Explain how AV_XVMC_RENDER_MAGIC got its seemingly arbitrary value.

Originally committed as revision 17342 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/xvmc.h

@@ -30,8 +30,8 @@
 #define AV_XVMC_STATE_PREDICTION               2  /**  the surface is needed for prediction, the codec manipulates this */
 #define AV_XVMC_STATE_OSD_SOURCE               4  /**  this surface is needed for subpicture rendering */
 #endif
-#define AV_XVMC_RENDER_MAGIC          0x1DC711C0  /**< magic value to ensure that regular pixel routines haven't corrupted the struct */
-//                                 1337 IDCT MCo
+#define AV_XVMC_RENDER_MAGIC          0x1DC711C0  /**< magic value to ensure that regular pixel routines haven't corrupted the struct
+                                                       the number is 1337 speak for the letters IDCT MCo (motion compensation) */
 
 struct xvmc_pix_fmt {
 /** Set by calling application