Stmicroelectronics Asia Pacific Pte Limited

Yau Wai Lucas Hui

Hong Lye Oh

Sapna George

Jean-Michel Bard

A method and apparatus of encoding digital video according to the ISO/IEC MPEG standards (ISO/IEC 11172-2 MPEG-1 and ISO/IEC 13818-2 MPEG-2) using an adaptive motion estimator. A plurality of global motion vectors are derived from the motion vectors of a previous picture in a sequence, and the global motion vectors are analyzed to determine motion characteristics. The video encoding is arranged to enable switching among different types of local motion estimators based on the motion characteristics of the moving pictures sequence. This gives rise to a motion estimation algorithm that can adaptively change its search range, search area and block matching scheme to suit different types of moving sequences.

Adaptive motion estimator

A method and apparatus control bit rates used in a moving pictures encoder, such as an MPEG standard encoder. A sequence of moving pictures is divided into segments each of which comprises one or more groups of pictures. A constant overall bit rate is specified for the sequence of pictures, but variable bit rate encoding used within each segment. A difference between the number of bits allocated for encoding the segment and the actual bits used for encoding is determined, and the difference distributed over one or more subsequent segments.

Moving pictures encoding with constant overall bit-rate

A method and system for digital video noise reduction which includes a picture analyser () for analysing pictures in a video sequence to determine the amount of moving regions therein, a noise level detector () for estimating the noise level (N) in the video sequence, a filtering level estimator () for determining a maximum filtering level (L) for each picture based on the amount of moving regions and the estimated noise level (N) and a spatial filter () and a temporal filter (), the temporal filter being coupled to the filter level estimator for controlling the level of filtering of each picture in the sequence in accordance with the maximum filtering level.

Spatio-temporal video noise reduction system

A method and apparatus control bit rates used in a moving pictures encoder, such as an MPEG standard encoder. A sequence of moving pictures is divided into segments each of which comprises one or more groups of pictures. A constant overall bit rate is specified for the sequence of pictures, but variable bit rate encoding is used within each segment. A difference between the number of bits allocated for encoding the segment and the actual bits used for encoding is determined, and the difference is distributed over one or more subsequent segments.

Moving pictures encoding with constant overall bit rate

A method and apparatus for noise level estimation in a digital video signal, the apparatus including a pixel activity detector that produces a mean pixel activity level for each picture in the video signal, a contrast analyzer that produces a contrast activity level for each picture and a noise level calculator that is coupled to the activity detector and contrast analyzer to produce an estimated noise level by offsetting the contrast activity level from accumulated output of the activity detector.

Video signal noise level estimator

A method and apparatus for encoding pictures of a moving pictures sequence according to an overall target bit-rate, such as in a MPEG video encoder. Each picture has an assigned picture coding type for which a quality factor is adaptively determined according to past bit usages, so that bits can be adaptively allocated amongst picture types for optimizing visual quality of the encoded pictures.

Sequence adaptive bit allocation for pictures encoding

A method and apparatus of encoding digital video, for example according to the ISO/IEC MPEG standards (ISO/IEC 11172-2 MPEG-1 and ISO/IEC 13818-2 MPEG-2), which employs a local motion estimator for determining respective local motion vectors for groups of adjacent macroblocks in a picture. A local motion vector is determined for each row of macroblocks in a picture from the motion vectors of the macroblocks in that row. Then, for macroblocks in the corresponding row of a subsequently coded picture, the local motion vector can be used to select the search window used for determining the motion vectors. The local motion estimator improves search range and accuracy of macroblock motion vector detection without increasing the search window accessing bandwidth and caching requirement, and computation lode of searching.

Motion vector detection with local motion estimator

A method of processing video data to detect field characteristics of the data, including processing pixel values of the data to obtain differences between the values of two successive fields of the data, processing the difference values to detect interlace patterns in the successive fields, determining if the successive fields belong to a progressive frame based on detection of the interlace patterns, and generating a progressive frame output indicating that a progressive frame has been detected. The pixel values of the first field of the successive fields and a subsequent field to the successive fields are processed to obtain further difference values to determine if the subsequent field is a redundant field, when the progressive frame output is generated.

Progressive/interlace and redundant field detection for encoder

Conditional masking for video encoder

A method and apparatus for decoding a bitstream ( ) of transform coded multi-channel audio data. The bitstream is subjected to a block decoding process ( ) to obtain for each input audio channel within the multi-channel audio data a corresponding block of frequency coefficients ( ). Each block of frequency coefficients ( ) is assigned a higher precision inverse transform or a lower precision inverse transform according to predetermined characteristics of the audio data represented by the block. The blocks of frequency coefficients are subsequently subjected to the assigned transform ( ) and an output audio signal ( ) is generated in response to each of the higher and lower precision inverse transform processes.

Method and apparatus for decoding multi-channel audio data

A method and apparatus for decoding a multi-channel audio bitstream in which adaptive frequency domain downmixer (,) is used to downmix, according to long and shorter transform block length information (,), the decoded frequency coefficients of the multi-channel audio (,) such that the long and shorter transform block information is maintained separately within the mixed down left and right channels. In this way, the long and shorter transform block coefficients of the mixed down let and right channels can be inverse transformed adaptively (,) according to the long and shorter transform block information, and the results of the inverse transform of the long and short block of each the left and right channel added together (,) to form the total mixed down output of the left and right channel.

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Singapore, Singapore

Yau Wai Lucas Hui