# US 2013/0156334 A1 · Video Codecs With Integrated Gamut Management > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0156334 A1 - Document ID: US20130156334A1 - Status: Published application - Kind: A1 - Application number: 13/707,114 - Filed: 2012-12-06 - Published: 2013-06-20 - Earliest claimed: 2011-12-19 - Assignees: Dolby Laboratories Licensing Corporation - Inventors: Steve Margerm; Peter W. Longhurst; Robin Atkins; Anders Ballestad - Web page: https://patentgrep.com/patent/US20130156334A1 ## CPC - H04N 19/60: using transform coding - H04N 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635) - H04N 19/124: Quantisation - H04N 19/154: Measured or subjectively estimated visual quality after decoding, e.g. measurement of distortion (use of rate-distortion criteria H04N19/147) - H04N 19/182: the unit being a pixel - H04N 19/186: the unit being a colour or a chrominance component - H04N 19/44: Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder - H04N 19/51: Motion estimation or motion compensation - H04N 1/6058: {Reduction of colour to a range of reproducible colours, e.g. to ink- reproducible colour gamut} - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/48: using compressed domain processing techniques other than decoding, e.g. modification of transform coefficients, variable length coding [VLC] data or run-length data (motion estimation in a transform domain H04N19/547; processing of decoded motion vectors H04N19/513) - H04N 19/86: involving reduction of coding artifacts, e.g. of blockiness - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Image decoders encoders and transcoders incorporate gamut transformations. The gamut transformations alter tone, color or other characteristics of image data. The gamut transformations may comprise interpolation, extrapolation, direct mapping of pixel values and/or modification of an expansion function. Gamut transformations may be applied to generate image output (video or still) adapted for display on a target display. ## Claims ### Claim 1 An image decoder comprising: a motion compensation stage; a gamut transformation unit upstream from the motion compensation stage, the gamut transformation unit configured to modify pixel values in image data being decoded; and a frequency domain to spatial domain converter, wherein the gamut transformation unit is configured to modify pixel values in macroblocks outputted by the frequency domain to spatial domain converter. ### Claim 2 (depends on 1) An image decoder according to claim 1 wherein the frequency domain to spatial domain converter comprises an inverse DCT or an inverse DWT. ### Claim 3 (depends on 1) An image decoder according to claim 1 comprising an inverse quantization stage upstream from the frequency domain to spatial domain converter wherein the gamut transformation unit is connected to receive data output by the inverse quantization stage and is configured to control a gamut transformation based at least in part on values for DC frequency coefficients included in the data output by the inverse quantization stage. ### Claim 4 (depends on 1) An image decoder according to claim 1 comprising an inverse quantization stage and a frequency domain to spatial domain converter upstream from the motion compensation stage wherein the gamut transformation unit is connected to receive frequency domain data output by the inverse quantization stage and is configured to modify values in the frequency domain data output by the inverse quantization stage. ### Claim 5 (depends on 1) An image decoder according to claim 1 comprising first and second parallel decoding pipelines upstream from the motion compensation stage wherein the gamut transformation unit is configured to interpolate between or extrapolate from values in corresponding macroblocks respectively output by the first and second parallel decoding pipelines. ### Claim 6 (depends on 5) An image decoder according to claim 5 wherein the macroblocks are frequency-domain macroblocks. ### Claim 7 (depends on 5) An image decoder according to claim 5 wherein the macroblocks are spatial-domain macroblocks. ### Claim 8 (depends on 1) An image decoder according to claim 1 comprising first and second parallel decoding pipelines upstream from the motion compensation stage wherein the gamut transformation unit is configured to modify values in macroblocks in the second decoding pipeline. ### Claim 9 (depends on 8) An image decoder according to claim 8 wherein the second decoding pipeline is connected to decode a difference signal representing a difference between a first video signal processed by the first decoding pipeline and a second video signal and the image decoder comprises a combining stage configured to receive and combine the difference signal and the first video signal to yield the second video signal. ### Claim 10 A method for decoding images comprising: processing an encoded signal to yield macroblocks; processing the macroblocks for motion compensation to yield output image data; and, upstream from processing the macroblocks for motion compensation, modifying pixel values in the macroblocks, wherein processing the encoded signal comprises performing a frequency domain to spatial domain transformation, and wherein modifying the pixel values is performed in the spatial domain. ### Claim 11 (depends on 10) A method according to claim 10 wherein performing the frequency domain to spatial domain conversion comprises performing an inverse DCT or an inverse DWT. ### Claim 12 (depends on 10) A method according to claim 10 comprising performing an inverse quantization operation upstream from performing the frequency domain to spatial domain transformation wherein modifying the pixel values in the macroblocks is performed based at least in part on values for DC frequency coefficients included in the data yielded by the inverse quantization operation. ### Claim 13 (depends on 10) A method according to claim 10 comprising performing an inverse quantization operation and a frequency domain to spatial domain transformation upstream from the motion compensation wherein modifying pixel values in the macroblocks comprises modifying values in frequency domain macroblocks. ### Claim 14 (depends on 10) A method according to claim 10 comprising processing first and second data in parallel decoding pipelines upstream from processing the macroblocks for motion compensation wherein modifying pixel values in the macroblocks comprises interpolating between or extrapolating from values in corresponding macroblocks respectively output by the first and second parallel decoding pipelines. ### Claim 15 (depends on 14) A method according to claim 14 wherein the macroblocks are frequency-domain macroblocks. ### Claim 16 (depends on 14) A method according to claim 14 wherein the macroblocks are spatial-domain macroblocks. ### Claim 17 (depends on 10) A method according to claim 10 comprising processing first and second data in first and second parallel decoding pipelines upstream from the motion compensation stage wherein modifying pixel values in the macroblocks comprises modifying values in macroblocks in the second decoding pipeline. ### Claim 18 (depends on 17) A method according to claim 17 wherein the second decoding pipeline is connected to decode a difference signal representing a difference between a first video signal processed by the first decoding pipeline and a second video signal and the method comprises combining the difference signal and the first video signal to yield the second video signal.