Method and device for reconstructing image data from decoded image data

A device for reconstructing image data representative of original image data from decoded image data and parameters obtained from a bitstream, the parameters having been processed from the original image data, wherein the decoded image data and the reconstructed image data have different dynamic ranges and wherein the device comprises:

• at least one processor;
• and
• at least one memory having stored instructions operative, when executed by the at least one processor, to cause the device to, in response to a determination that a graphic is to be overlaid on a decoded image:
• select a recovery mode according to an information data indicating how the parameters have been processed;
• recover the parameters by applying the selected recovery mode;
• and
• reconstruct image data based on the decoded image data and the recovered parameters, comprising at least inverse mapping of luminance of the decoded image data and chroma correcting of the decoded image data;
• wherein the decoded image data and the reconstructed image data have different dynamic ranges.

A non-transitory computer-readable storage medium having stored instructions that, when executed by a processor, cause the processor to reconstruct image data representative of original image data from decoded image data and parameters obtained from a bitstream, the parameters having been processed from the original image data, by:

• in response to a determination that a graphic is to be overlaid on a decoded image:
• selecting a recovery mode according to information data indicating how the parameters have been processed;
• recovering the parameters by applying the selected recovery mode;
• and
• reconstructing image data based on the decoded image data and the recovered parameters, comprising at least inverse mapping of luminance of the decoded image data and chroma correcting of the decoded image data;
• wherein the decoded image data and the reconstructed image data have different dynamic ranges.