A method for motion estimation for use in video coding. In a predetermined search region, three starting rows are chosen, wherein a given prediction point is on the middle row, the N-th row. The method includes the following steps. (a) All points of the (N-2)-th, N-th, and (N+2)-th rows are chosen as checking points. (b) Block match errors for the checking points are calculated and a checking point which corresponds to a minimum block match error is defined as a candidate checking point. (c) A determination is made whether the candidate checking point is on the N-th row; if so, the method proceeds to step (g); otherwise, it proceeds to step (d). (d) It is determined that whether the candidate checking point is on the (N+2)-th row; if so, the method proceeds to step (e); otherwise, it proceeds to step (f). (e) N is incremented by two, all points of the (N+2)-th row are chosen as checking points, and step (b) is repeated. (f) N is decremented by two, all points of the (N-2)-th row are chosen as checking points, and step (b) is repeated. (g) All points of the (N-1)-th and (N+1)-th rows are chosen as checking points, block match errors for the checking points are calculated, and a checking point corresponding to the minimum block match error is defined as the candidate checking point, wherein the candidate checking point is used for determining the motion vector for video coding.

An apparatus and method for improving picture quality of a digital television is disclosed in which a picture image motion adaptive interpolation process is used when an interlaced picture is converted to a progressive picture, thereby providing optimal picture quality.

A method is provided for transcoding between video signals in two standards, DV and MPEG-2, each standard including discrete cosine transform (DCT) compressed signals. The each of the signals have macroblocks containing a plurality of DCT blocks. The DCT blocks are quantized according to respective quantization methods defined by the standards. The coefficients in each block are zigzag scanned, run-length coded and variable-length coded. The process variable-length decodes the coefficients and translates the quantized coefficients in the DV standard into quantized coefficients in the MPEG standard without fully dequantizing at least some of the DV coefficients and without performing an inverse DCT operation on any of the DCT coefficients. DV blocks that are encoded in a 248 format are translated into an 88 format before they are converted to MPEG-2 blocks. A method for transcoding from MPEG-2 to DV is also described. The MPEG-2 signals are intra-frame encoded, have a 4:2:2 chrominance format and an 88 frame-encoded block format. According to this method, converted 88 DV blocks that represent significant intra-field motion are converted from the 88 format to a 248 format. The method also controls which overflow coefficients in the DV signal are transcoded into corresponding coefficients in the MPEG-2 signal to control the data rate of the MPEG-2 signal.

A new motion estimation system and process for video compression is presented. The approach is computationally less expensive than typical spatial domain block matching algorithms. The search for matching blocks is performed in the frequency domain making extensive use of data already computed by the video encoding process. Moreover, additional good block matches can be recognized with this approach. A multi-tiered approach may be employed to combine the frequency domain analysis with existing spatial domain techniques.

A simple and efficient scheme is used to predict the number of bits needed to block of discrete cosine transform (DCT) coefficients with variable length coding (VLC). The scheme defines an easily computable parameter that has a strong correlation with the number of bits needed to encode the DCT data. Then a second order polynomial is developed to approximate the correlation and is used to predict the number of VLC bits that will be produced if a corresponding quantization matrix is used. The approach can be used to streamline the encoding/transcoding process for DV, and the result on that is presented. A further feature is the ability to present multiple results for multiple quantization matrixes.