FFmpeg never supported msmpeg4v1 encoding.

Originally committed as revision 24356 to svn://svn.ffmpeg.org/ffmpeg/trunk

doc/general.texi

@@ -432,7 +432,7 @@ following image formats are supported:
 @item MPEG-2 video           @tab  X  @tab  X
 @item MPEG-4 part 2          @tab  X  @tab  X
     @ libxvidcore can be used alternatively for encoding.
-@item MPEG-4 part 2 Microsoft variant version 1  @tab  X  @tab  X
+@item MPEG-4 part 2 Microsoft variant version 1  @tab     @tab  X
 @item MPEG-4 part 2 Microsoft variant version 2  @tab  X  @tab  X
 @item MPEG-4 part 2 Microsoft variant version 3  @tab  X  @tab  X
 @item Nintendo Gamecube THP video  @tab     @tab  X