gmc bitstream decoding support (the real motion compensation isnt implemnted yet)

Originally committed as revision 318 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mpeg4data.h

@@ -93,3 +93,9 @@ static RLTable rl_intra = {
     intra_run,
     intra_level,
 };
+
+static const UINT16 sprite_trajectory_tab[15][2] = {
+ {0x00, 2}, {0x02, 3},  {0x03, 3},  {0x04, 3}, {0x05, 3}, {0x06, 3},
+ {0x0E, 4}, {0x1E, 5},  {0x3E, 6},  {0x7E, 7}, {0xFE, 8}, 
+ {0x1FE, 9},{0x3FE, 10},{0x7FE, 11},{0xFFE, 12},
+};

libavcodec/mpegvideo.h

@@ -164,7 +164,11 @@ typedef struct MpegEncContext {
     int sprite_left;
     int sprite_top;
     int sprite_brightness_change;
-    int no_sprite_wraping_points;
+    int num_sprite_warping_points;
+    int sprite_offset[2][2];
+    int sprite_delta[2][2][2];
+    int sprite_shift[2][2];
+    int mcsel;
     int quant_precision;
     int quarter_sample;
     int scalability;