ffmpeg/libavcodec/h264_mvpred.h

/*
 * 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 av_always_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->f.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->f.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->f.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));
            }
            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 av_always_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 av_always_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 av_always_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);
}

#define FIX_MV_MBAFF(type, refn, mvn, idx)\
    if(FRAME_MBAFF){\
        if(MB_FIELD){\
            if(!IS_INTERLACED(type)){\
                refn <<= 1;\
                AV_COPY32(mvbuf[idx], mvn);\
                mvbuf[idx][1] /= 2;\
                mvn = mvbuf[idx];\
            }\
        }else{\
            if(IS_INTERLACED(type)){\
                refn >>= 1;\
                AV_COPY32(mvbuf[idx], mvn);\
                mvbuf[idx][1] <<= 1;\
                mvn = mvbuf[idx];\
            }\
        }\
    }

static av_always_inline void pred_pskip_motion(H264Context * const h){
    DECLARE_ALIGNED(4, static const int16_t, zeromv)[2] = {0};
    DECLARE_ALIGNED(4, int16_t, mvbuf)[3][2];
    MpegEncContext * const s = &h->s;
    int8_t *ref      = s->current_picture.f.ref_index[0];
    int16_t (*mv)[2] = s->current_picture.f.motion_val[0];
    int top_ref, left_ref, diagonal_ref, match_count, mx, my;
    const int16_t *A, *B, *C;
    int b_stride = h->b_stride;

    fill_rectangle(&h->ref_cache[0][scan8[0]], 4, 4, 8, 0, 1);

    /* To avoid doing an entire fill_decode_caches, we inline the relevant parts here.
     * FIXME: this is a partial duplicate of the logic in fill_decode_caches, but it's
     * faster this way.  Is there a way to avoid this duplication?
     */
    if(USES_LIST(h->left_type[LTOP], 0)){
        left_ref = ref[4*h->left_mb_xy[LTOP] + 1 + (h->left_block[0]&~1)];
        A = mv[h->mb2b_xy[h->left_mb_xy[LTOP]] + 3 + b_stride*h->left_block[0]];
        FIX_MV_MBAFF(h->left_type[LTOP], left_ref, A, 0);
        if(!(left_ref | AV_RN32A(A))){
            goto zeromv;
        }
    }else if(h->left_type[LTOP]){
        left_ref = LIST_NOT_USED;
        A = zeromv;
    }else{
        goto zeromv;
    }

    if(USES_LIST(h->top_type, 0)){
        top_ref = ref[4*h->top_mb_xy + 2];
        B = mv[h->mb2b_xy[h->top_mb_xy] + 3*b_stride];
        FIX_MV_MBAFF(h->top_type, top_ref, B, 1);
        if(!(top_ref | AV_RN32A(B))){
            goto zeromv;
        }
    }else if(h->top_type){
        top_ref = LIST_NOT_USED;
        B = zeromv;
    }else{
        goto zeromv;
    }

    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(USES_LIST(h->topright_type, 0)){
        diagonal_ref = ref[4*h->topright_mb_xy + 2];
        C = mv[h->mb2b_xy[h->topright_mb_xy] + 3*b_stride];
        FIX_MV_MBAFF(h->topright_type, diagonal_ref, C, 2);
    }else if(h->topright_type){
        diagonal_ref = LIST_NOT_USED;
        C = zeromv;
    }else{
        if(USES_LIST(h->topleft_type, 0)){
            diagonal_ref = ref[4*h->topleft_mb_xy + 1 + (h->topleft_partition & 2)];
            C = mv[h->mb2b_xy[h->topleft_mb_xy] + 3 + b_stride + (h->topleft_partition & 2*b_stride)];
            FIX_MV_MBAFF(h->topleft_type, diagonal_ref, C, 2);
        }else if(h->topleft_type){
            diagonal_ref = LIST_NOT_USED;
            C = zeromv;
        }else{
            diagonal_ref = PART_NOT_AVAILABLE;
            C = zeromv;
        }
    }

