable manner, such that the total system cost with hierarchical embedded memory structure can be optimized in a flexible manner. The scope of the present invention is not limited to digital video encoding in which motion vector is part of information to be encoded, but is applicable to any other implementation in which difference between any two data frames are to be computed.

Methods for processing two data frames with scalable data utilization

The presently preferred methods of the present invention take advantage of the syntax structure of H.264 and adaptively switch the entropy coding mode between CABAC and CAVLC. In those profiles of H.264 where CABAC is supported such as the Main profile and the High profiles (HP, Hi10, Hi422, Hi444), the entropy coding mode to be used is specified via a picture parameter set ('PPS'), where a particular PPS is specified for each slice in its header ('slice header'). The encoders of the present invention provide a multiple-PPS for both the CAVLC and CABAC, so that bitstreams are produced by both CAVLC and CABAC. CAVLC, having a simpler algorithm structure, is implemented as a part of the video pipe, where each single video pipe stage is designed to operate within a pre-defined number of clock cycles. The video pipe generates SE at pre-scheduled instances buffered in FIFO. The SE serves as input to CABAC, where CABAC encodes the SE in an event-driven fashion. During this process, CABAC is monitored to determine if the CABAC engine is able to keep up with the video pipe. The video pipe, implemented using CAVLC, by design will complete the encoding process within the allotted time. However, CABAC, although having better encoding efficiency and where its generated output is more desirable, its encoding completion time is uncertain and may require more time than it is allowed. Thus if CABAC cannot complete the encoding process within the allotted time, the bitstream generated by CABAC would not be complete and it cannot be used. If CABAC can complete the encoding process within the allotted time, the CABAC engine would be allowed to complete the encoding process and its generated output would be used as the bitstream of choice.

Methods for adaptively selecting entropy encoding modes

One embodiment relates to an apparatus for image processing. The apparatus includes a candidate edge chain identifier for identifying candidate edge chains in an image being processed, means for calculating a dynamic chain-based threshold function that is dependent on at least one characteristic of the image being processed, and a threshold applicator for applying the dynamic chain-based threshold function to the candidate edge chains. The characteristic of the image being processed may be global in that it is determined from the overall image being processed. A system may include an encoder or a decoder, both of which include the above apparatus. Another embodiment relates to a method for image processing. The method determines a dynamic chain-based threshold function that is dependent on at least one characteristic of the image being processed and applies the dynamic threshold to a candidate edge chain.

Dynamic chain-based thresholding using global characteristics

A method of reconstructing a previously occluded area of a video image frame exposed by the motion of a segment within said image frame. In one embodiment the method involves approximating the color values of the pixels in the newly exposed area from the color values of the neighboring image segments. The process is refined by identifying a set of neighboring segments to the exposed area, called fill segments, that most closely resemble the color values of the pixels within the exposed area. These fill segments are then used to reconstruct the color values of the exposed area. In one embodiment, the identities of the fill segments are transmitted to an exemplary decoder.

Method of filling exposed areas in digital images

One embodiment relates to an apparatus for image processing. The apparatus includes a candidate edge chain identifier for identifying candidate edge chains in an image being processed, means for calculating a dynamic chain-based threshold function that is dependent on at least one characteristic of the image being processed, and a threshold applicator for applying the dynamic chain-based threshold function to the candidate edge chains. The characteristic of the image being processed may be local in that it is calculated from the vicinity of each candidate chain. A system may include an encoder or a decoder, both of which include the above apparatus. Another embodiment relates to a method for image processing. The method determines a dynamic chain-based threshold function that is dependent on at least one characteristic of the image being processed and applies the dynamic threshold to a candidate edge chain.

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San Jose, CA, United States of America

Hitoshi Watanabe