Abstract: The present invention is a method and system for reducing and potentially eliminating the number of packets dropped during 802.11 handoff by an old access point (AP) to a new AP in a wireless local area network (WLAN) which thereby also reduces the impact of retransmission on network throughput. With the present invention, once a mobile station has successfully re-associated with a new AP, the new AP can fetch those packets which arrived at the old AP during handoff and forward them to the mobile station. The method and system of the present invention thus reduces both total packet drop and retransmission impact on network throughput by enabling direct recovery of packets received during handoff by the old AP from the old AP.

Abstract: A complexity scalable decoder system and method. The system comprises: a decoder having a plurality of functional blocks for decoding compressed video data, the decoder further includes a plurality of scalable functions for selectively reducing a complexity of at least one of the functional blocks; and a local resource controller for generating a scaling strategy for the decoder, wherein the scaling strategy is selected in response to a complexity requirement received from a system resource manager, and wherein the scaling strategy is selected from a plurality of predetermined scaling strategies available to the local resource controller. Each of the predetermined scaling strategies may be selected from a look-up table designed off-line.

Abstract: A video processing system comprising: a decoder having a complexity reduction system; and a post-processing system for processing an output of the decoder, wherein the post-processing system includes a filter for intentionally blurring a set of frames in a group of pictures (GOP) to achieve a smooth visual transition between frames.

Abstract: A system and method for scaling an MPEG-2 video decoder subject to a resource constraint. A decoder system is provided for decoding compressed video data arranged in a group of pictures, wherein the group of pictures include I pictures, P pictures and B pictures. The system comprises a processing path for decoding an error residual associated with the group of pictures, and a filtering system for preventing the error residual associated with B pictures from being decoded by the processing path. The decoder system may further comprise a system for selectively enabling the filtering system for B pictures having a DC coefficient that is below a predetermined threshold.

Abstract: A method and system of reducing the computation load of an MPEG decoder by changing the encoding algorithms in a video-processing system are provided. During an encoding mode, a stream of data blocks is received and at least one motion vector and one motion compensation prediction value for each macro-block are generated. The prediction value is transformed into a set of DCT coefficients. Prior to the quantizing step, the set of DCT coefficients are modified according to predetermined criteria. To this end, the total energy level of the DCT coefficients excluding the lowest 2×2 DCT coefficients is computed, and last column and last row of the DCT coefficients is discarded alternatively until the total energy level of the DCT coefficients reaches a predetermined energy level. Therafter, the discarded column or row is assigned to a predetermined value.

Abstract: A system and method for scaling an MPEG-2 video decoder subject to a resource constraint. A decoder system is provided for decoding compressed video data arranged in a group of pictures, wherein the group of pictures include I pictures, P pictures and B pictures. The system comprises a processing path for decoding an error residual associated with the group of pictures, and a filtering system for preventing the error residual associated with B pictures from being decoded by the processing path. The decoder system may further comprise a system for selectively enabling the filtering system for B pictures having a DC coefficient that is below a predetermined threshold.

Abstract: The present invention provides a method of and system for determining whether a local area of a compressed video stream represented by a plurality of DCT encoded blocks subject to decoding and filtering/scaling is a stationary area or an interlaced moving area. Further, given such information, the invention relates to dynamically switching between frame- or field-based operations in a smart way, thus optimizing the output picture quality. Also, a DCT-domain-filtering scheme for field-based filtering/scaling of frame-DCT data is provided herein.

Abstract: A method and system of regulating the computation load of an MPEG encoder in a video processing system are provided. A stream of data blocks is received and buffered temporarily for subsequent retrieval during an encoding mode. The buffered data block is then retrieved from the buffer for an encoding operation in accordance with a conventional encoding method. Meanwhile, the fullness level of the buffer is monitored to determine an appropriate encoding complexity for a subsequent encoding process. To this end, a predetermine threshold range is compared to the fullness level so that the subsequent encoding operation can be performed at an improved buffer efficiency.

Abstract: A system and method that reduces computational complexity of a decoder by identifying a skippable region in an overlaid area. The invention provides a system for processing encoded video data, comprising: an analysis system that determines if a current video frame having an overlaid area acts as a reference for future video frames; and a system for identifying a skippable region in the overlaid area. The invention may also include a system for identifying a portion of the overlaid area as the skippable based on analysis of motion vectors or motion vector ranges.

Abstract: The present invention is directed to method of scaling interlaced video. According to the present invention, the method includes an interlaced video frame being divided into blocks. Determining if any of the blocks correspond to a moving area in the interlaced video frame. Field-based scaling is performed on blocks corresponding to a moving area. Frame-based scaling is performed on blocks not corresponding to a moving area.

