avcodec/mpeg4videodec: Use smallest max_depth in get_vlc2()

The longest code here is 12 bits long and can be read in two attempts.

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/mpeg4videodec.c

@@ -203,14 +203,14 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g
         int length;
         int x = 0, y = 0;
 
-        length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
+        length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 2);
         if (length > 0)
             x = get_xbits(gb, length);
 
         if (!(ctx->divx_version == 500 && ctx->divx_build == 413))
             check_marker(s->avctx, gb, "before sprite_trajectory");
 
-        length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 3);
+        length = get_vlc2(gb, sprite_trajectory.table, SPRITE_TRAJ_VLC_BITS, 2);
         if (length > 0)
             y = get_xbits(gb, length);