Google Inc.

Tektronix, Inc.

Arris Enterprises LLC

Other

Tut Systems, Inc.

Peter A Borgwardt

Mayer D Schwartz

Shiv Saxena

Brenda Van Veldhuisen

Charles H Van Dusen

Guoyao Yu

Sean Thomas McCarthy

Vijay Kamarshi

Terry J Ligocki

Caspar Horne

Sean T Mccarthy

A dual-pass rate control video encoder including a first pass encoder module configured to receive uncompressed input video including a sequence of pictures, the input video including a plurality of contiguous sequences of pictures each referred to as a Group of Pictures (GOP) that, when coded, begin with an I-picture in display order and end with a last picture before a next I-picture, detect scene changes within the input video. The dual-pass rate control video encoder including a second pass encoder module configured to receive the uncompressed input video via a delay unit.

Apparatus for dual pass rate control video encoding

A video processing system is provided to create quantization data parameters based on human eye attraction to provide to an encoder to enable the encoder to compress data taking into account the human perceptual guidance. The system includes a perceptual video processor (PVP) to generate a perceptual significance pixel map for data to be input to the encoder. Companding is provided to reduce the pixel values to values ranging from zero to one, and decimation is performed to match the pixel values to a spatial resolution of quantization parameter values (QP) values in a look up table (LUT). The LUT table values then provide the metadata to provide to the encoder to enable compression of the original picture to be performed by the encoder in a manner so that bits are allocated to pixels in a macroblock according to the predictions of eye tracking.

Method of bit allocation for image and video compression using perceptual guidance

A method of dual-pass rate control video encoding and an encoder are disclosed. Uncompressed input video is received with a video encoder. First pass encoding is performed, and a second pass encoding is performed with the video encoder at a delay relative to the first pass. The first pass encoding detects scene changes within the input video, assigns macroblocks to a pre-determined number of activity classes, and determines a complexity of each picture within the sequence of pictures. Information from the first pass encoding concerning the scene changes, the activity classes, and the complexity are used for rate control determined in second pass encoding for producing and outputting a bit stream of compressed video. During at least one of the first pass and second pass encoding, boundaries of at least some of the GOPs are adjusted to be aligned with the scene changes.

Method for dual pass rate control video encoding

A method of operating a multi-processor video encoder by determining a target size corresponding to a preferred number of bits to be used when creating an encoded version of a picture in a group of sequential pictures making up a video sequence. The method includes the steps of calculating a first degree of fullness of a coded picture buffer at a first time, operating on the first degree of fullness to return an estimated second degree of fullness of the coded picture buffer at a second time, and operating on the second degree of fullness to return an initial target sized for the picture. The first time corresponds to the most recent time an accurate degree of fullness of the coded picture buffer can be calculated and the second time occurs after the first time.

Parallel rate control for digital video encoder with multi-processor architecture and picture-based look-ahead window

An algorithm for distributing video buffer rate control over a parallel compression architecture uses parallel processors to first compute complexity measures for each macroblock of a current picture. Based upon the complexity measures a master controller determines target rates for each slice of the current picture. A set of slices are then encoded in parallel by the parallel processors acting as microrate controllers, each slice being encoded based solely upon its own target rate. After the set of slices are encoded, the target rates are adjusted for the remaining slices based upon the actual rates from the encoded slices, and the next set of slices is encoded in parallel based upon the updated target rates. After each macroblock within a slice is encoded, a VBV fullness check is made to detect if VBV overflow or underflow is likely to occur. In such an event emergency action is taken to prevent such overflow or underflow. In this manner message passing overhead between the master controller and parallel processors is minimized while retaining the benefits of parallel processing.

Distributing video buffer rate control over a parallel compression

Motion estimation using limited-time early exit with prequalification matrices and a predicted search center reduces computational time for a video compression encoder. The partial absolute error obtained for a given location within a search area is compared periodically with a prior absolute error obtained for a prior position within the search area to determine whether the partial absolute error is greater than such prior absolute error. If the partial absolute error is greater, then the processing for that position may be terminated and the search moved to the next location within the search area. Using the triangle inequality a series of prequalification matrices are generated for the reference image and for the current image being searched. Comparing the prequalification matrices using early exit further reduces the computational time. Also by using a motion vector for a neighboring block of pixels to determine a predicted center point within the search area, one of the first few locations within the search area generally produces the best difference, so that all subsequent locations result in early exit, reducing computational time even further. Finally to assure that the motion vectors for a frame are determined within realtime constraints, the amount of time required to process a block as measured in terms of a number of AbsSum8 operations is used to terminate the processing of a block if the processing has not yet produced a final absolute error minimum. For those blocks which complete early, the saved 'time' is averaged over the remaining blocks.

Motion estimation using limited-time early exit with prequalification

A method and an apparatus render on a display screen (14) an image of a three-dimensional object. The object is represented by image data arranged in a constructive solid geometry format including at least one halfspace that divides an object space (28) into an interior region that lies inside the halfspace and an exterior region that lies outside the halfspace. The boundary of the halfspace is defined by an implicit mathematical function. The method includes subdividing the object space into volume elements of either a cubical or rectangular parallelepiped shape. For each volume element, an upper bound and a lower bound are calculated to the values of each function defining the boundary of a halfspace. In a first preferred embodiment, the calculation of the upper and lower bounds of the function defining a halfspace within a volume element identifies all of the extrema of the function that lie in or on the boundary of the volume element. In a second preferred embodiment, the upper and lower bounds are calculated as approximations to the absolute maximum and minimum values, respectively, of the function. An image is rendered in accordance with whether the upper and lower bounds of the function defining the boundary of a halfspace show that all locations in a volume element are inside or outside the halfspace.

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Portland, OR, United States of America

Peter A Borgwardt