Abstract: A system and method for detecting and reducing mosquito noise are disclosed. Areas within a frame with mosquito noise are detected by calculating the variance of the luminance blocks in a macroblock, determining the minimum variance of the macroblock luminance blocks, and comparing the minimum variance to a mosquito noise threshold. If the minimum variance is greater than the mosquito noise threshold, then the macroblock is considered a high activity macroblock and the corresponding macroblock bit in the frame bitmap is set. If the minimum variance is less than or equal to the mosquito noise threshold, then the macroblock is considered a low activity macroblock, and the corresponding macroblock bit in the frame bit map is cleared. If the current macroblock bit is set in the corresponding frame bitmap or if at least one of its adjacent eight macroblock bits is set in the corresponding frame bitmap, then the current macroblock requires mosquito noise reduction.

Abstract: A digital video signal encoder and method for detecting and encoding noise is disclosed. In a frame in a video signal, the variance of at least four macroblock luminance blocks is calculated. The Log2 of the minimum of these variances is determined. A running sum of the Log2 calculations is calculated and compared to a noise threshold to determine whether or not the frame contains noise. In one embodiment, a frame is determined to contain noise if the running sum is greater than a noise threshold and encodes the remaining portion of the frame as noise. In another embodiment, a current frame is determined to contain noise and is encoded as noise if the previous frame contained noise. The present invention may encode noise by overriding the original bit rate quantiser scale and/or removing at least one high frequency from a noise block using a DCT filter.

Abstract: A method for controlling a video stream bit rate while encoding a macroblock of a video stream having pictures comprising the step of using a quantiser_scale_code of the general form: quantiser—scale—code=ROUND(A+B(D+logC(MIN{VAR[luma—0], . . . ,VAR[luma—n]}))) with A being an adjustable gear shift parameter; and B being an adjustable gas pedal parameter; and [luma_n] being a nth luminance block of said macroblock; and D being a constant parameter depending on the encoded picture type.

Abstract: A system and method for detecting and reducing mosquito noise are disclosed. Areas within a frame with mosquito noise are detected by calculating the variance of the luminance blocks in a macroblock, determining the minimum variance of the macroblock luminance blocks, and comparing the minimum variance to a mosquito noise threshold. If the minimum variance is greater than the mosquito noise threshold, then the macroblock is considered a high activity macroblock and the corresponding macroblock bit in the frame bitmap is set. If the minimum variance is less than or equal to the mosquito noise threshold, then the macroblock is considered a low activity macroblock, and the corresponding macroblock bit in the frame bit map is cleared. If the current macroblock bit is set in the corresponding frame bitmap or if at least one of its adjacent eight macroblock bits is set in the corresponding frame bitmap, then the current macroblock requires mosquito noise reduction.

Abstract: A digital video signal encoder and method for detecting and encoding noise is disclosed. In a frame in a video signal, the variance of at least four macroblock luminance blocks is calculated. The Log2 of the minimum of these variances is determined. A running sum of the Log2 calculations is calculated and compared to a noise threshold to determine whether or not the frame contains noise. In one embodiment, a frame is determined to contain noise if the running sum is greater than a noise threshold and encodes the remaining portion of the frame as noise. In another embodiment, a current frame is determined to contain noise and is encoded as noise if the previous frame contained noise. The present invention may encode noise by overriding the original bit rate quantiser scale and/or removing at least one high frequency from a noise block using a DCT filter.