Abstract: The present invention is directed to reduced B-frame decoding. According to the present invention, the number of transform coefficients in B-frames are reduced to produce reduced B-frames. Also, inverse scanning and inverse quantization is performed on the reduced B-frames. Further, an inverse transform is performed on the reduced B-frames. In one embodiment of the present invention, the reduced B-frames are produced by identifying blocks associated with the B-frames and selecting transform coefficients included in a predetermined area of the identified blocks.

Abstract: The present invention is directed to decoding a video bitstream at a first resolution where embedded resizing is used in conjunction with external scaling in order to reduce the computational complexity of the decoding. According to the present invention, residual error frames are produced at a second lower resolution. Motion compensated frames are produced also at the second lower resolution. The residual error frames are then combined with the motion compensated frames to produce video frames. Further, the video frames are up-scaled to the first resolution.

Abstract: The present invention provides a method of and system for determining whether a local area of a compressed video stream represented by a plurality of DCT encoded blocks subject to decoding and filtering/scaling is a stationary area or an interlaced moving area. Further, given such information, the invention relates to dynamically switching between frame- or field-based operations in a smart way, thus optimizing the output picture quality. Also, a DCT-domain-filtering scheme for field-based filtering/scaling of frame-DCT data is provided herein.

Abstract: A complexity scalable decoder system and method. The system comprises: a decoder having a plurality of functional blocks for decoding compressed video data, the decoder further includes a plurality of scalable functions for selectively reducing a complexity of at least one of the functional blocks; and a local resource controller for generating a scaling strategy for the decoder, wherein the scaling strategy is selected in response to a complexity requirement received from a system resource manager, and wherein the scaling strategy is selected from a plurality of predetermined scaling strategies available to the local resource controller. Each of the predetermined scaling strategies may be selected from a look-up table designed off-line.

Abstract: A system and method for filtering interlaced video in the DCT domain. The invention implements an even length symmetric filter necessary for filtering the bottom field of pixel data using the steps of: decomposing the even symmetric spatial filter design into two identical odd length symmetric filter designs have a one pixel phase difference therebetween; creating a discrete cosine transform (DCT) filter that corresponds to the odd length symmetric filter designs; filtering the field of interlaced video data in the DCT domain using DCT filter to create a set of filtered DCT data; converting the set of filtered DCT data into a set of spatial domain data; and filtering the spatial domain data with a [1,1] filter.

Abstract: The present invention is directed to MPEG decoding with embedded resizing that includes detecting and interpolating moving areas in interlaced video in order to eliminate irregularities in the output video. According to the present invention, the decoding includes down scaling a motion vector. Also, detecting a moving area in an interlaced video reference frame and modifying the reduced resolution motion vector. Further, retrieving pixel values from the interlaced video reference frame according to the modified motion vector.

Abstract: Data compressed according to a lossy DCT-based algorithm, such as the MPEG or MPEG2 algorithms, is decompressed according to a dynamically-selected set of DCT coefficients, with unused coefficients masked out. A macroblock of the data exhibiting little motion is decompressed with a small subset of DCT coefficients, while a macroblock exhibiting more motion is decompressed using a larger subset of DCT coefficients up the full set of DCT coefficients. Average computational complexity is thus kept low, enabling the use of inexpensive equipment, while degradation is minimized.

Abstract: A method and system of regulating the computation load of an MPEG decoder in a video processing system are provided. The video processing system processes the header information of a compressed video data stream including a plurality of macroblocks with a motion vector associated therewith. Then, the computation load of each functional block of the MPEG decoder is adjusted according to predetermined criteria; thus, substantial computational overhead is desirably avoided.

Abstract: The present invention can complement and benefit virtually any method utilizing motion compensation to decode an inputted digital video data stream by determining a likely local nature of reference frame data area in the video data stream and then applying proper interpolation to the reference frame data area according to the determined likely local nature of the reference frame data area. The present invention can also complement and benefit virtually any decoding system utilizing motion compensation to decode an inputted digital video data stream by providing a motion compensation predictor that is adapted to determine a likely local nature of a reference frame data area in the video data stream and then apply proper interpolation to the reference frame data area according to the determined likely local nature of the reference frame data area.

Abstract: Nowadays, programmable components (604), rather than dedicated single-function components can perform continuous media processing in consumer devices, like digital television sets (610), set-top boxes, PCs, or VCRs. The media processing algorithms that are written for those programmable components (604), must be designed to provide a plurality of output quality levels in exchange for required processing resources. Since resources are finite, the media processing algorithms must be controlled in their resource usage and the output quality level they provide. Users of consumer devices do not like to see major changes in the quality of, for example, a video they are watching. Therefore, typical algorithm characteristics like the functions an algorithm comprises, the resource usage per function and the quality level per function are used to provide smoother quality transitions.