Internal Modules
64
SPRUHI7A – December 2012 – Revised June 2016
Copyright © 2012–2016, Texas Instruments Incorporated
High-Definition Video Processing Subsystem (HDVPSS)
Anchor pixels for the top field have been sited up by half a pel (x = -1/8). The new interpolated pixel is
sited 3 half pels (x=3/8) down. Samples from the top field are distinct from samples in the bottom field.
For the bottom field, anchor pixels are sited 3 half pels up (x = -3/8). The new interpolated pixel is sited 1
half pel down (x=1/8).
The chroma upsampling filter accepts different coefficients for the top field and the bottom field. In the
case of progressive input, the coefficients for the top field and bottom field must be the same.
It should be noted that a different implementation could have been chosen to use the same coefficients for
the top and bottom fields. Instead of pushing pixels from the top to bottom of a picture, it can be shown
that pushing the bottom field through the upsampling filter from the bottom to the top of the picture permits
using the same values for x as in the top field case.
1.2.1.2.2 Edge Effects
Several methods with increasing levels of difficulty resulting in increasing quality can be employed to deal
with chroma pixels near the edges. In this module, the edge pixels can be mathematically approximated
using the same filter as the rest of the picture. Edge pixels are duplicated going into the filter.
1.2.1.2.3 Modes of Operation (VPDMA)
In both primary (PRI) and auxiliary (AUX) paths, the mode in which the VPDMA needs to be operated
depends whether the chroma upsampler and de-interlacers are enabled or not.
shows the
modes of operation.
Table 1-12. VPDMA Modes of Operation
Input data is 4:2:0
Input data is 4:2:2
Mode A
Mode B
These modes need to be set in the following register bit-fields of particular instances being used:
CHR_US_reg0.cfg_mode
Line_mode bitfield in VPDMA registers of format RD_LB_CLIENT_CTL_STATUS need to configured as
follows:
Mode A corresponds to MMR value 0
Mode B corresponds to MMR value 1
The following are the VPDMA client related bit-fields that need to be configured:
VPDMA_pri_chroma_cstat.line_mode
VPDMA_aux_chroma_cstat.line_mode
VPDMA_sec0_chroma_cstat.line_mode
VPDMA_sec1_chroma_cstat.line_mode
VPDMA_pri_luma_cstat.line_mode
VPDMA_aux_luma_cstat.line_mode
VPDMA_sec0_luma_cstat.line_mode
VPDMA_sec1_luma_cstat.line_mode
Important Notes:
1. For VPDMA luma clients, Mode B should always be used.
2. For VPDMA chroma clients, Mode A is used for 420 data and Mode B is used for 422 data.