Signaling for reference picture resampling

Abstract

Devices, systems and methods for digital video coding, which includes reference picture resampling, are described. An example method for video processing includes performing a conversion between a video comprising one or more video segments comprising one or more video units and a bitstream representation of the video, wherein the bitstream representation conforms to a format rule and comprises information related to an adaptive resolution conversion (ARC) process, wherein the format rule specifies the applicability of the ARC process to a video segment, wherein an indication that the one or more video units of the video segment are coded with different resolutions is included in the bitstream representation in a syntax structure that is different from a header syntax structure, a decoder parameter set, a video parameter set, a picture parameter set, a sequence parameter set, and an adaptation parameter set.

What is claimed is: 
     
         1 . A method of processing video data, comprising:
 determining, for a conversion between a visual media data of a video and a bitstream of the video, a first information related to a first coding mode for the visual media data;   performing the conversion at least based on the first coding mode;   wherein the first coding mode comprising deriving prediction samples based on one or more reference pictures which have one or more different resolutions from that of a current picture including the visual media data, and   the resolution of the current picture is indicated by the first information, wherein the first information indicates at least one of a width W of the current picture and a height H of the current picture, wherein the width W is an integer multiple of a first value, and the height H is an integer multiple of a second value.   
     
     
         2 . The method of  claim 1 , wherein the first information is included in the bitstream in a sequence parameter set (SPS). 
     
     
         3 . The method of  claim 1 , wherein the first information is included in the bitstream in a picture parameter set (PPS). 
     
     
         4 . The method of  claim 1 , wherein the width W is less than or equal to a maximum value TW_max and is greater than or equal to a minimum value TW_min, and the height H is less than or equal to a maximum value TH_max and is greater than or equal to a minimum value TH_min. 
     
     
         5 . The method of  claim 4 , wherein the maximum value TW_max and/or the maximum value TH_max are included in the bitstream. 
     
     
         6 . The method of  claim 1 , wherein the first value and the second value are respectively based on at least one predefined value. 
     
     
         7 . The method of  claim 6 , wherein the predefined value is a positive integer. 
     
     
         8 . The method of  claim 1 , wherein the conversion comprises encoding the visual media data into the bitstream. 
     
     
         9 . The method of  claim 1 , wherein the conversion comprises decoding the visual media data from the bitstream. 
     
     
         10 . An apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to:
 determine, for a conversion between a visual media data of a video and a bitstream of the video, a first information related to a first coding mode for the visual media data;   perform the conversion at least based on the first coding mode;   wherein the first coding mode comprising deriving prediction samples based on one or more reference pictures which have one or more different resolutions from that of a current picture including the visual media data, and   the resolution of the current picture is indicated by the first information, wherein the first information indicates at least one of a width W of the current picture and a height H of the current picture, wherein the width W is an integer multiple of a first value, and the height H is an integer multiple of a second value.   
     
     
         11 . The apparatus of  claim 10 , wherein the first information is included in the bitstream in a sequence parameter set (SPS). 
     
     
         12 . The apparatus of  claim 10 , wherein the first information is included in the bitstream in a picture parameter set (PPS). 
     
     
         13 . The apparatus of  claim 10 , wherein the width W is less than or equal to a maximum value TW_max and is greater than or equal to a minimum value TW_min, and the height H is less than or equal to a maximum value TH_max and is greater than or equal to a minimum value TH_min. 
     
     
         14 . The apparatus of  claim 13 , wherein the maximum value TW_max and/or the maximum value TH_max are included in the bitstream. 
     
     
         15 . The apparatus of  claim 10 , wherein the first value and the second value are respectively based on at least one predefined value. 
     
     
         16 . The method of  claim 15 , wherein the predefined value is a positive integer. 
     
     
         17 . A non-transitory computer-readable storage medium storing instructions that cause a processor to:
 determine, for a conversion between a visual media data of a video and a bitstream of the video, a first information related to a first coding mode for the visual media data;   perform the conversion at least based on the first coding mode;   wherein the first coding mode comprising deriving prediction samples based on one or more reference pictures which have one or more different resolutions from that of a current picture including the visual media data, and   the resolution of the current picture is indicated by the first information, wherein the first information indicates at least one of a width W of the current picture and a height H of the current picture, wherein the width W is an integer multiple of a first value, and the height H is an integer multiple of a second value.   
     
     
         18 . The non-transitory computer-readable storage medium of  claim 17 , wherein the first information is included in the bitstream in a sequence parameter set (SPS). 
     
     
         19 . The non-transitory computer-readable storage medium of  claim 17 , wherein the first information is included in the bitstream in a picture parameter set (PPS). 
     
     
         20 . A non-transitory computer-readable recording medium storing a bitstream which is generated by a method performed by a video processing apparatus, wherein the method comprises:
 determining a first information related to a first coding mode for a visual media data of a video;   generating the bitstream from the visual media data at least based on the first coding mode;   wherein the first coding mode comprising deriving prediction samples based on one or more reference pictures which have one or more different resolutions from that of a current picture including the visual media data, and   the resolution of the current picture is indicated by the first information, wherein the first information indicates at least one of a width W of the current picture and a height H of the current picture, wherein the width W is an integer multiple of a first value, and the height H is an integer multiple of a second value.