Quantized difference used for weighting parameters derivation in bilateral filters

1. A method for video bitstream processing, comprising:

determining, for a conversion between a video and a bitstream of the video, that a reconstructed representation of a current sample of video data is to be subject to a bilateral filter defined by one or more parameters based, at least in part, on at least one of i) weighted sums of sample intensity differences (WSS Diff values) between a first window covering the current sample and a second window covering neighboring samples and ii) sample intensity differences (S Diff values) between the current sample and one or more neighboring samples, wherein multiple WSS Diff within a range are assigned a same weight and multiple S Diff within a range are assigned a same weight;

applying the bilateral filter defined by the one or more parameters to the reconstructed representation of the current sample of the video data; and

performing the conversion based on the applying,

wherein quantized values are generated by quantizing the WSS Diff values or the S Diff values by using linear quantization, and the one or more parameters are determined using the quantized values, and

wherein the one or more parameters are further based on a ratio (WSS Diff offset)/stepSize or (S Diff +offset)/stepSize, wherein WSS Diff is a weighted sum of sample intensity differences, S Diff is a sample intensity difference, stepSize is an integer number and offset is a number equal to one-half of the stepSize.

2. The method of claim 1 , wherein the one or more neighboring samples are adjacent to the current sample.

3. The method of claim 1 , wherein the one or more neighboring samples are non-adjacent to the current sample.

4. The method of claim 1 , wherein the one or more parameters are further based on a ratio WSS Diff /stepSize or S Diff /stepSize, wherein WSS Diff is a weighted sum of sample intensity differences, S Diff is a sample intensity difference and stepSize is defined as an integer number.

5. The method of claim 4 , wherein stepSize is a predetermined value.

6. The method of claim 4 , wherein stepSize is based on one or more of: a quantization parameter (QP), a block size, a block shape, or a coding mode.

7. The method of claim 1 , wherein the same parameter is assigned based on WSS Diff or S Diff value being larger than N or smaller than −M, N and M being positive values.

8. The method of claim 1 , wherein the conversion includes encoding the video into the bitstream.

9. The method of claim 1 , wherein the conversion includes decoding the video from the bitstream.

10. The method of claim 1 , wherein the conversion includes generating the bitstream from the video; and the method further comprises:

storing the bitstream in a non-transitory computer-readable recording medium.

11. An apparatus in a video system 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 video and a bitstream of the video, that a reconstructed representation of a current sample of video data is to be subject to a bilateral filter defined by one or more parameters based, at least in part, on at least one of i) weighted sums of sample intensity differences (WSS Diff values) between a first window covering the current sample and a second window covering neighboring samples and ii) sample intensity differences (S Diff values) between the current sample and one or more neighboring samples, wherein multiple WSS Diff within a range are assigned a same weight and multiple S Diff within a range are assigned a same weight;

apply the bilateral filter defined by the one or more parameters to the reconstructed representation of the current sample of the video data; and

perform the conversion based on the applying,

wherein quantized values are generated by quantizing the WSS Diff values or the S Diff values by using linear quantization, and the one or more parameters are determined using the quantized values, and

wherein the one or more parameters are further based on a ratio (WSS Diff +offset)/stepSize or (S Diff +offset)/stepSize, wherein WSS Diff is a weighted sum of sample intensity differences, S Diff is a sample intensity difference, stepSize is integer number and offset is a number equal to one-half of the stepSize.

12. A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises:

determining, for a conversion between a video and a bitstream of the video, that a reconstructed representation of a current sample of video data is to be subject to a bilateral filter defined by one or more parameters based, at least in part, on at least one of i) weighted sums of sample intensity differences (WSS Diff values) between a first window covering the current sample and a second window covering neighboring samples and ii) sample intensity differences (S Diff values) between the current sample and one or more neighboring samples, wherein multiple WSS Diff within a range are assigned a same weight and multiple S Diff within a range are assigned a same weight;

applying the bilateral filter defined by the one or more parameters to the reconstructed representation of the current sample of the video data; and

generating the bitstream from the video based on the applying,

wherein quantized values are generated by quantizing the WSS Diff values or the S Diff values by using linear quantization, and the one or more parameters are determined using the quantized values, and

wherein the one or more parameters are further based on a ratio (WSS Diff +offset)/stepSize or (S Diff +offset)/stepSize, wherein WSS Diff is a weighted sum of sample intensity differences, S Diff is a sample intensity difference, stepSize is an integer number and offset is a number equal to one-half of the stepSize.