Blind noise analysis for video compression

Abstract

Example embodiments of the present invention provide a method or device for coding source video. The method or device may provide for a segment of video frames from the source video, computing a noise map for the segment of the source video where the noise map is computed from differences among pixels selected from spatially-distributed sampling patterns in the segment, computing control parameter adjustments based on the noise map, and coding the selected segment of source video according to control parameters generated from a default coding policy and the control parameter adjustments, where the default coding policy includes default control parameters of the encoder.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Patent Application No. 61 / 163,684, filed Mar. 26, 2009, entitled “Blind Noise Analysis For Video Compression,” which is herein incorporated by reference in its entirety.FIELD OF THE INVENTION[0002]The present invention is generally directed to video coding techniques and devices. In particular, the present invention is directed to estimate control parameter adjustments to a video encoder (also called coder in this application) and video decoder based on an estimation of noise in source video.BACKGROUND INFORMATION[0003]Studio video content producers often pre-edit uncompressed video to fit different requirements for channel distribution and format conversion. Another important and common edit step may be the color and film matching (also called analog support), which may require the injection of random noise into video frames to match characteristics of an analog film. Further, when the...

AI Technical Summary

Problems solved by technology

Further, when the source video or film includes computer-generated graphics, a large amount of noise may be purposefully added in areas of uniform colors to create natural-looking effects.

The conversion from high to low precision quantization may produce artifacts and require dithering to create virtual intermediate levels of colors not available in the final color space or bit depth.

Video materials having pre-edited content (even if in a 10 or 8 bit, non-compressed format) may create challenges to a block-based video encoder, e.g., a H.264 type encoder.

A video encoder may cause compression artifacts of quantization and / or block artifacts.

When compression artifacts are present in a video region that includes additive noise, they may become even more evident and visually annoying to a viewer because the geometrically defined structures of the compression artifacts may present in a random isotropic region.

The persistent artifacts on a playback screen may create unnatural effects which may degrade the perceptual quality.

In low bit rate video encoding, the additive noise from film production may also make it more difficult to achieve high perceptual quality since high frequency noise may affect the quantization process and the rate distortion optimization (RDOPT).

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