Nippon Telegraph and Telephone Corporation

Naoki Ono

Atsushi Shimizu

Masaki Kitahara

Seisuke Kyochi

Ken Nakamura

Tokinobu Mitasaki

Kazuto Kamikura

An image encoding method that encodes an image so as to optimize estimated values of processing units which are a coding unit, a prediction unit, and a transform unit by selecting sizes of the individual processing units. The method includes a division step that divides an image having a size of the coding unit into a plurality of blocks; an activity computation step that computes activities pertaining to the individual blocks; and a transform unit size determination step that determines, based on the computed activities, a size pattern of the transform unit within the image having the size of the coding unit.

Image encoding apparatus and method, and image encoding program

In an intra-picture, a predetermined region is set as a normal encoding region, and a region other than the predetermined region is set as a simplified encoding region. In a subsequent picture, the normal encoding region is set as a larger region including a normal encoding region of a previous picture, and a region other than the normal encoding region is set as a simplified encoding region. In each picture, normal encoding is performed on a block of the normal encoding region, and simplified encoding in which a generated code amount and a computation amount are smaller than in the normal encoding is performed on a block of the simplified encoding region.

Video encoding method using at least two encoding methods, device and computer program

A quantization control apparatus provided in a video encoding apparatus which utilizes intra slices. The quantization control apparatus includes a similarity computation device that computes similarity between an intra slice region of an encoding target picture and an intra slice region of each of previously-encoded pictures, where the similarity is an index determined such that the closer the images of the two different intra slices, the higher the similarity; a picture selection device that selects a picture having the highest similarity from among the previously-encoded pictures, based on the similarity computed by the similarity computation device; and a quantization step determination device that determines a quantization step used for encoding the encoding target picture, based on encoding information for the picture selected by the picture selection device.

Quantization control apparatus and method, and quantization control program

An object is to suppress an instantaneous increase in the computational complexity of an encoder and an information amount of an encoding result without increasing a delay even when input timing of input video is not constant and fluctuates. A frame rate control method for adjusting a frame rate of input video to a frame rate at which an encoder is able to perform encoding includes: a step of determining whether the number of pictures input in the past within a predetermined time from a time when a determination target picture of dropping is input exceeds a predetermined threshold value; and a step of discarding the determination target picture if the number of pictures exceeds the threshold value and designating the determination target picture as an encoding target if the number of pictures does not exceed the threshold value.

Frame rate control method and apparatus for encoding image based on threshold value

A video encoding device, which uses intra encoding and inter encoding with motion compensation with respect to an input video signal, includes a determination unit which determines whether the input video signal to be encoded corresponds to a stationary region, a region having minute motion, or a region having normal motion, a first encoding unit which performs inter encoding of a motion vector (0, 0) with respect to a region determined as a stationary region by the determination unit, a second encoding unit which performs motion search and inter encoding in a limited search range with respect to a region determined as a region having minute motion by the determination unit, and a third encoding unit which performs motion search and inter encoding in a normal search range with respect to a region determined as a region having normal motion by the determination unit.

Video encoding device, video encoding method and video encoding program

A video encoding control method for controlling encoding of an input video signal. The method includes the steps of detecting an underflow of a decoder buffer; if the underflow of the decoder buffer has been detected, suppressing an amount of generated code by skipping an encoding target picture or by encoding the encoding target picture so as to produce a minimum amount of generated code; after suppressing the amount of generated code, comparing a current rate of occupancy in the decoder buffer with a predetermined threshold for the rate of occupancy in the decoder buffer; and performing a control for continuously suppressing the amount of code generated for each encoding target image by using the above step of suppressing the amount of generated code until the rate of occupancy in the decoder buffer exceeds the threshold based on a result of the above comparison.

Video encoding control method and apparatus

In a video encoding control method of the present invention, each picture is encoded in units of encoding-order picture groups such as GOPs, and when CPB underflow has occurred, an encoding parameter such as a quantization parameter and filter strength of a pre-filter is changed in such a manner that a generated bit rate is reduced, and an encoding-order picture group that is being encoded is re-encoded from its first picture using the changed encoding parameter.

Video encoding control method, video encoding apparatus and video encoding program

A video encoding control method encodes an input video signal by controlling a generated bit rate so a hypothetical buffer in a decoder does not overflow or underflow includes: sequentially encoding each picture in an encoding-order picture group in accordance with a predetermined encoding parameter, the encoding-order picture group including a predetermined number of pictures and being a collection of successive pictures in the order of encoding; calculating a quantization statistic of each picture based on quantization parameter information used to encode each picture each time each picture is encoded, and checking whether the quantization statistic exceeds a predetermined threshold value, and if the quantization statistic exceeds the predetermined threshold value, changing the encoding parameter so the generated bit rate resulting from encoding is reduced and performing re-encoding from a first picture of an encoding-order picture group that is being encoded using the changed encoding parameter.

Video encoding control method, video encoding apparatus, and video encoding program

A code amount control method used in a video encoding method for performing code amount control by estimating a generated code amount for an encoding target picture. The control method includes steps of computing a feature value of the encoding target picture and stores the value into a storage device; extracting a feature value of a previously-encoded picture stored in the storage device and used for generated code amount estimation; comparing the feature values of the encoding target picture and the previously-encoded picture; and a step performed according to a result of the comparison. If it is determined that difference between both feature values is larger than a predetermined criterion value, the amount of code generated for the encoding target picture is estimated using no result of encoding of the previously-encoded picture, and otherwise the relevant generated code amount is estimated based on a result of the encoding.

Code amount control method and apparatus

A video processing method includes dividing a processing target image, which forms a video image, into a plurality of divided areas; determining a bandwidth applied to the divided areas; computing a filter coefficient array for implementing frequency characteristics corresponding to a band limitation using the bandwidth; subjecting the image data to a filtering process using the filter coefficient array; deriving a value of error information between the obtained data and the original image data, and computing an allocation coefficient used for determining an optimum bandwidth, based on the derived value; determining, for each divided area, the optimum bandwidth corresponding to the allocation coefficient, and computing an optimum filter coefficient array for implementing the frequency characteristics corresponding to a band limitation using the optimum bandwidth; subjecting the image data of the divided area to a filtering process using the optimum filter coefficient array; and synthesizing the obtained data of each divided area.

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Yokosuka, Japan

Naoki Ono