Film grain parameters adaptation based on viewing environment
AssigneeDolby Laboratories Licensing Corporation
InventorsGuan-Ming SU, Harshad KADU, Peng YIN
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Abstract
Methods, systems, and bitstream syntax are described for metadata signaling and film-grain parameter adaptation based on a viewing environment which may differ from a reference environment. Example adaptation models are provided for viewing parameters that include: ambient room illumination, viewing distance, and pixels per inch in a target display. Example systems include a single reference viewing environment model and a multi-reference viewing environment model supporting adaptation of film-grain model parameters via adaptation functions or interpolation.
Claims15
A method to process film grain metadata, the method comprising:
- receiving an input video bitstream and associated input film grain information;
- parsing the input film grain information to generate input film grain parameters (301) for generating film noise for a target display;
- accessing measured viewing parameters (312) for the target display, wherein the viewing parameters comprise an ambient light value, a pixels per inch value, and a viewing distance value;
- accessing reference viewing parameters for a reference display;
- adjusting (315) one or more of the input film grain parameters based on the measured viewing parameters and the reference viewing parameters to generate adjusted film grain parameters, wherein the adjusting comprises:
- generating ratio values between corresponding parameters in the measured and reference viewing parameters;
- adjusting film grain size and/or strength proportionally to a ratio of measured ambient luminance over reference ambient luminance;
- adjusting film grain size and/or strength proportionally to a ratio of measured viewing distance over reference viewing distance;
- and
- adjusting film grain size and/or strength proportionally to a ratio of measured pixels per inch over a reference pixels per inch;
- generating output film noise based at least on the adjusted film grain parameters;
- decoding the input video bitstream to generate decoded video pictures;
- and
- blending (320) the output film noise with the decoded video pictures to generate output video pictures on the target display.
A method to process film grain metadata, the method comprising:
- receiving an input video bitstream and accessing two or more sets of associated input film grain information (321), each set corresponding to a distinct target viewing environment, and each set comprising film grain parameters for generating film noise for a target display;
- accessing measured viewing parameters (312) for the target display;
- based on the measured viewing parameters, selecting (325) from the two or more sets of input film grain information a selected set of input film grain information with parameters closest to the measured viewing parameters;
- parsing the selected set of input film grain information to generate output film grain parameters for generating film noise for the target display;
- generating output film noise based at least on the output film grain parameters;
- decoding the input video bitstream to generate decoded video pictures;
- and
- blending (320) the output film noise with the decoded video pictures to generate output video pictures on the target display.
A method to process film grain metadata, the method comprising:
- receiving an input video bitstream and accessing two or more sets of associated input film grain information (331), each set corresponding to a distinct target viewing environment, and each set comprising film grain parameters for generating film noise for a target display;
- accessing measured viewing parameters (312) for the target display;
- based on the measured viewing parameters, interpolating (325) parameters from the two or more sets of input film grain information to generate output film grain parameters;
- generating output film noise based at least on the output film grain parameters;
- decoding the input video bitstream to generate decoded video pictures;
- and
- blending (320) the output film noise with the decoded video pictures to generate output video pictures on the target display.
Dependencies are inferred from the claim text.