Dolby Laboratories Licensing Corporation

Christopher J Vogt

Walter Christian Gish

David Ruhoff

Zhen Li

Jon S McElvain

Hyung-Suk Kim

Donald Pian

Kimball Darr Thurston, Iii

Jon Scott Mcelvain

The quantization parameter QP is well-known in digital video compression as an indication of picture quality. Digital symbols representing a moving image are quantized with a quantizing step that is a function QSN of the quantization parameter QP, which function QSN has been normalized to the most significant bit of the bit depth of the digital symbols. As a result, the effect of a given QP is essentially independent of bit depth a particular QP value has a standard effect on image quality, regardless of bit depth. The invention is useful, for example, in encoding and decoding at different bit depths, to generate compatible, bitstreams having different bit depths, and to allow different bit depths for different components of a video signal by compressing each with the same fidelity (i.e., the same QP).

Quantization control for variable bit depth

Enhancing image dynamic range is described. An input video signal that is represented in a first color space with a first color gamut, which is related to a first dynamic range, is converted to a video signal that is represented in a second color space with a second color gamut. The second color space is associated with a second dynamic range. At least two (e.g., three) color-related components of the converted video signal are mapped over the second dynamic range.

Extending image dynamic range

A substantially rectangular spectral representation is synthesized, which is adapted to produce image capture device sensor outputs if applied to an image capture device. The synthesized substantially rectangular spectral representation can be utilized in generating output color values of an output color space from image capture device sensor outputs, where the image capture device sensor outputs correspond to an image captured by an image capture device. The generated output color values correspond to colors perceived by the human visual system for the same image as that captured by the image capture device. Image capture device gamut is also determined.

Spectral synthesis for image capture device processing

A first image stream has a first dynamic range and a first color space. First and the second image streams are received in a layered codec. The second image stream has a second dynamic range, which is higher than the first dynamic range. The first image stream is in the codec's base layer; the second image stream is in its enhancement layer. The first image stream is encoded to obtain an encoded image stream, which is decoded to obtain a decoded image stream. The decoded image stream is converted from the first non-linear or linear color space to a second, different color space to obtain a color converted image stream. A higher dynamic range image representation of the color converted image stream is generated to obtain a transformed image stream. Inverse tone mapping parameters are generated based on the transformed image stream and the second image stream.

Compatible compression of high dynamic range, visual dynamic range, and wide color gamut video

A substantially rectangular spectral representation is synthesized, which is adapted to produce either (a) image capture device sensor outputs if applied to an image capture device or (b) color values if applied to corresponding analysis functions. Spectral expansion, which can be used in various image processing methods, is achieved with the synthesized spectral representation.

Spectral image processing

A digital cinema signal is encoded to produce a resulting coded digital cinema bitstream. Decoding the resulting coded digital cinema bitstream allows backwards-compatible delivery of digital cinema content. A digital image or video signal is preprocessed to produce two normalized digital image or video signals of differing quality levels and forward and inverse mapping parameters, which relate the normalized digital image or video signals. The preprocessing can be used prior to the encoding of a digital cinema signal to enable backwards-compatible delivery of digital cinema content.

Growing community of inventors

Laguna Niguel, CA, United States of America

Christopher J Vogt