Adapting luma mapping with chroma scaling to 4:4:4 RGB image content
At least a method and an apparatus are presented for efficiently encoding or decoding video by adapting Luma mapping with Chroma scaling for 4:4:4 RGB content. For example, a format of an image data of a video to encode is determined to be RGB format; and responsively a RGB mapping is applied to at least one of the color components of the image data wherein a RGB mapping adjusts the dynamic range of a color component of an image data in RGB format. Then, the video is encoded based on the at least one RGB mapped color component.
1 . A method for video decoding, comprising:
determining that a format of an image data of a video to decode is RGB format with a 4:4:4 chroma sampling structure;
responsively applying an inverse in-loop RGB mapping to at least one of the color components of the image data, wherein an RGB mapping adjusts a dynamic range of a color component of the image data in RGB format, wherein the in-loop RGB mapping is a luma mapping configured to adjust the dynamic range of one or more of the R. G, or B color components of the image data in the RGB format with a 4:4:4 chroma sampling structure; and
decoding the video based on the at least one inverse RGB mapped color component.
2 . The method of claim 1 , further comprising:
determining that an in-loop adaptive color transform is applied to the image data of a video to decode in RGB format, the adaptive color transform resulting into differential color components; and
responsively applying an inverse in-loop chroma residual scaling to differential color components wherein a chroma residual scaling adjusts the dynamic range of a differential component of an image data and applying an inverse adaptive color transform to the image data.
3 . The method of claim 1 , wherein an inverse RGB mapping is applied to all of the color components of the image data.
4 . An apparatus for video decoding, comprising one or more processors, wherein the one or more processors are configured to:
determine that a format of an image data of a video to decode is RGB format with a 4:4:4 chroma sampling structure;
apply an inverse in-loop RGB mapping to at least one of the color components of the image data wherein an RGB mapping adjusts a dynamic range of a color component of the image data in RGB format, wherein the in-loop RGB mapping is a luma mapping configured to adjust the dynamic range of one or more of the R, G, or B color components of the image data in the RGB format with a 4:4:4 chroma sampling structure; and
decode the video based on the at least one inverse RGB mapped color component.
5 . The apparatus of claim 4 , wherein the one or more processors are further configured to:
determine that an in-loop adaptive color transform is applied to the image data of a video to decode in RGB format, the adaptive color transform resulting into differential color components; and
apply an inverse in-loop chroma residual scaling to differential color components wherein a chroma residual scaling adjusts the dynamic range of a differential component of an image data and applying an inverse adaptive color transform to the image data.
6 . The apparatus of claim 4 , wherein an inverse RGB mapping is applied to all of the color components of the image data.
7 . A method for video encoding, comprising:
determining that a format of an image data of a video to encode is RGB format with a 4:4:4 chroma sampling structure;
responsively applying an in-loop RGB mapping to at least one of the color components of the image data wherein an RGB mapping adjusts a dynamic range of a color component of the image data in RGB format, wherein the in-loop RGB mapping is a luma mapping configured to adjust the dynamic range of one or more of the R, G, or B color components of the image data in the RGB format with a 4:4:4 chroma sampling structure; and
encoding the video based on the at least one RGB mapped color component.
8 . The method of claim 7 , further comprising:
determining that an in-loop adaptive color transform is applied to the image data of a video to decode in RGB format, the adaptive color transform resulting into differential color components; and
responsively applying an inverse in-loop chroma residual scaling to differential color components wherein a chroma residual scaling adjusts the dynamic range of a differential component of an image data and applying an inverse adaptive color transform to the image data.
9 . The method of claim 7 , wherein an inverse RGB mapping is applied to all of the color components of the image data.
10 . An apparatus for video encoding, comprising one or more processors, wherein the one or more processors are configured to:
determine that a format of an image data of a video to encode is RGB format with a 4:4:4 chroma sampling structure;
responsively apply an in-loop RGB mapping to at least one of the color components of the image data wherein the in-loop RGB mapping adjusts a dynamic range of a color component of an image data in RGB format, wherein the in-loop RGB mapping is a luma mapping configured to adjust the dynamic range of the R. G. or B color components of the image data in the RGB format with a 4:4:4 chroma sampling structure; and
encode the video based on the at least one RGB mapped color component.
11 . The apparatus of claim 10 , wherein the one or more processors are further configured to:
determine that an in-loop adaptive color transform is applied to the image data of a video to decode in RGB format, the adaptive color transform resulting into differential color components; and
apply an inverse in-loop chroma residual scaling to differential color components wherein a chroma residual scaling adjusts the dynamic range of a differential component of an image data and applying an inverse adaptive color transform to the image data.
12 . The apparatus of claim 10 , wherein an inverse RGB mapping is applied to all of the color components of the image data.
13 . A non-transitory computer readable medium containing instructions for performing the method of claim 1 , when executed by one or more processors.
14 . A non-transitory computer readable medium containing instructions for performing the method of claim 7 , when executed by one or more processors.
15 . A non-transitory computer readable medium containing data content encoded thereupon by:
determining that a format of an image data of the data content to encode is RGB format with a 4:4:4 chroma sampling structure;
responsively applying an in-loop RGB mapping to at least one of the color components of the image data wherein the in-loop RGB mapping adjusts a dynamic range of a color component of an image data in RGB format, wherein the in-loop RGB mapping is a luma mapping configured to adjust the dynamic range of one or more of the R.G. or B color components of the image data in the RGB format with a 4:4:4 chroma sampling structure; and
encoding the data content based on the at least one RGB mapped color component.
16 . The non-transitory computer readable medium of claim 15 , wherein encoded data content further comprises at least one syntax data element specifying that the in-loop RGB mapping is enabled for all of the color components.
17 . The non-transitory computer readable medium of claim 15 , wherein encoded data content further comprises at least one syntax data element specifying that an in-loop adaptive color transform is applied to the image data in RGB format, the adaptive color transform resulting into differential color components.