BoxDecode Decode Types

BoxDecodeType is now a typed API (simaai::neat::BoxDecodeType / neat.BoxDecodeType) and should always be set explicitly for decode stages.

The runtime contract below comes from internals/gst_plugins/genericboxdecode_v2/gstneatboxdecode.cpp (infer_num_classes, infer_yolo_decoupled_classes, infer_yolo_packed_classes, compute_required_output_size).

Core Tensor Contract Rules

• YOLO-family decode types (yolo, yolov5*, yolov7*, yolov8*, yolov9*, yolov10*):
  • Decoupled heads: class-head depths must be repeatable and > 4.
  • Packed heads: each head depth must satisfy depth = 3 * (num_classes + 5) and be consistent across heads.
• yolo26: decoupled grouped heads with 4-channel raw l/t/r/b bbox tensors and repeatable class-head depths > 4.
• detr: class channels are inferred from the maximum depth across heads, and must be > 4.
• Other non-YOLO decode types (effdet, rcnn-stage1, centernet): fallback class inference uses max depth and requires > 4.
• Segmentation decode tokens (*-seg) enable segmentation-like output sizing in v2 (adds mask payload per detection).

Type Mapping

API enum	Backend token	Expected contract
BoxDecodeType::Yolo	yolo	YOLO decoupled or packed depth contract
BoxDecodeType::YoloV5	yolov5	YOLO decoupled or packed depth contract
BoxDecodeType::YoloV5Seg	yolov5-seg	YOLO depth contract + segmentation path
BoxDecodeType::YoloV7	yolov7	YOLO decoupled or packed depth contract
BoxDecodeType::YoloV7Seg	yolov7-seg	YOLO depth contract + segmentation path
BoxDecodeType::YoloV8	yolov8	YOLO decoupled or packed depth contract
BoxDecodeType::YoloV8Seg	yolov8-seg	YOLO depth contract + segmentation path
BoxDecodeType::YoloV8Pose	yolov8-pose	YOLO decoupled or packed depth contract
BoxDecodeType::YoloV9	yolov9	YOLO decoupled or packed depth contract
BoxDecodeType::YoloV9Seg	yolov9-seg	YOLO depth contract + segmentation path
BoxDecodeType::YoloV10	yolov10	YOLO decoupled or packed depth contract
BoxDecodeType::YoloV10Seg	yolov10-seg	YOLO depth contract + segmentation path
BoxDecodeType::YoloV26	yolo26	YOLO26 grouped raw l/t/r/b bbox heads + class-score heads
BoxDecodeType::Detr	detr	num_classes = max(depth) (must be > 4)
BoxDecodeType::EffDet	effdet	fallback max-depth inference (> 4)
BoxDecodeType::RcnnStage1	rcnn-stage1	fallback max-depth inference (> 4)
BoxDecodeType::Centernet	centernet	fallback max-depth inference (> 4)

Fail-Fast Behavior

• stages::BoxDecodeOptions now requires explicit construction with a decode type.
• stages::BoxDecode(...) and nodes::SimaBoxDecode(...) fail fast on BoxDecodeType::Unspecified.

Examples

simaai::neat::stages::BoxDecodeOptions opt(simaai::neat::BoxDecodeType::YoloV8);
opt.detection_threshold = 0.25;
opt.nms_iou_threshold = 0.5;
opt.top_k = 100;

opt = neat.ModelOptions()
opt.decode_type = neat.BoxDecodeType.YoloV8