coreml: move prediction onto background thread

plugins/coreml/package.json

@@ -41,5 +41,5 @@
    "devDependencies": {
       "@scrypted/sdk": "file:../../sdk"
    },
-   "version": "0.0.26"
+   "version": "0.0.27"
 }

plugins/coreml/src/coreml/__init__.py

@@ -6,6 +6,10 @@
 import coremltools as ct
 import os
 from PIL import Image
+import asyncio
+import concurrent.futures
+
+predictExecutor = concurrent.futures.ThreadPoolExecutor(2, "CoreML-Predict")
 
 def parse_label_contents(contents: str):
     lines = contents.splitlines()
@@ -36,6 +40,7 @@ def __init__(self, nativeId: str | None = None):
         labels_contents = scrypted_sdk.zip.open(
             'fs/coco_labels.txt').read().decode('utf8')
         self.labels = parse_label_contents(labels_contents)
+        self.loop = asyncio.get_event_loop()
 
     # width, height, channels
     def get_input_details(self) -> Tuple[int, int, int]:
@@ -44,8 +49,12 @@ def get_input_details(self) -> Tuple[int, int, int]:
     def get_input_size(self) -> Tuple[float, float]:
         return (self.inputwidth, self.inputheight)
 
-    def detect_once(self, input: Image.Image, settings: Any, src_size, cvss):
-        out_dict = self.model.predict({'image': input, 'confidenceThreshold': .2 })
+    async def detect_once(self, input: Image.Image, settings: Any, src_size, cvss):
+        # run in executor if this is the plugin loop
+        if asyncio.get_event_loop() is self.loop:
+            out_dict = await asyncio.get_event_loop().run_in_executor(predictExecutor, lambda: self.model.predict({'image': input, 'confidenceThreshold': .2 }))
+        else:
+            out_dict = self.model.predict({'image': input, 'confidenceThreshold': .2 })
 
         coordinatesList = out_dict['coordinates']