One of the conditions to derive allowBtSplit in 6.4.1 is: – Otherwise if all of the following conditions are true, allowBtSplit is set equal to FALSE – btSplit is equal to SPLIT_BT_VER – x0 + cbWidth is greater than pic_width_in_luma_samples – y0 + cbHeight is greater than pic_width_in_luma_samples

In the last comparison, y0 + cbHeight is compared to pic_width_in_luma_samples instead of pic_height_in_luma_samples. Is that a typo?

Here is a list of some more typos and small issues that I found:

In section 8.2.4.2.1, when generating the reference samples p, there is a typo in step 1 "the reference samples refUnfilt[ x ][ y ] with x = −1, y = −1 refH − 1 and x = 0..refW − 1, y = −1 as output" where the ".." are missing for y=-1..refH-1.

In section 8.2.4.2.2 "The refW + refH − 1 neighbouring samples refUnfilt[ x ][ y ] that are constructed samples prior to the in-loop filter process, with x = −1, y = −1..refH − 1 and x = 0..refW − 1, y = −1": there are refW + refH + 1 samples.

In section 8.2.4.2.3, the outputs are currently listed as one of the inputs. They should be listed separately.

In section 8.2.4.2.3 step 3 "the value of refUnfilt[ x ][ y ] is set equal to p the value of refUnfilt[ x − 1 ][ y ]", the "p" before the "the value of" should be removed.

In section 8.2.4.2.4 at the end when p[x][y] is derived, equation (8-23) sets pF[x][-1] instead of p[x][-1].

In section 8.2.2, cbWidth and cbHeight should be added as inputs to the process.

General question about the order in which inputs to a process are listed (it may not be important): In some processes, an array is needed as input together with its size, as for example in process 8.2.4.2.3: " Inputs to this process are: – reference samples refUnfilt[ x ][ y ] with x = −1, y = −1..refH − 1 and x = 0..refW − 1, y = −1 for intra sample prediction, – a variable refW specifying the reference samples width, – a variable refH specifying the reference samples height, " Would it make more sense to list the size of the array BEFORE listing the array? Otherwise the first input contains two variables (in the example above refH and refW) that are defined afterwards.

Problem: For bottom boundary ( y0 + cbHeight > pic_height_in_luma_samples, x0 + cbWidth <= pic_width_in_luma_samples) and cbSize is smaller then MinQTSizeY case:

allowSplitBtHor and allowSplitBtVer are both true, because of the the condition below in 6.4.1 is false: -perpCbPos + perpCbSize is greater than perpMaxPicSize and cbSize is greater than MinQtSizeY

if both of allowSplitBtHor and allowSplitBtVer are true. mtt_split_cu_vertical_flag is present, which should not be present in this case. The same problem will happen in right boundary and cbSize is smaller then MinQTSizeY case.

Fix: Reform the allowBtSplit conditions in 6.4.1 as follow to fix the problem and that make sure corner case is correct.

The variable allowBtSplit is derived as follows: –If one or more of the following conditions are true, allowBtSplit is set equal to FALSE:

–cbSize is less than or equal to MinBtSizeY –cbWidth is greater than MaxBtSizeY –cbHeight is greater than MaxBtSizeY –mttDepth is greater than or equal to MaxMttDepth + depthOffset –perpCbPos + perpCbSize is greater than perpMaxPicSize and cbSize is greater than MinQtSizeY

–Otherwise if all of the following conditions are true, allowBtSplit is set equal to FALSE

–btSplit is equal to SPLIT_BT_VER –x0 + cbWidth is greater than pic_width_in_luma_samples –y0 + cbHeight is greater than pic_width_in_luma_samples

–Otherwise if all of the following conditions are true, allowBtSplit is set equal to FALSE:

–btSplit is equal to SPLIT_BT_VER –y0 + cbHeight is greater than pic_height_in_luma_samples

–Otherwise if all of the following conditions are true, allowBtSplit is set equal to FALSE:

–btSplit is equal to SPLIT_BT_HOR –x0 + cbWidth is greater than pic_width_in_luma_samples –y0 + cbHeight is smaller than or equal to pic_height_in_luma_samples

–Otherwise if all of the following conditions are true, allowBtSplit is set equal to FALSE:

–mttDepth is greater than 0 –partIdx is equal to 1 –MttSplitMode[ x0 ][ y0 ][ mttDepth − 1 ] is equal to parallelTtSplit

–Otherwise, allowBtSplit is set equal to TRUE.