Adaptive filter for video processing applications

Abstract

The invention provides methods and apparatus for filtering an input video frame sequence to be encoded. An odd-tap filter is used to generate a first interpolated pixel from a group of pixels in an even field of the video sequence. An even-tap filter is used to generate a second interpolated pixel from a group of pixels in an odd field of the video sequence. The use of the even-tap filter for the group of pixels in the odd field ensures that the interpolated pixels generated for both the odd and even fields are located at substantially the same vertical location. This significantly reduces an undesirable vertical signal component which would otherwise be generated when the first and second interpolated pixels are subtracted as part of a field comparison operation. The resulting improvement in field comparison accuracy provides advantages in a variety of video preprocessing applications such as deinterlacing, inverse telecine processing, adaptive field/frame filtering and PAL video framing.

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