Abstract: A method decodes a video encoded as a compressed bitstream including frames constructed as blocks. The bitstream is variable length decoded and inverse quantized to determine motion vectors and DCT coefficients of the blocks of the bitstream. The DCT coefficients are then inverse discrete cosine transformed. A low-resolution block is generated for each reconstructed block, and the reconstructed blocks are motion compensated with the low-resolution blocks to decode the video.

Abstract: A method describes activity in a video sequence. The method measures intensity, direction, spatial, and temporal attributes in the video sequence, and the measured attributes are combined in a digital descriptor of the activity of the video sequence.

Abstract: A system and method for temporally processing an input video including input frames. Each frame has an associated frame play time, and the input video has a total input video play time that is a sum of the input frame play times of all of the input frames. Each of the input frames is classified according to a content characteristic of each frames. An output frame play time is allocated to each of the input frames that is based on the classified content characteristic of each of the input frames to generate a plurality of output frames that form an output video.

Abstract: A method selects an optimal coding mode for each macroblock in a video. Each macroblock can be coded according a number of candidate coding modes. A difference between an input macroblock and a predicted macroblock is determined in a transform-domain. The difference is quantized to yield a quantized difference. An inverse quantization is performed on the quantized difference to yield a reconstructed difference. A rate required to code the quantized difference is determined. A distortion is determined according to the difference and the reconstructed difference. Then, a cost is determined for each candidate mode based on the rate and the distortion, and the candidate coding mode that yields a minimum cost is selected as the optimal coding mode for the macroblock.

Abstract: A method and system transcodes an input video based on a first transformation kernel to an output video based on a second transformation kernel. The first and second transformation kernels are different, and the transcoding is performed entirely in a transform-domain. Coefficients of a single transform kernel matrix are determined. Then, input coefficients of the input video are converted to output coefficients of the output video using only the single transform kernel matrix. The input video can be based on DCT coefficients, and the output video can be based on HT coefficients. Alternatively, the input video can be based on HT coefficients, and the output video can be based on DCT coefficients. In addition, the ouput video can have a reduced a spatial resolution from the input video.

Abstract: A method and system processes a compressed input video. The compressed input video is processed to produce an interlaced picture, and macroblock coding information of the input video. The interlaced picture has a first spatial resolution, and a top-field and a bottom-field. The top-field and the bottom-field of the interlaced picture are filtered adaptively according to the macroblock coding information to produce a progressive picture with a second spatial resolution less than the first spatial resolution.

Abstract: A method transcodes an input video to an output video, which can have a lower bit rate than the input video. Sets of rate values and corresponding sets of distortion values are determined for each components of the output video. There is one set of rate values and one corresponding set of distortion values for each component in the output video. The components include a requantization of the input video, inserted resynchronization markers, and inserted intra-blocks. Then, bits are allocated to each of the components in the output video according to the associated set of rate values and the associated corresponding set of distortion values.

Abstract: A model stored in a memory accessible by a video transcoder includes a first rate-distortion function modeling a requantization of an input video. A second-rate distortion function models a resynchronization marker insertion rate for the transcoded video, and a third rate-distortion function models an intra-block insertion rate for the transcoded video.

Abstract: A method codes an output bitstream of an input video so the decoded output bitstream has a constant perceived quality. A base layer bitstream having a constant bit-rate is generated from the input video, and an input enhancement layer bitstream is generated from a difference between the input video and the base layer bitstream. Rate and distortion characteristics are extracted from the base layer bitstream and the input enhancement layer bitstream, and an output enhancement layer bitstream having a variable bit-rate is generated from the input enhancement layer bitstream according to the rate and distortion characteristics. The base layer bitstream and the output enhancement layer bitstream, in combination, form an output bitstream having a variable bit-rate and a constant distortion.

Abstract: A method encodes an inter-frame of a compressed video, the inter-frame including multiple macroblocks in a predetermined order. Each macroblock has an associated motion vector. For each current macroblock in the predetermined order, a set of near macroblocks are identified. An index is assigned to each near macroblock. A difference between the motion vector of the current macroblock and the motion vector of each near macroblocks is determined. The indices of the near macroblocks are then sorted in order of the differences and appended to the inter-frame.

