Sync license-plate-recognition from metro-analytics-catalog

.gitattributes

@@ -33,3 +33,4 @@ saved_model/**/* filter=lfs diff=lfs merge=lfs -text
 *.zip filter=lfs diff=lfs merge=lfs -text
 *.zst filter=lfs diff=lfs merge=lfs -text
 *tfevents* filter=lfs diff=lfs merge=lfs -text
+expected_output_dlstreamer.gif filter=lfs diff=lfs merge=lfs -text

README.md

@@ -1,7 +1,5 @@
 # License Plate Recognition
 
-> **Validated with:** OpenVINO 2026.1.0, DLStreamer 2026.0, Python 3.11+
-
 | Property | Value |
 |---|---|
 | **Category** | Object Detection + Optical Character Recognition |
@@ -114,7 +112,7 @@ A buffer probe extracts the recognized text from the inference metadata
 attached to each frame.
 The input is `ParkingVideo.mp4`, the short parking-lot clip downloaded by
 `export_and_quantize.sh` into the current directory.
-The annotated stream is muxed into `output.mp4` with H.264 (OpenH264).
+The annotated stream is muxed into `output_dlstreamer.mp4` with H.264 (OpenH264).
 
 ```python
 import os
@@ -138,17 +136,17 @@ OCR_XML = (
     "ch_PP-OCRv4_rec_infer/ch_PP-OCRv4_rec_infer.xml"
 )
 INPUT_VIDEO = "ParkingVideo.mp4"
-DEVICE = "CPU"
-PREPROC = "pre-process-backend=opencv"
+DEVICE = "GPU"
 
 pipeline_str = (
-    f"filesrc location={INPUT_VIDEO} ! decodebin3 ! queue ! "
-    f"gvadetect model={DETECTOR_XML} device={DEVICE} {PREPROC} ! queue ! "
+    f"filesrc location={INPUT_VIDEO} ! decodebin3 ! "
+    f"videoconvert ! queue ! "
+    f"gvadetect model={DETECTOR_XML} device={DEVICE} ! queue ! "
     f"videoconvert ! "
-    f"gvaclassify model={OCR_XML} device={DEVICE} {PREPROC} ! queue ! "
+    f"gvaclassify model={OCR_XML} device={DEVICE} ! queue ! "
     f"gvawatermark ! videoconvert ! video/x-raw,format=I420 ! "
     f"openh264enc ! h264parse ! "
-    f"mp4mux ! filesink name=sink location=output.mp4"
+    f"mp4mux ! filesink name=sink location=output_dlstreamer.mp4"
 )
 
 pipeline = Gst.parse_launch(pipeline_str)
@@ -188,17 +186,16 @@ bus.timed_pop_filtered(
 pipeline.set_state(Gst.State.NULL)
 ```
 
-To run on integrated GPU, change `DEVICE = "CPU"` to `DEVICE = "GPU"` and
-switch `PREPROC` to `"pre-process-backend=vaapi-surface-sharing"` and add
-`vapostproc ! video/x-raw(memory:VASurface)` after `decodebin3`, matching the
-upstream sample.
+To run on CPU, change `DEVICE = "GPU"` to `DEVICE = "CPU"`.
+For NPU, change `DEVICE = "GPU"` to `DEVICE = "NPU"` and use
+`batch-size=1` and `nireq=4` for best utilization.
 
 ### Try It on a Sample Video
 
 `export_and_quantize.sh` already downloaded `ParkingVideo.mp4` into the
 current directory, so the sample is ready to run.
 Execute the DLStreamer sample above.
-The annotated video is saved to `output.mp4` with green bounding boxes drawn
+The annotated video is saved to `output_dlstreamer.mp4` with green bounding boxes drawn
 by `gvawatermark` around every detected plate.
 The buffer probe prints one line per detected plate per frame.
 
@@ -221,6 +218,10 @@ If you only need the structured output and not the annotated video, replace `fil
 > video is encoded correctly. The warning comes from the OpenH264 library's
 > internal logging and does not indicate a real error.
 
+#### Expected Output
+
+![DLStreamer expected output](expected_output_dlstreamer.gif)
+
 ---
 
 ## License