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ffmpeg / libavcodec / h264_mvpred.h @ aa5ee59e

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/*
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 * H.26L/H.264/AVC/JVT/14496-10/... motion vector predicion
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 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file libavcodec/h264_mvpred.h
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 * H.264 / AVC / MPEG4 part10 motion vector predicion.
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 * @author Michael Niedermayer <michaelni@gmx.at>
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 */
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#ifndef AVCODEC_H264_MVPRED_H
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#define AVCODEC_H264_MVPRED_H
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#include "internal.h"
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#include "avcodec.h"
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#include "h264.h"
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//#undef NDEBUG
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#include <assert.h>
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static inline int fetch_diagonal_mv(H264Context *h, const int16_t **C, int i, int list, int part_width){
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    const int topright_ref= h->ref_cache[list][ i - 8 + part_width ];
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    MpegEncContext *s = &h->s;
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    /* there is no consistent mapping of mvs to neighboring locations that will
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     * make mbaff happy, so we can't move all this logic to fill_caches */
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    if(FRAME_MBAFF){
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#define SET_DIAG_MV(MV_OP, REF_OP, XY, Y4)\
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                const int xy = XY, y4 = Y4;\
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                const int mb_type = mb_types[xy+(y4>>2)*s->mb_stride];\
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                if(!USES_LIST(mb_type,list))\
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                    return LIST_NOT_USED;\
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                mv = s->current_picture_ptr->motion_val[list][h->mb2b_xy[xy]+3 + y4*h->b_stride];\
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                h->mv_cache[list][scan8[0]-2][0] = mv[0];\
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                h->mv_cache[list][scan8[0]-2][1] = mv[1] MV_OP;\
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                return s->current_picture_ptr->ref_index[list][4*xy+1 + (y4&~1)] REF_OP;
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        if(topright_ref == PART_NOT_AVAILABLE
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           && i >= scan8[0]+8 && (i&7)==4
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           && h->ref_cache[list][scan8[0]-1] != PART_NOT_AVAILABLE){
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            const uint32_t *mb_types = s->current_picture_ptr->mb_type;
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            const int16_t *mv;
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            AV_ZERO32(h->mv_cache[list][scan8[0]-2]);
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            *C = h->mv_cache[list][scan8[0]-2];
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            if(!MB_FIELD
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               && IS_INTERLACED(h->left_type[0])){
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                SET_DIAG_MV(*2, >>1, h->left_mb_xy[0]+s->mb_stride, (s->mb_y&1)*2+(i>>5));
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                assert(h->left_mb_xy[0] == h->left_mb_xy[1]);
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            }
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            if(MB_FIELD
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               && !IS_INTERLACED(h->left_type[0])){
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                // left shift will turn LIST_NOT_USED into PART_NOT_AVAILABLE, but that's OK.
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                SET_DIAG_MV(/2, <<1, h->left_mb_xy[i>=36], ((i>>2))&3);
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            }
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        }
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#undef SET_DIAG_MV
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    }
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    if(topright_ref != PART_NOT_AVAILABLE){
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        *C= h->mv_cache[list][ i - 8 + part_width ];
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        return topright_ref;
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    }else{
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        tprintf(s->avctx, "topright MV not available\n");
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        *C= h->mv_cache[list][ i - 8 - 1 ];
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        return h->ref_cache[list][ i - 8 - 1 ];
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    }
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}
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/**
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 * gets the predicted MV.
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 * @param n the block index
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 * @param part_width the width of the partition (4, 8,16) -> (1, 2, 4)
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 * @param mx the x component of the predicted motion vector
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 * @param my the y component of the predicted motion vector
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 */
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static inline void pred_motion(H264Context * const h, int n, int part_width, int list, int ref, int * const mx, int * const my){
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    const int index8= scan8[n];
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    const int top_ref=      h->ref_cache[list][ index8 - 8 ];
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    const int left_ref=     h->ref_cache[list][ index8 - 1 ];
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    const int16_t * const A= h->mv_cache[list][ index8 - 1 ];
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    const int16_t * const B= h->mv_cache[list][ index8 - 8 ];
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    const int16_t * C;
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    int diagonal_ref, match_count;
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    assert(part_width==1 || part_width==2 || part_width==4);
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/* mv_cache
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  B . . A T T T T
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  U . . L . . , .