    match_count= !diagonal_ref + !top_ref + !left_ref;
    tprintf(h->s.avctx, "pred_pskip_motion match_count=%d\n", match_count);
    if(match_count > 1){
        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){
            mx = A[0];
            my = A[1];
        }else if(!top_ref){
            mx = B[0];
            my = B[1];
        }else{
            mx = C[0];
            my = C[1];
        }
    }else{
        mx = mid_pred(A[0], B[0], C[0]);
        my = mid_pred(A[1], B[1], C[1]);
    }

    fill_rectangle( h->mv_cache[0][scan8[0]], 4, 4, 8, pack16to32(mx,my), 4);
    return;
zeromv:
    fill_rectangle( h->mv_cache[0][scan8[0]], 4, 4, 8, 0, 4);
    return;
}

static void fill_decode_neighbors(H264Context *h, int mb_type){
    MpegEncContext * const s = &h->s;
    const int mb_xy= h->mb_xy;
    int topleft_xy, top_xy, topright_xy, left_xy[LEFT_MBS];
    static const uint8_t left_block_options[4][32]={
        {0,1,2,3,7,10,8,11,3+0*4, 3+1*4, 3+2*4, 3+3*4, 1+4*4, 1+8*4, 1+5*4, 1+9*4},
        {2,2,3,3,8,11,8,11,3+2*4, 3+2*4, 3+3*4, 3+3*4, 1+5*4, 1+9*4, 1+5*4, 1+9*4},
        {0,0,1,1,7,10,7,10,3+0*4, 3+0*4, 3+1*4, 3+1*4, 1+4*4, 1+8*4, 1+4*4, 1+8*4},
        {0,2,0,2,7,10,7,10,3+0*4, 3+2*4, 3+0*4, 3+2*4, 1+4*4, 1+8*4, 1+4*4, 1+8*4}
    };

    h->topleft_partition= -1;

    top_xy     = mb_xy  - (s->mb_stride << MB_FIELD);

    /* Wow, what a mess, why didn't they simplify the interlacing & intra
     * stuff, I can't imagine that these complex rules are worth it. */

    topleft_xy = top_xy - 1;
    topright_xy= top_xy + 1;
    left_xy[LBOT] = left_xy[LTOP] = mb_xy-1;
    h->left_block = left_block_options[0];
    if(FRAME_MBAFF){
        const int left_mb_field_flag = IS_INTERLACED(s->current_picture.f.mb_type[mb_xy - 1]);
        const int curr_mb_field_flag = IS_INTERLACED(mb_type);
        if(s->mb_y&1){
            if (left_mb_field_flag != curr_mb_field_flag) {
                left_xy[LBOT] = left_xy[LTOP] = mb_xy - s->mb_stride - 1;
                if (curr_mb_field_flag) {
                    left_xy[LBOT] += s->mb_stride;
                    h->left_block = left_block_options[3];
                } else {
                    topleft_xy += s->mb_stride;
                    // take top left mv from the middle of the mb, as opposed to all other modes which use the bottom right partition
                    h->topleft_partition = 0;
                    h->left_block = left_block_options[1];
                }
            }
        }else{
            if(curr_mb_field_flag){
                topleft_xy  += s->mb_stride & (((s->current_picture.f.mb_type[top_xy - 1] >> 7) & 1) - 1);
                topright_xy += s->mb_stride & (((s->current_picture.f.mb_type[top_xy + 1] >> 7) & 1) - 1);
                top_xy      += s->mb_stride & (((s->current_picture.f.mb_type[top_xy    ] >> 7) & 1) - 1);
            }
            if (left_mb_field_flag != curr_mb_field_flag) {
                if (curr_mb_field_flag) {
                    left_xy[LBOT] += s->mb_stride;
                    h->left_block = left_block_options[3];
                } else {
                    h->left_block = left_block_options[2];
                }
            }
        }
    }

    h->topleft_mb_xy = topleft_xy;
    h->top_mb_xy     = top_xy;
    h->topright_mb_xy= topright_xy;
    h->left_mb_xy[LTOP] = left_xy[LTOP];
    h->left_mb_xy[LBOT] = left_xy[LBOT];
    //FIXME do we need all in the context?

