Sync worker-safety-detection from metro-analytics-catalog

README.md

@@ -45,6 +45,10 @@ python3 -m venv .venv --system-site-packages
 source .venv/bin/activate
 ```
 
+> **Note:** The `--system-site-packages` flag is required so the virtual
+> environment can access the system-installed OpenVINO and DLStreamer Python
+> packages.
+
 ---
 
 ## Getting Started
@@ -110,7 +114,7 @@ pipeline_str = (
     f"filesrc location={INPUT_VIDEO} ! decodebin3 ! "
     f"gvadetect model={MODEL_XML} device=CPU threshold=0.4 ! queue ! "
     f"gvawatermark ! videoconvert ! video/x-raw,format=I420 ! "
-    f"x264enc ! h264parse ! "
+    f"openh264enc ! h264parse ! "
     f"mp4mux ! filesink name=sink location=output.mp4"
 )
 pipeline = Gst.parse_launch(pipeline_str)
@@ -155,6 +159,12 @@ Expected console output (representative):
 The annotated video is saved to `output.mp4` with bounding boxes drawn by
 `gvawatermark` around each detected `safety_helmet` and `safety_jacket`.
 
+> **Known warning:** The `openh264enc` element prints
+> `[OpenH264] this = 0x..., Error:CWelsH264SVCEncoder::EncodeFrame(), cmInitParaError.`
+> on the first frame. This is a benign initialization message — the output
+> video is encoded correctly. The warning comes from the OpenH264 library's
+> internal logging and does not indicate a real error.
+
 **Device targets:**
 
 - `device=CPU` -- default in the sample code.