Techniques for providing chroma format scalability in image processing applications

A coding method, comprising:

• coding a multi-color source image in a scalable coding representation comprising:
• a base layer image containing a coded representation of a first color component of the source image according to a monochrome coding algorithm,
• an enhancement layer image containing a coded representation of a different second color component of the source image,
• wherein the base layer image and the enhancement layer image, when decoded, provide recovered source image data in which the first and second color components have a common resolution.

A decoding method, comprising:

• responsive to a determination that a recovered image is to be obtained at a base level of resolution, decoding a base layer image to obtain the recovered image, the base layer image containing coded representations of each of a plurality of color components of a source image, at least a first color component having a reduced resolution as compared to a resolution of a second color component,
• responsive to a determination that the recovered image is to be obtained at an enhanced level of resolution:
• decoding the base layer image containing the coded representations of each of the plurality of color components of a source image,
• decoding an enhancement layer image containing a coded representation of the first color component at a resolution that is increased with respect to the reduced resolution of the first color component to obtain residuals of the first color component, and
• merging the decoded base layer image and enhancement layer images to obtain the recovered image.

A coder comprising:

• a base layer coder having inputs for color component data representing a source image,
• an enhancement layer coding system comprising:
• an upsampler having an input for data corresponding to a first color component at a resolution corresponding to the color component's base layer resolution and an output for upsampled first color component data, and
• a residual generator having a first input coupled to the upsampler output, a second input for first color component data from the source image, and an output for residual first color component data.