    h->topleft_type    = s->current_picture.f.mb_type[topleft_xy];
    h->top_type        = s->current_picture.f.mb_type[top_xy];
    h->topright_type   = s->current_picture.f.mb_type[topright_xy];
    h->left_type[LTOP] = s->current_picture.f.mb_type[left_xy[LTOP]];
    h->left_type[LBOT] = s->current_picture.f.mb_type[left_xy[LBOT]];

    if(FMO){
    if(h->slice_table[topleft_xy    ] != h->slice_num) h->topleft_type = 0;
    if(h->slice_table[top_xy        ] != h->slice_num) h->top_type     = 0;
    if(h->slice_table[left_xy[LTOP] ] != h->slice_num) h->left_type[LTOP] = h->left_type[LBOT] = 0;
    }else{
        if(h->slice_table[topleft_xy ] != h->slice_num){
            h->topleft_type = 0;
            if(h->slice_table[top_xy        ] != h->slice_num) h->top_type     = 0;
            if(h->slice_table[left_xy[LTOP] ] != h->slice_num) h->left_type[LTOP] = h->left_type[LBOT] = 0;
        }
    }
    if(h->slice_table[topright_xy] != h->slice_num) h->topright_type= 0;
}

static void fill_decode_caches(H264Context *h, int mb_type){
    MpegEncContext * const s = &h->s;
    int topleft_xy, top_xy, topright_xy, left_xy[LEFT_MBS];
    int topleft_type, top_type, topright_type, left_type[LEFT_MBS];
    const uint8_t * left_block= h->left_block;
    int i;
    uint8_t *nnz;
    uint8_t *nnz_cache;

    topleft_xy     = h->topleft_mb_xy;
    top_xy         = h->top_mb_xy;
    topright_xy    = h->topright_mb_xy;
    left_xy[LTOP]  = h->left_mb_xy[LTOP];
    left_xy[LBOT]  = h->left_mb_xy[LBOT];
    topleft_type   = h->topleft_type;
    top_type       = h->top_type;
    topright_type  = h->topright_type;
    left_type[LTOP]= h->left_type[LTOP];
    left_type[LBOT]= h->left_type[LBOT];

    if(!IS_SKIP(mb_type)){
        if(IS_INTRA(mb_type)){
            int type_mask= h->pps.constrained_intra_pred ? IS_INTRA(-1) : -1;
            h->topleft_samples_available=
            h->top_samples_available=
            h->left_samples_available= 0xFFFF;
            h->topright_samples_available= 0xEEEA;

            if(!(top_type & type_mask)){
                h->topleft_samples_available= 0xB3FF;
                h->top_samples_available= 0x33FF;
                h->topright_samples_available= 0x26EA;
            }
            if(IS_INTERLACED(mb_type) != IS_INTERLACED(left_type[LTOP])){
                if(IS_INTERLACED(mb_type)){
                    if(!(left_type[LTOP] & type_mask)){
                        h->topleft_samples_available&= 0xDFFF;
                        h->left_samples_available&= 0x5FFF;
                    }
                    if(!(left_type[LBOT] & type_mask)){
                        h->topleft_samples_available&= 0xFF5F;
                        h->left_samples_available&= 0xFF5F;
                    }
                }else{
                    int left_typei = s->current_picture.f.mb_type[left_xy[LTOP] + s->mb_stride];

