Figure 1. Top Level Scaler Options
When the Video Processing Functionality is chosen to be Scaler Only, the following options are available:
- Enable Color Space Conversion
- When selected, the Scaler Only subcore supports run-time configurable color space conversion from RGB to YUV 4:4:4 and vice versa between the input and output video streams.
Note: The coefficients are fixed and not programmable.
- Color Space Support
- Select the color spaces for which support is desired. If YUV 4:2:2 is selected, basic horizontal chroma resampling is included. If YUV 4:2:0 is selected, basic vertical chroma resampling is also included. The combination of Enable Color Space Conversion and Color Space Support for RGB, YUV 4:4:4, YUV 4:2:2, YUV 4:2:0 basically turns the Scaler Only configuration into a scaler with any to any format conversion.
Figure 2. Scaler Tab
The parameters on the Scaler tab are as follows:
- Algorithm
- The Scaler comes in three different quality levels each at different levels of
resource usage.
- Bilinear
- Bilinear scaling uses bilinear interpolation to calculate pixels.
- Bicubic
- Bicubic scaling is a little bit more demanding compared to bilinear scaling, and produces smoother pictures with less artifacts.
- Polyphase
- The picture quality (and resource usage) of a polyphase scaler depends largely on the number of filter taps used and number of filter phases used.
- Polyphase Filter Control
- When polyphase filtering is selected, the horizontal and vertical taps and
phases are defined here.
- Horizontal Taps
- Select 6, 8, 10, or 12 horizontal filter taps.
- Vertical Taps
- Select 6, 8, 10, or 12 vertical filter taps.
- Horizontal Phases
- Only 64 phases is currently supported.
- Vertical Phases
- Only 64 phases is currently supported.