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  U . . L . . . .
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  U . . L . . , .
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  . . . L . . . .
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*/
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    diagonal_ref= fetch_diagonal_mv(h, &C, index8, list, part_width);
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    match_count= (diagonal_ref==ref) + (top_ref==ref) + (left_ref==ref);
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    tprintf(h->s.avctx, "pred_motion match_count=%d\n", match_count);
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    if(match_count > 1){ //most common
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        *mx= mid_pred(A[0], B[0], C[0]);
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        *my= mid_pred(A[1], B[1], C[1]);
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    }else if(match_count==1){
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        if(left_ref==ref){
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            *mx= A[0];
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            *my= A[1];
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        }else if(top_ref==ref){
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            *mx= B[0];
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            *my= B[1];
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        }else{
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            *mx= C[0];
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            *my= C[1];
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        }
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    }else{
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        if(top_ref == PART_NOT_AVAILABLE && diagonal_ref == PART_NOT_AVAILABLE && left_ref != PART_NOT_AVAILABLE){
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            *mx= A[0];
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            *my= A[1];
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        }else{
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            *mx= mid_pred(A[0], B[0], C[0]);
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            *my= mid_pred(A[1], B[1], C[1]);
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        }
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    }
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    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);
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}
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/**
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 * gets the directionally predicted 16x8 MV.
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 * @param n the block index
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 * @param mx the x component of the predicted motion vector
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 * @param my the y component of the predicted motion vector
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 */
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static inline void pred_16x8_motion(H264Context * const h, int n, int list, int ref, int * const mx, int * const my){
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    if(n==0){
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        const int top_ref=      h->ref_cache[list][ scan8[0] - 8 ];
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        const int16_t * const B= h->mv_cache[list][ scan8[0] - 8 ];
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        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);
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        if(top_ref == ref){
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            *mx= B[0];
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            *my= B[1];
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            return;
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        }
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    }else{
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        const int left_ref=     h->ref_cache[list][ scan8[8] - 1 ];
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        const int16_t * const A= h->mv_cache[list][ scan8[8] - 1 ];
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        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);
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        if(left_ref == ref){
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            *mx= A[0];
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            *my= A[1];
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            return;
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        }
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    }
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    //RARE
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    pred_motion(h, n, 4, list, ref, mx, my);
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}
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/**
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 * gets the directionally predicted 8x16 MV.
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 * @param n the block index
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 * @param mx the x component of the predicted motion vector
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 * @param my the y component of the predicted motion vector
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 */
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static inline void pred_8x16_motion(H264Context * const h, int n, int list, int ref, int * const mx, int * const my){
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    if(n==0){
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        const int left_ref=      h->ref_cache[list][ scan8[0] - 1 ];
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        const int16_t * const A=  h->mv_cache[list][ scan8[0] - 1 ];
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        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);
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        if(left_ref == ref){
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            *mx= A[0];
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            *my= A[1];
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            return;
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        }
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    }else{
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        const int16_t * C;
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        int diagonal_ref;
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        diagonal_ref= fetch_diagonal_mv(h, &C, scan8[4], list, 2);
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        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);
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        if(diagonal_ref == ref){
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            *mx= C[0];
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            *my= C[1];
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            return;
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        }
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    }
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    //RARE
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    pred_motion(h, n, 2, list, ref, mx, my);
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}
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static inline void pred_pskip_motion(H264Context * const h, int * const mx, int * const my){
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    const int top_ref = h->ref_cache[0][ scan8[0] - 8 ];
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    const int left_ref= h->ref_cache[0][ scan8[0] - 1 ];
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    tprintf(h->s.avctx, "pred_pskip: (%d) (%d) at %2d %2d\n", top_ref, left_ref, h->s.mb_x, h->s.mb_y);
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    if(top_ref == PART_NOT_AVAILABLE || left_ref == PART_NOT_AVAILABLE
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       || !( top_ref | AV_RN32A(h->mv_cache[0][ scan8[0] - 8 ]))
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       || !(left_ref | AV_RN32A(h->mv_cache[0][ scan8[0] - 1 ]))){
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        *mx = *my = 0;
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        return;
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    }
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    pred_motion(h, 0, 4, 0, 0, mx, my);
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    return;
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}
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#endif /* AVCODEC_H264_MVPRED_H */