SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The initial value for the phase value for vertical resizing is set by the RZi_V_PHS_Y for Luma and RZi_V_PHS_C for Chroma. These values are in the U14Q8 fractional format (values in the range [0 – 63.996]). When YUV4:2:2 data are output, the phase value for Luma and Chroma must be aligned; that is, RZi_V_PHS_Y = RZi_V_PHS_C.
The following constraint equation applies: | RZi_V_PHS_Y –RZx_V_PHS_C | <= RZi_V_DIF. This constraint means that at most the distance between the initial phases for Luma and Chroma is not expected to exceed the distance between two Luma pixels. The absolute value is used; therefore, the initial Luma phase can be greater than the initial Chroma phase or vice versa. As a reminder, the distance between two output pixels for Luma is given by RZi_V_DIF.
The initial value for the phase value for horizontal resizing is set by the RZi_H_PHS register. The RZi_H_PHS_ADJ register enables adjusting the horizontal phase for the Luma component when averaging is enabled (the averager disrupts the relative sampling point between Luma and Chroma when YUV4:2:2 co-sited data is input). The relative phase between Luma and Chroma is different before and after the horizontal averager. The vertical phase is not affected by the averager. Figure 9-103 shows the effect of the averager on the phases. RZi_H_PHS_ADJ is expected to be equal to 0 if the averager is disabled.