[hevc 10bit encode] stream got a lower quality when using low qp value.

[feiwan1]

Encode 2 streams by using qp as 10/16, then decode them into p010 and calculate psnr. While qp set as 16 have a better quality than qp set as 10.

encode cmd:
sample_encode h265 -i stockholm_1280x720_604_1280x720.P010 -o stockholm-1-1-0-10-1-main10.h265 -w 1280 -h 720 -n 150 -p010 -cqp -qpp 10 -g 30 -num_slice 1 -r 1 -u veryslow -CodecProfile 2 -msb10 -hw

[dmitryermilov]

@feiwan1 , please attach two encoded streams.