                    assert(left_xy[LTOP] == left_xy[LBOT]);
                    if(!((left_typei & type_mask) && (left_type[LTOP] & type_mask))){
                        h->topleft_samples_available&= 0xDF5F;
                        h->left_samples_available&= 0x5F5F;
                    }
                }
            }else{
                if(!(left_type[LTOP] & type_mask)){
                    h->topleft_samples_available&= 0xDF5F;
                    h->left_samples_available&= 0x5F5F;
                }
            }

            if(!(topleft_type & type_mask))
                h->topleft_samples_available&= 0x7FFF;

            if(!(topright_type & type_mask))
                h->topright_samples_available&= 0xFBFF;

            if(IS_INTRA4x4(mb_type)){
                if(IS_INTRA4x4(top_type)){
                    AV_COPY32(h->intra4x4_pred_mode_cache+4+8*0, h->intra4x4_pred_mode + h->mb2br_xy[top_xy]);
                }else{
                    h->intra4x4_pred_mode_cache[4+8*0]=
                    h->intra4x4_pred_mode_cache[5+8*0]=
                    h->intra4x4_pred_mode_cache[6+8*0]=
                    h->intra4x4_pred_mode_cache[7+8*0]= 2 - 3*!(top_type & type_mask);
                }
                for(i=0; i<2; i++){
                    if(IS_INTRA4x4(left_type[LEFT(i)])){
                        int8_t *mode= h->intra4x4_pred_mode + h->mb2br_xy[left_xy[LEFT(i)]];
                        h->intra4x4_pred_mode_cache[3+8*1 + 2*8*i]= mode[6-left_block[0+2*i]];
                        h->intra4x4_pred_mode_cache[3+8*2 + 2*8*i]= mode[6-left_block[1+2*i]];
                    }else{
                        h->intra4x4_pred_mode_cache[3+8*1 + 2*8*i]=
                        h->intra4x4_pred_mode_cache[3+8*2 + 2*8*i]= 2 - 3*!(left_type[LEFT(i)] & type_mask);
                    }
                }
            }
        }


/*
0 . T T. T T T T
1 L . .L . . . .
2 L . .L . . . .
3 . T TL . . . .
4 L . .L . . . .
5 L . .. . . . .
*/
//FIXME constraint_intra_pred & partitioning & nnz (let us hope this is just a typo in the spec)
    nnz_cache = h->non_zero_count_cache;
    if(top_type){
        nnz = h->non_zero_count[top_xy];
        AV_COPY32(&nnz_cache[4+8* 0], &nnz[4*3]);
        if(CHROMA444){
            AV_COPY32(&nnz_cache[4+8* 5], &nnz[4* 7]);
            AV_COPY32(&nnz_cache[4+8*10], &nnz[4*11]);
        }else{
            AV_COPY32(&nnz_cache[4+8* 5], &nnz[4* 5]);
            AV_COPY32(&nnz_cache[4+8*10], &nnz[4* 9]);
        }
    }else{
        uint32_t top_empty = CABAC && !IS_INTRA(mb_type) ? 0 : 0x40404040;
        AV_WN32A(&nnz_cache[4+8* 0], top_empty);
        AV_WN32A(&nnz_cache[4+8* 5], top_empty);
        AV_WN32A(&nnz_cache[4+8*10], top_empty);
    }

