OrbbecSDK_v2

C++ Sample: 1.stream.decimation

Overview

This sample demonstrates how to configure hardware decimation on Orbbec devices. The user selects the origin resolution and decimation factors, and the SDK auto-selects format and FPS.

Knowledge

Some devices (e.g. Gemini 435Le, Gemini 305) support hardware decimation, which downsamples the original sensor resolution to a smaller output resolution. A PresetResolutionConfig defines the origin resolution and decimation factors for Depth and IR sensors.

Code Overview

Step 1: Select origin resolution

List unique origin resolutions deduplicated from all available preset configs.

std::vector<OBPresetResolutionConfig> matchedPresets;
OBPresetResolutionConfig originPreset = selectOriginResolution(device, matchedPresets);

Step 2: Select decimation factor

For the chosen resolution, show available decimation factors and let the user pick one. If only one option exists, it is auto-selected.

OBPresetResolutionConfig presetConfig = selectDecimation(matchedPresets);

Apply preset config

Apply the selected config to the device. Gemini 305 uses a different decimation mechanism, so this step is skipped for 305.

if(!ob_smpl::isGemini305Device(vid, pid)) {
    device->setStructuredData(OB_STRUCT_PRESET_RESOLUTION_CONFIG, (uint8_t *)&presetConfig, sizeof(presetConfig));
}

Enable streams

Format and FPS are auto-selected by the SDK (OB_FORMAT_ANY / OB_FPS_ANY).

• Gemini 305 uses the decimation-config-based API:

OBHardwareDecimationConfig decimationConfig{};
decimationConfig.originWidth  = originWidth;
decimationConfig.originHeight = originHeight;
decimationConfig.factor       = presetConfig.depthDecimationFactor;
config->enableVideoStream(OB_SENSOR_DEPTH, decimationConfig);
config->enableVideoStream(OB_SENSOR_IR_LEFT, decimationConfig);
config->enableVideoStream(OB_SENSOR_IR_RIGHT, decimationConfig);

• Other devices find the matching profile by resolution and enable it directly:

auto profile = findProfile(depthSensor, originWidth, originHeight, presetConfig.depthDecimationFactor);
config->enableStream(profile);

The findProfile function handles two cases:

• Profiles with decimation (factor > 0): match by decimationConfig.originWidth/originHeight
• Profiles without decimation (factor == 0): match by output resolution originWidth / decimationFactor

Run Sample

Follow the console prompts to complete the 2-step selection:

1. Select an origin resolution
2. Select decimation factors for Depth and IR

Press the Esc key in the window to exit the program.

Result

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