/*
  * H.26L/H.264/AVC/JVT/14496-10/... motion vector predicion
  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**

  * @file

  * H.264 / AVC / MPEG4 part10 motion vector predicion.
  * @author Michael Niedermayer <michaelni@gmx.at>
  */
 

 #ifndef AVCODEC_H264_MVPRED_H
 #define AVCODEC_H264_MVPRED_H
 

 #include "internal.h"
 #include "avcodec.h"
 #include "h264.h"
 
 //#undef NDEBUG
 #include <assert.h>
 
 static inline int fetch_diagonal_mv(H264Context *h, const int16_t **C, int i, int list, int part_width){
     const int topright_ref= h->ref_cache[list][ i - 8 + part_width ];
     MpegEncContext *s = &h->s;
 
     /* there is no consistent mapping of mvs to neighboring locations that will
      * make mbaff happy, so we can't move all this logic to fill_caches */
     if(FRAME_MBAFF){
 

 #define SET_DIAG_MV(MV_OP, REF_OP, XY, Y4)\
                 const int xy = XY, y4 = Y4;\
                 const int mb_type = mb_types[xy+(y4>>2)*s->mb_stride];\

                 if(!USES_LIST(mb_type,list))\
                     return LIST_NOT_USED;\

                 mv = s->current_picture_ptr->motion_val[list][h->mb2b_xy[xy]+3 + y4*h->b_stride];\

                 h->mv_cache[list][scan8[0]-2][0] = mv[0];\
                 h->mv_cache[list][scan8[0]-2][1] = mv[1] MV_OP;\

                 return s->current_picture_ptr->ref_index[list][4*xy+1 + (y4&~1)] REF_OP;

 
         if(topright_ref == PART_NOT_AVAILABLE

            && i >= scan8[0]+8 && (i&7)==4

            && h->ref_cache[list][scan8[0]-1] != PART_NOT_AVAILABLE){

             const uint32_t *mb_types = s->current_picture_ptr->mb_type;
             const int16_t *mv;

             AV_ZERO32(h->mv_cache[list][scan8[0]-2]);

             *C = h->mv_cache[list][scan8[0]-2];
 

             if(!MB_FIELD

                && IS_INTERLACED(h->left_type[0])){
                 SET_DIAG_MV(*2, >>1, h->left_mb_xy[0]+s->mb_stride, (s->mb_y&1)*2+(i>>5));

                 assert(h->left_mb_xy[0] == h->left_mb_xy[1]);

             }
             if(MB_FIELD

                && !IS_INTERLACED(h->left_type[0])){

                 // left shift will turn LIST_NOT_USED into PART_NOT_AVAILABLE, but that's OK.

                 SET_DIAG_MV(/2, <<1, h->left_mb_xy[i>=36], ((i>>2))&3);

             }
         }
 #undef SET_DIAG_MV
     }
 
     if(topright_ref != PART_NOT_AVAILABLE){
         *C= h->mv_cache[list][ i - 8 + part_width ];
         return topright_ref;
     }else{
         tprintf(s->avctx, "topright MV not available\n");
 
         *C= h->mv_cache[list][ i - 8 - 1 ];
         return h->ref_cache[list][ i - 8 - 1 ];
     }
 }
 
 /**
  * gets the predicted MV.
  * @param n the block index
  * @param part_width the width of the partition (4, 8,16) -> (1, 2, 4)
  * @param mx the x component of the predicted motion vector
  * @param my the y component of the predicted motion vector
  */
 static inline void pred_motion(H264Context * const h, int n, int part_width, int list, int ref, int * const mx, int * const my){
     const int index8= scan8[n];
     const int top_ref=      h->ref_cache[list][ index8 - 8 ];
     const int left_ref=     h->ref_cache[list][ index8 - 1 ];
     const int16_t * const A= h->mv_cache[list][ index8 - 1 ];
     const int16_t * const B= h->mv_cache[list][ index8 - 8 ];
     const int16_t * C;
     int diagonal_ref, match_count;
 
     assert(part_width==1 || part_width==2 || part_width==4);
 