Abstract: A method conceals errors in an intra-fame of compressed video. The intra-frame is decoded to multiple macroblocks. Each macroblock including pixels arranged in a rectangular array. A lost macroblock is identified during the decoding. Pixels along an outer boundary of the lost macroblock are concealed from nearest candidate pixels along outer boundaries of macroblocks immediately adjacent to the lost macroblock. All other pixels in the lost macroblock are concealed from nearest candidate pixels selected from previously concealed pixels in the lost macroblock.

Abstract: A method classifies pixels in an image by first partitioning the image into blocks. A variance of an intensity is determined for each pixel, and for each block the pixel with the maximum variance is identified. Then, the blocks are classified into classes according to the maximum variance.

Abstract: A method filters pixels in an image, by first partitioning the image into blocks. Edge block are identified. A variance of an intensity for each pixel in each edge block is determined. Then, each pixel in each edge block is filtered with a filter that is dependant on the variance of the pixel.

Abstract: A method classifies pixels in an image. The image can be a decompressed image that was compressed using a block-based compression process. A filter is applied to each pixel in the image to determine a mean intensity value of the pixel. The mean is used to determine a mean-square intensity for each pixel, which in turn is used to determine a variance of the intensity for each pixel. The mean-square represents an average power of a DC component in the image, and the variance represents an average power of AC frequency components in the image. The pixels are then classified according to the variance as being either smooth, edge, or texture pixels. Blocks in the image can then be classified according to the classified pixels, and blocking artifacts and ringing artifacts in the blocks can then be filtered according to the block classification.

Abstract: A method analyzes a high-level syntax and structure of a continuous compressed video according to a plurality of states. First, a set of hidden Markov models for each of the states is trained with a training video segmented into known states. Then, a set of domain specific features are extracted from a fixed-length sliding window of the continuous compressed video, and a set of maximum likelihoods is determined for each set of domain specific features using the sets of trained hidden Markov models. Finally, dynamic programming is applied to each set of maximum likelihoods to determine a specific state for each fixed-length sliding window of frames of the compressed video.

Abstract: A digital video format converter and method therefor includes a first and second converter. The first converter receives a digital video signal and converts, in the frequency domain, inter-coded pictures in the digital video signal into intra-coded pictures. The first converter performs motion compensation in the frequency domain on the inter-coded pictures in the digital video signal to convert the inter-coded pictures into intra-coded pictures. The second converter down converts output of the first converter. Further signal processing then completes placing the digital video signal output by the second converter in a format acceptable to standard lower definition digital decoders.

Abstract: A method acquires compressed videos. Intra-, or inter-frames of each compressed video are acquired at a fixed sampling rate. Joint analysis is applied concurrently and in parallel to the compressed videos to determine a variable and non-uniform temporal sampling rate for each compressed video so that a combined distortion is minimized and a combined frame rate constraint is satisfied. Each compressed video is then sampled at the associated variable and non-uniform temporal sampling rate to produce output compressed videos having variable temporal resolutions.

Abstract: A method acquires a plurality of input videos. The frames of each input video are acquired at a fixed sampling rate. Joint analysis is applied concurrently and in parallel to the input videos to determine a variable and non-uniform temporal sampling rate for each input video so that a combined distortion is minimized and a combined frame rate constraint is satisfied. Each input video is then sampled at the associated variable and non-uniform temporal sampling rate to produce output videos having variable temporal resolutions.

Abstract: A method transmits a video over a network as a bit stream of packets. Real-time feedback information on conditions of the network is received while transmitting the packets. A probability of packet loss is based on the real-time feedback. Then, redundant packets are generated for selected packets of the bit stream if the probability of packet loss is greater than a predetermined threshold.

Abstract: A method encodes a video by first measuring a variance of pixel intensities in a current frame. A number of bits to encode the current frame is assigned according to rate and buffer fullness constraints. A multiplier value is determined directly as a function of only the variance and the number of bits assigned to the current frame. Motion vectors between a reference frame and the current frame are estimated, and a sum of absolute difference (SAD) is based on a motion compensated residual between the reference frame and the current frame. An encoding mode is determined for each macro block in the current frame based on the sum of absolute difference, the motion vectors and the multiplier value. Then, the motion compensated residual is encoded based on the encoding mode, multiplier value and the number of allocated bits.