Okay I run a single batch file that does everything in one click:
Code:
ffmpeg.exe -framerate 24 -i "E:\x265\Sequence\%%05d.png" -strict -1 -pix_fmt yuv420p10 -vf colormatrix=bt601:bt709 -f YUV4MPEGPIPE - | x265.exe --input-depth 10 --uhd-bd --preset slow --crf 18 --colorprim bt2020 --transfer smpte-st-2084 --colormatrix bt2020nc --master-display "G(8500,39850)B(6550,2300)R(35400,14600)WP(15635,16450)L(10000000,1)" --max-cll "0,0" --output "E:\x265\output.hevc" - --y4m
mp4box.exe -add E:\X265\output.hevc -new E:\X265\output.mp4
pause
Thanks sneaker_ger.
EDIT Important!
The "-vf colormatrix=bt601:bt709" should be changed to "-vf scale=out_color_matrix=bt709" because the colormatrix command is only 8bit and it dithers down to 8bit.
While the scale=out_color_matrix=bt709 command bypasses any conversion while retains correct chroma values between RGB to YUV conversion.