feat: Add librknnrt.so automatic download using reference project approach

- Modify build script to automatically install SDK and download librknnrt.so after extraction
- Add fallback download in package script if librknnrt.so missing from SDK
- Update README to reflect automatic librknnrt.so download
- Comment librknnrt BitBake recipe as unused (manual approach preferred)
- Add librknnrt.so to essential files verification in package script

This implementation copies the proven approach from brightsign-npu-gaze-extension
which manually downloads the Rockchip runtime library rather than using BitBake.
The manual approach is simpler and more reliable for this binary-only library.

Fixes missing librknnrt.so that was causing OpenCV DNN import errors.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: scottrfrancis

.claude/settings.local.json

@@ -79,7 +79,10 @@
       "Bash(./run_yolox_test.sh:*)",
       "Bash(./brightsign-x86_64-cobra-toolchain-9.1.52.sh:*)",
       "Bash(nm:*)",
-      "Bash(git stash pop:*)"
+      "Bash(git stash pop:*)",
+      "Bash(gh release create:*)",
+      "Bash(gh auth:*)",
+      "Bash(git stash push:*)"
     ],
     "deny": []
   }

README.md

@@ -6,7 +6,7 @@ Python CV development extension for BrightSign digital signage players (embedded
 
 __Provides__: Python 3.8, OpenCV, PyTorch, ONNX, RKNN toolkit, scientific computing stack and an extensible Python development environment
 
-__Target__: Enterprise edge CV applications (audience analytics, interactive displays, retail analytics)  
+__Target__: Enterprise edge CV applications (audience analytics, interactive displays, retail analytics)
 
 __Key requirement__: x86_64 development host (Apple Silicon incompatible due to RKNN toolchain)
 
@@ -62,12 +62,20 @@ __Time__: 60-90 min | __Prerequisites__: Docker, git, x86_64 host, BrightSign pl
 # Build extension (30-60 min)
 git clone git@github.com:brightsign/python-cv-dev-extension.git
 cd python-cv-dev-extension
+
+```
+
+```bash
 ./setup && ./build --extract-sdk
 
 # Package (5 min)
 ./brightsign-x86_64-cobra-toolchain-*.sh -d ./sdk -y
 ./package
 
+```
+
+```bash
+
 # Deploy & validate
 # Transfer .zip via DWS, install via SSH, then:
 export PLAYER_IP=${PLAYER_IP:-192.168.1.100}  # Replace with your player IP
@@ -759,7 +767,7 @@ if [ ! -d "sdk/sysroots/aarch64-oe-linux/usr/lib/python3.8/site-packages/torch"
 fi
 ```
 
-**Note**: The Rockchip RKNN runtime library (`librknnrt.so`) and Python packages are automatically included through BitBake recipes - no manual patching required.
+**Note**: The Rockchip RKNN runtime library (`librknnrt.so`) is automatically downloaded during SDK installation. Python packages are included through BitBake recipes.
 
 ### Docker Image Management
 
@@ -832,7 +840,7 @@ python3 -c "import cv2, pandas, torch, numpy; print('Core packages working')"
 
 The extension provides packages through two mechanisms:
 
-**✅ SDK-Built Packages (Always Available)**
+__✅ SDK-Built Packages (Always Available)__
 These are built into the extension and available immediately after sourcing `setup_python_env`:
 
 ```python

bsoe-recipes/meta-bs/recipes-open/librknnrt/librknnrt_2.3.2.bb

@@ -1,3 +1,7 @@
+# NOTE: This recipe is currently unused as librknnrt.so is downloaded manually
+# during SDK installation (similar to the reference project approach).
+# The manual download approach is simpler and more reliable for this binary-only library.
+
 SUMMARY = "RKNN Runtime Library for Rockchip NPU"
 DESCRIPTION = "Runtime library for executing RKNN models on Rockchip NPU hardware"
 HOMEPAGE = "https://github.com/airockchip/rknn-toolkit2"

build

@@ -229,6 +229,28 @@ if [ $? -eq 0 ]; then
             echo "✅ SDK extracted to ${SCRIPT_DIR}/${SDK_BASENAME}"
             # Clean up the copy in srv
             rm -f "$SDK_FILE"
+            
+            # Also install and patch SDK if requested
+            echo "Installing SDK to ./sdk directory..."
+            if "${SCRIPT_DIR}/${SDK_BASENAME}" -d "${SCRIPT_DIR}/sdk" -y; then
+                echo "✅ SDK installed to ./sdk"
+                
+                # Patch SDK with Rockchip libraries (same as reference project)
+                echo "Adding librknnrt.so to SDK..."
+                cd "${SCRIPT_DIR}/sdk/sysroots/aarch64-oe-linux/usr/lib"
+                if [ ! -f "librknnrt.so" ]; then
+                    if wget -q https://github.com/airockchip/rknn-toolkit2/raw/v2.3.2/rknpu2/runtime/Linux/librknn_api/aarch64/librknnrt.so; then
+                        echo "✅ librknnrt.so downloaded to SDK"
+                    else
+                        echo "⚠️  Failed to download librknnrt.so - continuing anyway"
+                    fi
+                else
+                    echo "✅ librknnrt.so already present in SDK"
+                fi
+                cd "${SCRIPT_DIR}"
+            else
+                echo "⚠️  SDK installation failed - SDK installer is available for manual installation"
+            fi
         else
             echo "❌ SDK file not found in /srv directory"
             echo "    Expected: ${SCRIPT_DIR}/srv/brightsign-x86_64-*-toolchain-*.sh"

package

@@ -160,7 +160,20 @@ copy_sdk_components() {
         cd - > /dev/null
     fi
 
-    # Copy libraries
+    # Ensure librknnrt.so is present (fallback if not in SDK)
+    if [ ! -f "$sdk_sysroot/usr/lib/librknnrt.so" ]; then
+        warn "librknnrt.so not found in SDK, downloading..."
+        if wget -q -O "$sdk_sysroot/usr/lib/librknnrt.so" \
+            https://github.com/airockchip/rknn-toolkit2/raw/v2.3.2/rknpu2/runtime/Linux/librknn_api/aarch64/librknnrt.so; then
+            success "librknnrt.so downloaded successfully"
+        else
+            error "Failed to download librknnrt.so - NPU functionality may not work"
+        fi
+    else
+        log "librknnrt.so found in SDK"
+    fi
+
+    # Copy libraries (including librknnrt.so)
     log "Copying libraries (this may take a few minutes)..."
     cp -r "$sdk_sysroot/usr/lib" install/usr/
 
@@ -456,6 +469,7 @@ verify_structure() {
         "sh/cleanup-extension"
         "sh/setup_python_env"
         "usr/bin/python3"
+        "usr/lib/librknnrt.so"
     )
 
     for file in "${essential_files[@]}"; do