Apply reformat shortcut to hardware frames too

av/video/reformatter.py

@@ -291,6 +291,19 @@ def _reformat(
             frame = frame_sw
             src_format = cython.cast(lib.AVPixelFormat, frame.ptr.format)
 
+            # Check for shortcut again, in case dst_format matches the downloaded frame's sw_format
+            if (
+                dst_format == src_format
+                and width == frame.ptr.width
+                and height == frame.ptr.height
+                and dst_colorspace == src_colorspace
+                and src_color_range == dst_color_range
+                and not set_dst_color_trc
+                and not set_dst_color_primaries
+            ):
+                frame._init_user_attributes()
+                return frame
+
         if self.ptr == cython.NULL:
             self.ptr = sws_alloc_context()
             if self.ptr == cython.NULL:

tests/test_decode.py

@@ -308,6 +308,48 @@ def test_hardware_decode_download_preserves_frame_props(is_hw_owned: bool) -> No
     assert_video_frame_color_props_match(hw_frame, cpu_frame)
 
 
+def test_hardware_frame_reformat_matches_downloaded_frame() -> None:
+    hwdevices_available = av.codec.hwaccel.hwdevices_available()
+    if "HWACCEL_DEVICE_TYPE" not in os.environ:
+        pytest.skip(
+            "Set the HWACCEL_DEVICE_TYPE to run this test. "
+            f"Options are {' '.join(hwdevices_available)}"
+        )
+
+    hwaccel_device_type = os.environ["HWACCEL_DEVICE_TYPE"]
+    assert hwaccel_device_type in hwdevices_available, (
+        f"{hwaccel_device_type} not available"
+    )
+
+    test_video_path = fate_suite("h264/interlaced_crop.mp4")
+    downloaded_frame = decode_first_video_frame(
+        test_video_path,
+        av.codec.hwaccel.HWAccel(
+            device_type=hwaccel_device_type,
+            is_hw_owned=False,
+            allow_software_fallback=False,
+        ),
+    )
+    hw_frame = decode_first_video_frame(
+        test_video_path,
+        av.codec.hwaccel.HWAccel(
+            device_type=hwaccel_device_type,
+            is_hw_owned=True,
+            allow_software_fallback=False,
+        ),
+    )
+    assert downloaded_frame.format.name != hw_frame.format.name  # E.g. cuda vs nv12
+
+    # Download hw_frame to CPU and ensure the contents match downloaded_frame
+    sw_format = downloaded_frame.format.name
+    reformatted_frame = hw_frame.reformat(format=sw_format)
+    assert reformatted_frame.format.name == downloaded_frame.format.name
+    assert np.array_equal(
+        reformatted_frame.to_ndarray(format=sw_format),
+        downloaded_frame.to_ndarray(format=sw_format),
+    )
+
+
 def decode_first_video_frame(
     path: str, hwaccel: av.codec.hwaccel.HWAccel | None = None
 ) -> av.VideoFrame: