Abstract: A multi-directional comb filtering in a digital video decoder is provided. Some embodiments of the present invention provide for a method of filtering, using a multi-directional comb filter, pixel data from a sequence of fields of pixel data, wherein the fields of pixel data comprise a previous field, a current field and a next field, and wherein each of said fields includes a previous line, a current line, a next line.

Abstract: A multi-directional comb filtering in a digital video decoder is provided.

Abstract: In one example, a digital video resampler and decoder is disclosed. An input buffer is coupled to a source of a video signal oversampled by at least two times. A horizontal synchronization detector is coupled to the input buffer, and detects horizontal synchronization boundaries. A counter is coupled to the horizontal synchronization detector to count a number of samples between horizontal synchronization boundaries. A comparator is coupled to the counter and compares the counted number of samples to a reference count. A sample corrector is coupled to the input buffer and modifies a block of samples based on a result from the comparator. An output buffer is coupled to the sample corrector to hold the modified block of samples. A comb filter is coupled to the output buffer, and generates first and second three-dimensional color values based on the modified block of samples.

Abstract: An adaptive gain and offset control for a digital video analog to digital converter is provided. A gain indicator and/or an offset indicator, which are used as inputs control signals to an analog-to-digital converter, are determined based on a detected maximum level and a detected blanking level from an input video signal. The gain and offset indicators may be determined independently from a minimum level of the video signal.

Abstract: A digital video decoder architecture is provided wherein chrominance values are determined first, then luminance values are determined, in part, based on the previously determined chrominance values. In this architecture, luminance separation occurs after and based on one or more chrominance values.

Abstract: An image enhancement unit and method for enhancing the image quality of a video stream is presented. The image enhancement unit combines a contour enhancement unit, a luminance contrast stretching unit, a color transient improvement unit, and a color saturation control unit to enhance both the luminance and chrominance values in the video stream. Specifically, the contour enhancement unit processes the luminance values to improve the contours of the images in the video steam. The luminance contrast stretching unit further improves the luminance by enhancing the contrast in the images. The color transient improvement unit processes the chrominance values to remove blurring around along the edges of color transitions and the color saturation control unit increases the color saturation to improve the appearance of the images.

Abstract: A method and system for adjusting selected colors of an image is presented. A chrominance adjustment system in accordance with one embodiment of the present invention, determines whether the color of the current pixel is near a selected color. When the color of the current pixel is near the selected color the chrominance adjustment system calculates a color specific chrominance adjustment factor based on the current color and the selected color and adjusts the color of the current pixel using the color specific chrominance adjustment factor.

Abstract: A method and system for scaling an original image into a scaled image is disclosed. Rather than using the corresponding position in the original image to generate the pixels values of a current pixel in the scaled image, image scalers in accordance with the present invention, calculate a high frequency adjusted position based on the high frequency components of pixels near the corresponding position. Pixel values based on the high frequency adjusted position provide better picture quality for the scaled image than pixel values based on the corresponding position. Furthermore, some embodiments of the present invention also use sharpness compensation to further improve the picture quality of the scaled image.

Abstract: A method and system for accumulating stillness characteristics is presented. The method and system generates field stillness characteristics for a current pixel of a current field. The field stillness characteristic is accumulated with an accumulated stillness characteristic that corresponds to a pixel location of the current pixel. The accumulated stillness characteristic includes stillness information regarding previous pixels of previous fields in the same pixel location as the current pixel.

Abstract: A method and system for accumulating stillness characteristics is presented. The method and system generates field stillness characteristics for a current pixel of a current field. The field stillness characteristic is accumulated with an accumulated stillness characteristic that corresponds to a pixel location of the current pixel. The accumulated stillness characteristic includes stillness information regarding previous pixels of previous fields in the same pixel location as the current pixel.

Abstract: A method and system for performing still pixel detection is presented. In accordance with the present invention, still pixel detection can use multiple thresholds and multiple windows of pixels. In a particular embodiment of the present invention, a still pixel detection test is performed using a first window. If the first window test determines the pixel is a still pixel then the pixel is classified as a still pixel. If the first window test determines the pixel is not a still pixel, a still pixel detection test is performed using a second window. If the second window test determines the pixel is a still pixel then the pixel is classified as a still pixel. Otherwise, the pixel is not classified as a still pixel. Some embodiment of the present invention the still pixel tests use multiple thresholds to determine if a pixel is a still pixel.

