1/*
2 * H.26L/H.264/AVC/JVT/14496-10/... motion vector predicion
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * H.264 / AVC / MPEG4 part10 motion vector predicion.
25 * @author Michael Niedermayer <michaelni@gmx.at>
26 */
27
28#ifndef AVCODEC_H264_MVPRED_H
29#define AVCODEC_H264_MVPRED_H
30
31#include "internal.h"
32#include "avcodec.h"
33#include "h264.h"
34
35//#undef NDEBUG
36#include <assert.h>
37
38static inline int fetch_diagonal_mv(H264Context *h, const int16_t **C, int i, int list, int part_width){
39    const int topright_ref= h->ref_cache[list][ i - 8 + part_width ];
40    MpegEncContext *s = &h->s;
41
42    /* there is no consistent mapping of mvs to neighboring locations that will
43     * make mbaff happy, so we can't move all this logic to fill_caches */
44    if(FRAME_MBAFF){
45
46#define SET_DIAG_MV(MV_OP, REF_OP, XY, Y4)\
47                const int xy = XY, y4 = Y4;\
48                const int mb_type = mb_types[xy+(y4>>2)*s->mb_stride];\
49                if(!USES_LIST(mb_type,list))\
50                    return LIST_NOT_USED;\
51                mv = s->current_picture_ptr->motion_val[list][h->mb2b_xy[xy]+3 + y4*h->b_stride];\
52                h->mv_cache[list][scan8[0]-2][0] = mv[0];\
53                h->mv_cache[list][scan8[0]-2][1] = mv[1] MV_OP;\
54                return s->current_picture_ptr->ref_index[list][4*xy+1 + (y4&~1)] REF_OP;
55
56        if(topright_ref == PART_NOT_AVAILABLE
57           && i >= scan8[0]+8 && (i&7)==4
58           && h->ref_cache[list][scan8[0]-1] != PART_NOT_AVAILABLE){
59            const uint32_t *mb_types = s->current_picture_ptr->mb_type;
60            const int16_t *mv;
61            AV_ZERO32(h->mv_cache[list][scan8[0]-2]);
62            *C = h->mv_cache[list][scan8[0]-2];
63
64            if(!MB_FIELD
65               && IS_INTERLACED(h->left_type[0])){
66                SET_DIAG_MV(*2, >>1, h->left_mb_xy[0]+s->mb_stride, (s->mb_y&1)*2+(i>>5));
67                assert(h->left_mb_xy[0] == h->left_mb_xy[1]);
68            }
69            if(MB_FIELD
70               && !IS_INTERLACED(h->left_type[0])){
71                // left shift will turn LIST_NOT_USED into PART_NOT_AVAILABLE, but that's OK.
72                SET_DIAG_MV(/2, <<1, h->left_mb_xy[i>=36], ((i>>2))&3);
73            }
74        }
75#undef SET_DIAG_MV
76    }
77
78    if(topright_ref != PART_NOT_AVAILABLE){
79        *C= h->mv_cache[list][ i - 8 + part_width ];
80        return topright_ref;
81    }else{
82        tprintf(s->avctx, "topright MV not available\n");
83
84        *C= h->mv_cache[list][ i - 8 - 1 ];
85        return h->ref_cache[list][ i - 8 - 1 ];
86    }
87}
88
89/**
90 * gets the predicted MV.
91 * @param n the block index
92 * @param part_width the width of the partition (4, 8,16) -> (1, 2, 4)
93 * @param mx the x component of the predicted motion vector
94 * @param my the y component of the predicted motion vector
95 */
96static inline void pred_motion(H264Context * const h, int n, int part_width, int list, int ref, int * const mx, int * const my){
97    const int index8= scan8[n];
98    const int top_ref=      h->ref_cache[list][ index8 - 8 ];
99    const int left_ref=     h->ref_cache[list][ index8 - 1 ];
100    const int16_t * const A= h->mv_cache[list][ index8 - 1 ];
101    const int16_t * const B= h->mv_cache[list][ index8 - 8 ];
102    const int16_t * C;
103    int diagonal_ref, match_count;
104
105    assert(part_width==1 || part_width==2 || part_width==4);
106
107/* mv_cache
108  B . . A T T T T
109  U . . L . . , .
110  U . . L . . . .
111  U . . L . . , .
112  . . . L . . . .
