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Internal Modules
181
SPRUHI7A – December 2012 – Revised June 2016
Copyright © 2012–2016, Texas Instruments Incorporated
High-Definition Video Processing Subsystem (HDVPSS)
1.2.9.2.2 Modes of Interpolation
1.2.9.2.2.1 Interpolation Mode 0
In mode 0, the interpolated field is created by simple line averaging from the original YUV data. That is,
the interpolated line is created by averaging its top and bottom line. Setting of MDT mode has no effect on
output pictures.
1.2.9.2.2.2 Interpolation Mode 1
In mode 1, the interpolated field is created by averaging pixels from fields before and after the current
field. In other words, if the current field is a top field, the interpolated bottom field picture is created by
averaging pixels from bottom field pictures before and after the current field. MDT setting has no effect on
the result.
1.2.9.2.2.3 Interpolation Mode 2 (EDI)
Mode 2 is an edge assisted interlace mode with edges detected from the luma information of a 2 × 7 (H ×
W) frame window. It detects seven possible edges between 45 and 135 degrees. Edges with slopes
greater than 135 degrees are treated as 135 degree lines, and edges with slopes less than 45 degrees
are treated as 45 degree lines.
Luma for missing lines are interpolated using original luma along the detected edge.
Motion value (MV) from the MDT module is used to select coefficients from a look up table on how 2D
interpolation from the current field and 3D interpolation from two fields adjacent to the current fields are
blended. The way to perform blending for chroma is slightly different than for luma, because the MV is
based on luma and extra care needs to be taken when blending is applied to chroma.
At this mode, edge-directed interpolation is applied to luma only. Vertical interpolation is performed for
chroma data.
1.2.9.2.2.4 Interpolation Mode 3 (EDI)
The edge detection method used in this mode is similar to interpolation mode 2. The only difference is that
the edge-directed interpolation is performed on both Luma and Chroma. Chroma is interpolated similarly
according to the edge vectors obtained based on luma information. The reason chroma is interpolated
slightly different is because of the down-sampled chroma data.
1.2.9.2.3 Motion Detection (MDT)
Motion values from the MDT module are calculated only based on luma information. The motion value is
used to determine how 2D and 3D interpolated results should be blended. The motion value is also used
in the Film Mode Detection (FMD) module to determine field and frame differences between frames, which
are in turn used in film mode detection.
The motion detection module in DEI supports 4-field mode.
Motion value (MV) is first estimated from y_f0 and y_f2 (current and two field delayed Y). The max value
of MV and one field delayed data of MV, MV_f1, is used to create the overall MV per pixel. Since this
motion detection method utilizes three fields of luma data and one field delayed MV, it is called 4-field
mode as MVs come from four fields of luma data.
There is one field delay between the YUV inputs and the YUV outputs. The “current_field” that the
interpolator works on is the YUV_f1 data.
1.2.9.2.4 Data Buffer Management
VPDMA is used to transfer the data in and out of DEI as shown in the following figure.