Abstract: A method and system for characterizing structures in an image are presented. The method and system generates a structure checksum value based on a plurality of pixels in the image. The structure checksum is used as an index of a look-up table containing structure characteristics corresponding to the structure checksum values.

Abstract: A system and system for performing adaptive recursive noise reduction with still pixel detection on a video stream is presented. After processing a field pixels that were modified are stored in the field so that processing of later fields uses the modified pixels. Furthermore, the system uses novel still pixel detection routines that include multiple thresholds and multiple windows of pixels so that noise reduction is only performed on still pixels.

Abstract: A method and system for suppressing color-crossing error in decoded video signals is presented. The color-crossing error suppression method and system uses a first suppression technique at a pixel location for a first subset of fields exhibiting color-crossing error at a pixel location then uses a second suppression technique at the pixel location for a second subset of fields exhibiting color-crossing error at the pixel location. The second subset of fields follows the first subset of fields in the video signals.

Abstract: An image enhancement unit and method for enhancing the image quality of a video stream is presented. The image enhancement unit combines a contour enhancement unit, a luminance contrast stretching unit, a color transient improvement unit, and a color saturation control unit to enhance both the luminance and chrominance values in the video stream. Specifically, the contour enhancement unit processes the luminance values to improve the contours of the images in the video steam. The luminance contrast stretching unit further improves the luminance by enhancing the contrast in the images. The color transient improvement unit processes the chrominance values to remove blurring around along the edges of color transitions and the color saturation control unit increases the color saturation to improve the appearance of the images.

Abstract: A color saturation control unit and method for increasing the color saturation of an image is presented. A scaled saturation enhancement factor calculation unit generates a scaled saturation enhancement factor using a base saturation enhancement factor. A multiplier generates a saturation enhanced U chrominance value and a saturation enhanced V chrominance for the current pixel by multiplying the scaled saturation enhancement factor multiplied with the current chrominance values. The ratio of the saturation enhanced chrominance values should be equal to the ratio of the current chrominance values. A lookup table contains tabled saturation enhancement factors that can be used as the scaled saturation enhancement factor when the base saturation enhancement factor would cause the saturation enhanced U chrominance value or the saturation enhanced V chrominance value to exceed a valid range of chrominance values.

Abstract: An adaptive gain and offset control for a digital video analog to digital converter is provided. A gain indicator and/or an offset indicator, which are used as inputs control signals to an analog-to-digital converter, are determined based on a detected maximum level and a detected blanking level from an input video signal. The gain and offset indicators may be determined independently from a minimum level of the video signal.

Abstract: An image enhancement unit and method for enhancing the image quality of a video stream is presented. The image enhancement unit combines a contour enhancement unit, a luminance contrast stretching unit, a color transient improvement unit, and a color saturation control unit to enhance both the luminance and chrominance values in the video stream. Specifically, the contour enhancement unit processes the luminance values to improve the contours of the images in the video steam. The luminance contrast stretching unit further improves the luminance by enhancing the contrast in the images. The color transient improvement unit processes the chrominance values to remove blurring around along the edges of color transitions and the color saturation control unit increases the color saturation to improve the appearance of the images.

Abstract: A method and system for detecting color-crossing error in decoded video signals is presented. The color-crossing error detection method and system detects a color-crossing pattern in a set of corresponding pixels that share a pixel location. Each pixel of the set of corresponding pixels comes from a different field of a set of fields, which includes a current field having a current pixel. The method and system determines that color-crossing error exists at the current pixel when the color-crossing pattern exists for a user configurable number of sequential fields of the same field type at the pixel location.

Abstract: A color transient improvement unit and method for improving color transients to remove blurring along the edges of color transitions is presented. A transient characterization unit calculates various transient characterization values for a color transient detection window surrounding a current pixel. A transient threshold unit analyzes the transient characterization values to determine whether the color transient detection window contains a color transition. If a color transition exists, a transient correction unit generates an improved U chrominance value and an improved V chrominance value for the current pixel.