diff --git a/dlls/windowscodecs/converter.c b/dlls/windowscodecs/converter.c
index 4720a360feb..b1ee044d718 100644
--- a/dlls/windowscodecs/converter.c
+++ b/dlls/windowscodecs/converter.c
@@ -1555,6 +1555,66 @@ static HRESULT copypixels_to_16bppBGRA5551(struct FormatConverter *This, const W
     }
 }
 
+static HRESULT copypixels_to_64bppRGBA(struct FormatConverter *This, const WICRect *prc,
+    UINT cbStride, UINT cbBufferSize, BYTE *pbBuffer, enum pixelformat source_format)
+{
+    HRESULT hr;
+
+    switch (source_format)
+    {
+    case format_64bppRGBA:
+        if (prc)
+            return IWICBitmapSource_CopyPixels(This->source, prc, cbStride, cbBufferSize, pbBuffer);
+        return S_OK;
+
+    case format_48bppRGB:
+    {
+        UINT srcstride, srcdatasize;
+        const USHORT *srcpixel;
+        const BYTE *srcrow;
+        USHORT *dstpixel;
+        BYTE *srcdata;
+        BYTE *dstrow;
+        INT x, y;
+
+        if (!prc)
+            return S_OK;
+
+        srcstride = 6 * prc->Width;
+        srcdatasize = srcstride * prc->Height;
+
+        srcdata = malloc(srcdatasize);
+        if (!srcdata) return E_OUTOFMEMORY;
+
+        hr = IWICBitmapSource_CopyPixels(This->source, prc, srcstride, srcdatasize, srcdata);
+        if (SUCCEEDED(hr))
+        {
+            srcrow = srcdata;
+            dstrow = pbBuffer;
+            for (y = 0; y < prc->Height; y++)
+            {
+                srcpixel = (USHORT *)srcrow;
+                dstpixel= (USHORT *)dstrow;
+                for (x = 0; x < prc->Width; x++)
+                {
+                    *dstpixel++ = *srcpixel++;
+                    *dstpixel++ = *srcpixel++;
+                    *dstpixel++ = *srcpixel++;
+                    *dstpixel++ = 65535;
+                }
+                srcrow += srcstride;
+                dstrow += cbStride;
+            }
+        }
+        free(srcdata);
+        return hr;
+    }
+    default:
+        FIXME("Unimplemented conversion path %d.\n", source_format);
+        return WINCODEC_ERR_UNSUPPORTEDOPERATION;
+    }
+}
+
 static const struct pixelformatinfo supported_formats[] = {
     {format_1bppIndexed, &GUID_WICPixelFormat1bppIndexed, NULL, TRUE},
     {format_2bppIndexed, &GUID_WICPixelFormat2bppIndexed, NULL, TRUE},
@@ -1578,7 +1638,7 @@ static const struct pixelformatinfo supported_formats[] = {
     {format_32bppPBGRA, &GUID_WICPixelFormat32bppPBGRA, copypixels_to_32bppPBGRA},
     {format_32bppPRGBA, &GUID_WICPixelFormat32bppPRGBA, copypixels_to_32bppPRGBA},
     {format_48bppRGB, &GUID_WICPixelFormat48bppRGB, NULL},
-    {format_64bppRGBA, &GUID_WICPixelFormat64bppRGBA, NULL},
+    {format_64bppRGBA, &GUID_WICPixelFormat64bppRGBA, copypixels_to_64bppRGBA},
     {format_32bppCMYK, &GUID_WICPixelFormat32bppCMYK, NULL},
     {0}
 };
diff --git a/dlls/windowscodecs/tests/converter.c b/dlls/windowscodecs/tests/converter.c
index ff2a1e0a067..fd617a1feb7 100644
--- a/dlls/windowscodecs/tests/converter.c
+++ b/dlls/windowscodecs/tests/converter.c
@@ -622,6 +622,20 @@ static const WORD bits_16bppBGRA5551[] = {
 static const struct bitmap_data testdata_16bppBGRA5551 = {
     &GUID_WICPixelFormat16bppBGRA5551, 16, (BYTE*)bits_16bppBGRA5551, 32, 2, 96.0, 96.0};
 
+static const WORD bits_48bppRGB[] = {
+    0,0,0, 0,65535,0, 32767,32768,32767,
+    65535,65535,65535, 10,10,10, 0,0,10};
+
+static const struct bitmap_data testdata_48bppRGB = {
+    &GUID_WICPixelFormat48bppRGB, 48, (BYTE*)bits_48bppRGB, 3, 2, 96.0, 96.0};
+
+static const WORD bits_64bppRGBA_2[] = {
+    0,0,0,65535, 0,65535,0,65535, 32767,32768,32767,65535,
+    65535,65535,65535,65535, 10,10,10,65535, 0,0,10,65535,};
+
+static const struct bitmap_data testdata_64bppRGBA_2 = {
+    &GUID_WICPixelFormat64bppRGBA, 64, (BYTE*)bits_64bppRGBA_2, 3, 2, 96.0, 96.0};
+
 static void test_conversion(const struct bitmap_data *src, const struct bitmap_data *dst, const char *name, BOOL todo)
 {
     BitmapTestSrc *src_obj;
@@ -2075,6 +2089,7 @@ START_TEST(converter)
     test_conversion(&testdata_32bppGrayFloat, &testdata_24bppBGR_gray, "32bppGrayFloat -> 24bppBGR gray", FALSE);
     test_conversion(&testdata_32bppGrayFloat, &testdata_8bppGray, "32bppGrayFloat -> 8bppGray", FALSE);
     test_conversion(&testdata_32bppBGRA, &testdata_16bppBGRA5551, "32bppBGRA -> 16bppBGRA5551", FALSE);
+    test_conversion(&testdata_48bppRGB, &testdata_64bppRGBA_2, "48bppRGB -> 64bppRGBA", FALSE);
 
     test_invalid_conversion();
     test_default_converter();