}
/**
+ * Calculate motion vector component that should be added for direct blocks.
+ */
+static int calc_add_mv(MpegEncContext *s, int dir, int component)
+{
+ int mv_pos = s->mb_x * 2 + s->mb_y * 2 * s->b8_stride;
+ int sum;
+
+ sum = (s->next_picture_ptr->motion_val[0][mv_pos][component] +
+ s->next_picture_ptr->motion_val[0][mv_pos + 1][component] +
+ s->next_picture_ptr->motion_val[0][mv_pos + s->b8_stride][component] +
+ s->next_picture_ptr->motion_val[0][mv_pos + s->b8_stride + 1][component]) >> 2;
+ return dir ? -(sum >> 1) : ((sum + 1) >> 1);
+}
+
+/**
* Predict motion vector for B-frame macroblock.
*/
static inline void rv34_pred_b_vector(int A[2], int B[2], int C[2],
mx += r->dmv[dir][0];
my += r->dmv[dir][1];
- //XXX add vector for bidirectionally predicted blocks
+
+ if(block_type == RV34_MB_B_DIRECT){
+ mx += calc_add_mv(s, dir, 0);
+ my += calc_add_mv(s, dir, 1);
+ }
for(j = 0; j < 2; j++){
for(i = 0; i < 2; i++){
cur_pic->motion_val[dir][mv_pos + i + j*s->b8_stride][0] = mx;