1 pass rate control does not meet target rate, when intra period is not a mutiple of gop size

[jbrdbg]

Example coding with intra period 64 ( 2 x gop size):

vvencapp --preset faster -i RaceHorses_416x240_30.yuv -s 416x240 -r 30 -o str.bin --passes 1 --bitrate 100000 --IntraPeriod 64

gives

vvenc [info]: Total Frames | Bitrate Y-PSNR U-PSNR V-PSNR YUV-PSNR vvenc [info]: 300 a 102.1336 28.3847 33.7837 34.7943 29.3737

Using intra period 60:

vvencapp --preset faster -i RaceHorses_416x240_30.yuv -s 416x240 -r 30 -o str.bin --passes 1 --bitrate 100000 --IntraPeriod 60

gives

vvenc [info]: Total Frames | Bitrate Y-PSNR U-PSNR V-PSNR YUV-PSNR vvenc [info]: 300 a 184.0688 30.3672 35.5637 36.5731 31.3322