 /* mv_cache
   B . . A T T T T
   U . . L . . , .
   U . . L . . . .
   U . . L . . , .
   . . . L . . . .
 */
 
     diagonal_ref= fetch_diagonal_mv(h, &C, index8, list, part_width);
     match_count= (diagonal_ref==ref) + (top_ref==ref) + (left_ref==ref);
     tprintf(h->s.avctx, "pred_motion match_count=%d\n", match_count);
     if(match_count > 1){ //most common
         *mx= mid_pred(A[0], B[0], C[0]);
         *my= mid_pred(A[1], B[1], C[1]);
     }else if(match_count==1){
         if(left_ref==ref){
             *mx= A[0];
             *my= A[1];
         }else if(top_ref==ref){
             *mx= B[0];
             *my= B[1];
         }else{
             *mx= C[0];
             *my= C[1];
         }
     }else{
         if(top_ref == PART_NOT_AVAILABLE && diagonal_ref == PART_NOT_AVAILABLE && left_ref != PART_NOT_AVAILABLE){
             *mx= A[0];
             *my= A[1];
         }else{
             *mx= mid_pred(A[0], B[0], C[0]);
             *my= mid_pred(A[1], B[1], C[1]);
         }
     }
 
     tprintf(h->s.avctx, "pred_motion (%2d %2d %2d) (%2d %2d %2d) (%2d %2d %2d) -> (%2d %2d %2d) at %2d %2d %d list %d\n", top_ref, B[0], B[1],                    diagonal_ref, C[0], C[1], left_ref, A[0], A[1], ref, *mx, *my, h->s.mb_x, h->s.mb_y, n, list);
 }
 
 /**
  * gets the directionally predicted 16x8 MV.
  * @param n the block index
  * @param mx the x component of the predicted motion vector
  * @param my the y component of the predicted motion vector
  */
 static inline void pred_16x8_motion(H264Context * const h, int n, int list, int ref, int * const mx, int * const my){
     if(n==0){
         const int top_ref=      h->ref_cache[list][ scan8[0] - 8 ];
         const int16_t * const B= h->mv_cache[list][ scan8[0] - 8 ];
 
         tprintf(h->s.avctx, "pred_16x8: (%2d %2d %2d) at %2d %2d %d list %d\n", top_ref, B[0], B[1], h->s.mb_x, h->s.mb_y, n, list);
 
         if(top_ref == ref){
             *mx= B[0];
             *my= B[1];
             return;
         }
     }else{
         const int left_ref=     h->ref_cache[list][ scan8[8] - 1 ];
         const int16_t * const A= h->mv_cache[list][ scan8[8] - 1 ];
 
         tprintf(h->s.avctx, "pred_16x8: (%2d %2d %2d) at %2d %2d %d list %d\n", left_ref, A[0], A[1], h->s.mb_x, h->s.mb_y, n, list);
 
         if(left_ref == ref){
             *mx= A[0];
             *my= A[1];
             return;
         }
     }
 
     //RARE
     pred_motion(h, n, 4, list, ref, mx, my);
 }
 
 /**
  * gets the directionally predicted 8x16 MV.
  * @param n the block index
  * @param mx the x component of the predicted motion vector
  * @param my the y component of the predicted motion vector
  */
 static inline void pred_8x16_motion(H264Context * const h, int n, int list, int ref, int * const mx, int * const my){
     if(n==0){
         const int left_ref=      h->ref_cache[list][ scan8[0] - 1 ];
         const int16_t * const A=  h->mv_cache[list][ scan8[0] - 1 ];
 
         tprintf(h->s.avctx, "pred_8x16: (%2d %2d %2d) at %2d %2d %d list %d\n", left_ref, A[0], A[1], h->s.mb_x, h->s.mb_y, n, list);
 
         if(left_ref == ref){
             *mx= A[0];
             *my= A[1];
             return;
         }
     }else{
         const int16_t * C;
         int diagonal_ref;
 
         diagonal_ref= fetch_diagonal_mv(h, &C, scan8[4], list, 2);
 
         tprintf(h->s.avctx, "pred_8x16: (%2d %2d %2d) at %2d %2d %d list %d\n", diagonal_ref, C[0], C[1], h->s.mb_x, h->s.mb_y, n, list);
 
         if(diagonal_ref == ref){
             *mx= C[0];
             *my= C[1];
             return;
         }
     }
 
     //RARE
     pred_motion(h, n, 2, list, ref, mx, my);
 }
 
 static inline void pred_pskip_motion(H264Context * const h, int * const mx, int * const my){
     const int top_ref = h->ref_cache[0][ scan8[0] - 8 ];
     const int left_ref= h->ref_cache[0][ scan8[0] - 1 ];
 
     tprintf(h->s.avctx, "pred_pskip: (%d) (%d) at %2d %2d\n", top_ref, left_ref, h->s.mb_x, h->s.mb_y);
 
     if(top_ref == PART_NOT_AVAILABLE || left_ref == PART_NOT_AVAILABLE

        || !( top_ref | AV_RN32A(h->mv_cache[0][ scan8[0] - 8 ]))
        || !(left_ref | AV_RN32A(h->mv_cache[0][ scan8[0] - 1 ]))){

 
         *mx = *my = 0;
         return;
     }
 
     pred_motion(h, 0, 4, 0, 0, mx, my);
 
     return;
 }

 
 #endif /* AVCODEC_H264_MVPRED_H */