113*/
114
115    diagonal_ref= fetch_diagonal_mv(h, &C, index8, list, part_width);
116    match_count= (diagonal_ref==ref) + (top_ref==ref) + (left_ref==ref);
117    tprintf(h->s.avctx, "pred_motion match_count=%d\n", match_count);
118    if(match_count > 1){ //most common
119        *mx= mid_pred(A[0], B[0], C[0]);
120        *my= mid_pred(A[1], B[1], C[1]);
121    }else if(match_count==1){
122        if(left_ref==ref){
123            *mx= A[0];
124            *my= A[1];
125        }else if(top_ref==ref){
126            *mx= B[0];
127            *my= B[1];
128        }else{
129            *mx= C[0];
130            *my= C[1];
131        }
132    }else{
133        if(top_ref == PART_NOT_AVAILABLE && diagonal_ref == PART_NOT_AVAILABLE && left_ref != PART_NOT_AVAILABLE){
134            *mx= A[0];
135            *my= A[1];
136        }else{
137            *mx= mid_pred(A[0], B[0], C[0]);
138            *my= mid_pred(A[1], B[1], C[1]);
139        }
140    }
141
142    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);
143}
144
145/**
146 * gets the directionally predicted 16x8 MV.
147 * @param n the block index
148 * @param mx the x component of the predicted motion vector
149 * @param my the y component of the predicted motion vector
150 */
151static inline void pred_16x8_motion(H264Context * const h, int n, int list, int ref, int * const mx, int * const my){
152    if(n==0){
153        const int top_ref=      h->ref_cache[list][ scan8[0] - 8 ];
154        const int16_t * const B= h->mv_cache[list][ scan8[0] - 8 ];
155
156        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);
157
158        if(top_ref == ref){
159            *mx= B[0];
160            *my= B[1];
161            return;
162        }
163    }else{
164        const int left_ref=     h->ref_cache[list][ scan8[8] - 1 ];
165        const int16_t * const A= h->mv_cache[list][ scan8[8] - 1 ];
166
167        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);
168
169        if(left_ref == ref){
170            *mx= A[0];
171            *my= A[1];
172            return;
173        }
174    }
175
176    //RARE
177    pred_motion(h, n, 4, list, ref, mx, my);
178}
179
180/**
181 * gets the directionally predicted 8x16 MV.
182 * @param n the block index
183 * @param mx the x component of the predicted motion vector
184 * @param my the y component of the predicted motion vector
185 */
186static inline void pred_8x16_motion(H264Context * const h, int n, int list, int ref, int * const mx, int * const my){
187    if(n==0){
188        const int left_ref=      h->ref_cache[list][ scan8[0] - 1 ];
189        const int16_t * const A=  h->mv_cache[list][ scan8[0] - 1 ];
190
191        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);
192
193        if(left_ref == ref){
194            *mx= A[0];
195            *my= A[1];
196            return;
197        }
198    }else{
199        const int16_t * C;
200        int diagonal_ref;
201
202        diagonal_ref= fetch_diagonal_mv(h, &C, scan8[4], list, 2);
203
204        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);
205
206        if(diagonal_ref == ref){
207            *mx= C[0];
208            *my= C[1];
209            return;
210        }
211    }
212
213    //RARE
214    pred_motion(h, n, 2, list, ref, mx, my);
215}
216
217static inline void pred_pskip_motion(H264Context * const h, int * const mx, int * const my){
218    const int top_ref = h->ref_cache[0][ scan8[0] - 8 ];
219    const int left_ref= h->ref_cache[0][ scan8[0] - 1 ];
220
221    tprintf(h->s.avctx, "pred_pskip: (%d) (%d) at %2d %2d\n", top_ref, left_ref, h->s.mb_x, h->s.mb_y);
222
223    if(top_ref == PART_NOT_AVAILABLE || left_ref == PART_NOT_AVAILABLE
224       || !( top_ref | AV_RN32A(h->mv_cache[0][ scan8[0] - 8 ]))
225       || !(left_ref | AV_RN32A(h->mv_cache[0][ scan8[0] - 1 ]))){
226
227        *mx = *my = 0;
228        return;
229    }
230
231    pred_motion(h, 0, 4, 0, 0, mx, my);
232
233    return;
234}
235
236#endif /* AVCODEC_H264_MVPRED_H */
237