Generate HDL and HLS Code from an RGB to YUV Color Space Conversion Algorithm

R2026b

This example shows how to generate HDL and HLS code from a MATLAB^® function that converts pixel data from RGB color space to YUV color space using a matrix transformation.

RGB to YUV conversion is a fundamental operation in video processing pipelines. Display and camera systems capture images in RGB. However, video compression standards and broadcast systems operate on luminance (Y) and chrominance (U, V) components because human vision is more sensitive to brightness than color detail. Separating these components enables more efficient compression and bandwidth usage.

Examine the MATLAB Design and Test Bench

Set up the MATLAB function and test bench for this example. In the MATLAB Command Window, enter:

mlhdlc_demo_setup("mlhdlc_rgb2yuv");

This command opens a temporary working folder with the files required to run this example. The folder includes these files:

• MATLAB function

• Test bench

• <model>_runme.m script, which includes the commands to generate HDL code

• <model>_runme_hls.m script, which includes the commands to generate HLS code

The MATLAB function, mlhdlc_rgb2yuv, accepts pixel coordinates and individual R, G, and B color channel values as inputs. It applies a 3x3 matrix transformation with an offset vector to produce the Y, U, and V components. The function uses persistent registers to pipeline the computation, outputting one converted pixel per call along with delayed coordinate signals.

To view the function, enter:

open mlhdlc_rgb2yuv.m;

The test bench file, mlhdlc_rgb2yuv_tb, verifies the behavior of the MATLAB function. It reads an image, streams each pixel through the design with horizontal and vertical blanking intervals, and displays the original RGB image alongside the reconstructed YUV output. To view the test bench, enter:

open mlhdlc_rgb2yuv_tb

Simulate the Design

To check for run-time errors, simulate the design by running the test bench. In the MATLAB Command Window, enter:

mlhdlc_rgb2yuv_tb;

Generate HDL Code

The mlhdlc_rgb2yuv_runme script specifies the target files, enables the settings required for this example, and generates HDL code.

The script specifies the MATLAB function and test bench, then creates a fixed-point configuration object and an HDL configuration object by using the coder.config function. It associates the test bench with both configuration objects.

designName = "mlhdlc_rgb2yuv";
designTB = "mlhdlc_rgb2yuv_tb";
fixptCfg = coder.config("fixpt");
fixptCfg.TestBenchName = designTB;
cfg = coder.config("hdl");
cfg.TestBenchName = designTB;

The script then generates code:

codegen("-float2fixed", "fixptCfg", "-config", "cfg", designName, ...
"-launchreport");

Run the Script

First, modify the mlhdlc_rgb2yuv_runme script. The script disables synthesis by default. Set the value for the SynthesizeGeneratedCode property to true:

cfg.SynthesizeGeneratedCode = true;

Update the settings for your synthesis tool:

cfg.SynthesisTool = "Xilinx Vivado";
cfg.SynthesisToolChipFamily = "Artix7";
cfg.SynthesisToolDeviceName = "xa7a100t";
cfg.SynthesisToolPackageName = "csg324";
cfg.SynthesisToolSpeedValue = "-1I";

Then, generate code by running the script:

mlhdlc_rgb2yuv_runme

After code generation completes, the report opens. Examine the generated HDL code in the report.

Generate HLS Code

The mlhdlc_rgb2yuv_runme_hls script specifies the target files, enables the settings required for this example, and generates HLS code.

The script specifies the MATLAB function and test bench, then creates a fixed-point configuration object and an HLS configuration object by using the coder.config function. It associates the test bench with both configuration objects.

designName = "mlhdlc_rgb2yuv";
designTB = "mlhdlc_rgb2yuv_tb";
fixptCfg = coder.config("fixpt");
fixptCfg.TestBenchName = designTB;

The script creates an HLS configuration object by using the coder.config function, associates the test bench, and enables simulation.

cfg = coder.config("hls");
cfg.TestBenchName = designTB;
cfg.GenerateHLSTestBench = true;
cfg.SimulateGeneratedCode = true;

The script then generates code:

codegen("-float2fixed", "fixptCfg", "-config", "cfg", designName, ...
"-launchreport");

Run the Script

First, modify the mlhdlc_rgb2yuv_runme_hls script. The script disables synthesis by default. Set the value for the SynthesizeGeneratedCode property to true:

cfg.SynthesizeGeneratedCode = true;

Depending on your synthesis tool, set one of these flags to true:

isCodingForStratusHLS = false;
isCodingForVitisHLS = true;

Depending on your synthesis tool, update these synthesis tool settings:

if isCodingForStratusHLS
    cfg.SynthesisTool = "Cadence Stratus HLS";
elseif isCodingForVitisHLS
    cfg.SynthesisTool = "Xilinx Vitis HLS";
    cfg.SynthesisToolChipFamily = "Artix7";
    cfg.SynthesisToolDeviceName = "xa7a100t";
    cfg.SynthesisToolPackageName = "csg324";
    cfg.SynthesisToolSpeedValue = "-1I";
end

Then, generate code by running the script:

mlhdlc_rgb2yuv_runme_hls

After code generation completes, the report opens. Examine the generated HLS code in the report.