+/** @param rgb RGB data; packed RGB 16:16:16, 48bpp, 16R, 16G, 16B,
+ * with the 2-byte value for each R/G/B component stored as
+ * little-endian; i.e. AV_PIX_FMT_RGB48LE.
+ * @param dst Buffer to fill with packed 16-bit XYZ data, i.e. first
+ * 16-bit word is X, second is Y etc.
+ * @param size size of RGB image in pixels.
+ * @param size stride of RGB data in pixels.
+ */
+extern void rgb_to_xyz (
+ uint8_t const * rgb,
+ uint16_t* dst,
+ dcp::Size size,
+ int stride,
+ ColourConversion const & conversion,
+ boost::optional<NoteHandler> note = boost::optional<NoteHandler>()
+ );