utils: test_convert: Fix GStreamer pipeline colorimetry and byte ordering

Set explicit JPEG colorimetry (1:4:0:0) on input and output caps to
ensure the correct BT601 full-range matrix is used for YUV conversions,
matching the convert binary behaviour.

Use videoconvert to output BGR for RGB test cases, accounting for
pispconvert's R/B channel swap on RGB output.

Author: naushir

utils/test_convert.py

@@ -101,6 +101,8 @@ def run_gstreamer(self, input_file, output_file, input_format, output_format):
         # Convert to GStreamer format names
         gst_in_format = self._pisp_to_gst_format(in_fmt['format'])
         gst_out_format = self._pisp_to_gst_format(out_fmt['format'])
+        # pispconvert swaps R/B for RGB, use BGR file output to match convert reference
+        gst_file_format = 'BGR' if gst_out_format == 'RGB' else gst_out_format
 
         # Build GStreamer pipeline
         pipeline = [
@@ -111,8 +113,11 @@ def run_gstreamer(self, input_file, output_file, input_format, output_format):
             f'height={in_fmt["height"]}',
             f'format={gst_in_format.lower()}',
             'framerate=30/1', '!',
+            'video/x-raw,colorimetry=1:4:0:0', '!',
             'pispconvert', '!',
-            f'video/x-raw,format={gst_out_format},width={out_fmt["width"]},height={out_fmt["height"]}', '!',
+            f'video/x-raw,format={gst_out_format},width={out_fmt["width"]},height={out_fmt["height"]},colorimetry=1:4:0:0', '!',
+            'videoconvert', '!',
+            f'video/x-raw,format={gst_file_format},width={out_fmt["width"]},height={out_fmt["height"]}', '!',
             'filesink', f'location={output_file}'
         ]