ID 683329
Date 7/08/2024
Public

## 25.3. Deinterlacer IP Functional Description

The IP offers bob, weave, or motion adaptive deinterleavers.
Figure 67. Bob DeinterlacingThe figure shows the bob deinterlacing where the IP drops or deinterlaces interlaced fields. The IP passes all progressive frames through.
Figure 68. Weave Interlacing

The figure shows the weave deinterlacing, where the IP drops or deinterlaces interlaced fields. The IP passes all progressive frames through. For incoming F1 and F0, the weave deinterlacer deinterlaces or drops the fields based on the nibble values. For more information on nibble, refer to the Intel FPGA Streaming Video Protocol Specification.

For motion adaptive deinterlacer, the IP calculates the motion coefficient for each pixel and calculates the output pixel depending on motion coefficient. If the motion calculated from the current and the previous pixels is higher than the stored motion value, the stored motion value is irrelevant. The IP uses the calculated motion in the blending algorithm, which then becomes the next stored motion value. However, if the computed motion value is lower than the stored motion value, the following actions occur:

• The IP determines the next stored motion value by calculating the sum of three-fourth of the computed motion and one-fourths of the previously stored motion.
• The blending algorithm uses the next stored motion value.

This computed motion means that the motion that the blending algorithm uses climbs up immediately, but takes a few frames to stabilize. The motion-adaptive algorithm fills in the rows that are missing in the current field by calculating a function of other pixels in the current field and the three preceding fields as in the following sequence:

1. The IP collects pixels from the current field and the three preceding it (the X denotes the location of the desired output pixel).
Figure 69. Pixel Collection for the Motion-Adaptive Algorithm

2. The IP assembels these pixels into two 3×3 groups of pixels.
Figure 70. Pixel Assembly for the Motion-Adaptive AlgorithmThe figure shows the minimum absolute difference of the two groups.
3. The IP normalizes the minimum absolute difference value into the same range as the input pixel data. The IP compares the motion value with a recorded motion value for the same location in the previous frame. If it is greater, the IP keeps the new value. If the new value is less than the stored value, the IP uses the motion value that is the mean of the two values. This action reduces unpleasant flickering artifacts.
4. The IP uses a weighted mean of the interpolation pixels to calculate the output pixel and the equivalent to the output pixel in the previous field with the following equation: