[M4IF Technotes] What is the type of dc_scaler for intraDC?

[조진현]

Hi!
In intraDC quantization, dc_scaler is derived to minimize the visibility of artifacts.
Using piecewise liniar function, dc_scaler has several break-point. (Qp:1~4,5~8,9~24,25~31)
In luminance case, dc_scaler type is integer in all Qp range. (Refer to attatched file.)
On the other hand, in chrominance case, dc_scaler has floating point number.(x.0 or x.5 in range Qp 5~24) 
If dc_scaler type is integer, under point will be truncated. In this case, Qp 5 and 6 has same value(9). 
other 7 and 8, 9 and 10,... are same! That is, more break-points are added to chrominance linear equation 
between Qp 5 and Qp 24!
because IntraDC value is commonly large number, this truncation error will become serious!
So, I think, dc_scaler type must be float-type. Do you agree?
Regards,
Jin.H Cho
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