Fix alignment functionality on Pi 5

picamera2/picamera2.py

@@ -933,13 +933,13 @@ def score_format(desired, actual):
     @staticmethod
     def align_stream(stream_config: dict, optimal=True) -> None:
         if optimal:
-            # Adjust the image size so that all planes are a mutliple of 32 bytes wide.
+            # Adjust the image size so that all planes are a mutliple of 32/64 bytes wide.
             # This matches the hardware behaviour and means we can be more efficient.
-            align = 32
+            align = 32 if Picamera2.platform == Platform.Platform.VC4 else 64
             if stream_config["format"] in ("YUV420", "YVU420"):
-                align = 64  # because the UV planes will have half this alignment
-            elif stream_config["format"] in ("XBGR8888", "XRGB8888"):
-                align = 16  # 4 channels per pixel gives us an automatic extra factor of 2
+                align *= 2  # because the UV planes will have half this alignment
+            elif stream_config["format"] in ("XBGR8888", "XRGB8888", "RGB161616", "BGR161616"):
+                align //= 2  # we have an automatic extra factor of 2 here
         else:
             align = 2
         size = stream_config["size"]

tests/alignment.py

@@ -0,0 +1,42 @@
+#!/usr/bin/python3
+
+from picamera2 import Picamera2, Platform
+
+picam2 = Picamera2()
+
+
+def compute_expected_stride(width, format):
+    if format in ("BGR888", "RGB888"):
+        return width * 3
+    elif format in ("XBGR8888", "XRGB8888"):
+        return width * 4
+    elif format in ("YUV420", "YVU420"):
+        return width
+    elif format in ("RGB161616", "BGR161616"):
+        return width * 6
+
+
+def test_alignment(width, format):
+    config = picam2.create_preview_configuration({'size': (width, 480), 'format': format}, buffer_count=1)
+    picam2.align_configuration(config)
+    picam2.configure(config)
+    actual_stride = config['main']['stride']
+    actual_width = config['main']['size'][0]
+    expected_stride = compute_expected_stride(actual_width, format)
+    if actual_stride != expected_stride:
+        print("ERROR: stride", actual_stride, "!=", expected_stride, "for format", format)
+        return 1
+    return 0
+
+
+formats = ["RGB888", "XRGB8888", "YUV420"]
+if picam2.platform == Platform.PISP:
+    formats.append("RGB161616")
+
+failures = 0
+for format in formats:
+    for width in range(512, 1025, 2):
+        print(format)
+        failures += test_alignment(width, format)
+
+print("Failures:", failures)

tests/test_list.txt

@@ -45,6 +45,7 @@ examples/tuning_file.py
 examples/video_with_config.py
 examples/window_offset.py
 examples/zoom.py
+tests/alignment.py
 tests/app_dual.py
 tests/app_full_test.py
 tests/app_test.py