    for (i=0; i<2; i++) {
        if(left_type[LEFT(i)]){
            nnz = h->non_zero_count[left_xy[LEFT(i)]];
            nnz_cache[3+8* 1 + 2*8*i]= nnz[left_block[8+0+2*i]];
            nnz_cache[3+8* 2 + 2*8*i]= nnz[left_block[8+1+2*i]];
            if(CHROMA444){
                nnz_cache[3+8* 6 + 2*8*i]= nnz[left_block[8+0+2*i]+4*4];
                nnz_cache[3+8* 7 + 2*8*i]= nnz[left_block[8+1+2*i]+4*4];
                nnz_cache[3+8*11 + 2*8*i]= nnz[left_block[8+0+2*i]+8*4];
                nnz_cache[3+8*12 + 2*8*i]= nnz[left_block[8+1+2*i]+8*4];
            }else{
                nnz_cache[3+8* 6 +   8*i]= nnz[left_block[8+4+2*i]];
                nnz_cache[3+8*11 +   8*i]= nnz[left_block[8+5+2*i]];
            }
        }else{
            nnz_cache[3+8* 1 + 2*8*i]=
            nnz_cache[3+8* 2 + 2*8*i]=
            nnz_cache[3+8* 6 + 2*8*i]=
            nnz_cache[3+8* 7 + 2*8*i]=
            nnz_cache[3+8*11 + 2*8*i]=
            nnz_cache[3+8*12 + 2*8*i]= CABAC && !IS_INTRA(mb_type) ? 0 : 64;
        }
    }

    if( CABAC ) {
        // top_cbp
        if(top_type) {
            h->top_cbp = h->cbp_table[top_xy];
        } else {
            h->top_cbp = IS_INTRA(mb_type) ? 0x7CF : 0x00F;
        }
        // left_cbp
        if (left_type[LTOP]) {
            h->left_cbp =   (h->cbp_table[left_xy[LTOP]] & 0x7F0)
                        |  ((h->cbp_table[left_xy[LTOP]]>>(left_block[0]&(~1)))&2)
                        | (((h->cbp_table[left_xy[LBOT]]>>(left_block[2]&(~1)))&2) << 2);
        } else {
            h->left_cbp = IS_INTRA(mb_type) ? 0x7CF : 0x00F;
        }
    }
    }

    if(IS_INTER(mb_type) || (IS_DIRECT(mb_type) && h->direct_spatial_mv_pred)){
        int list;
        int b_stride = h->b_stride;
        for(list=0; list<h->list_count; list++){
            int8_t *ref_cache = &h->ref_cache[list][scan8[0]];
            int8_t *ref       = s->current_picture.f.ref_index[list];
            int16_t (*mv_cache)[2] = &h->mv_cache[list][scan8[0]];
            int16_t (*mv)[2]       = s->current_picture.f.motion_val[list];
            if(!USES_LIST(mb_type, list)){
                continue;
            }
            assert(!(IS_DIRECT(mb_type) && !h->direct_spatial_mv_pred));

            if(USES_LIST(top_type, list)){
                const int b_xy= h->mb2b_xy[top_xy] + 3*b_stride;
                AV_COPY128(mv_cache[0 - 1*8], mv[b_xy + 0]);
                ref_cache[0 - 1*8]=
                ref_cache[1 - 1*8]= ref[4*top_xy + 2];
                ref_cache[2 - 1*8]=
                ref_cache[3 - 1*8]= ref[4*top_xy + 3];
            }else{
                AV_ZERO128(mv_cache[0 - 1*8]);
                AV_WN32A(&ref_cache[0 - 1*8], ((top_type ? LIST_NOT_USED : PART_NOT_AVAILABLE)&0xFF)*0x01010101);
            }

            if(mb_type & (MB_TYPE_16x8|MB_TYPE_8x8)){
            for(i=0; i<2; i++){
                int cache_idx = -1 + i*2*8;
                if(USES_LIST(left_type[LEFT(i)], list)){
                    const int b_xy= h->mb2b_xy[left_xy[LEFT(i)]] + 3;
                    const int b8_xy= 4*left_xy[LEFT(i)] + 1;
                    AV_COPY32(mv_cache[cache_idx  ], mv[b_xy + b_stride*left_block[0+i*2]]);
                    AV_COPY32(mv_cache[cache_idx+8], mv[b_xy + b_stride*left_block[1+i*2]]);
                    ref_cache[cache_idx  ]= ref[b8_xy + (left_block[0+i*2]&~1)];
                    ref_cache[cache_idx+8]= ref[b8_xy + (left_block[1+i*2]&~1)];
                }else{
                    AV_ZERO32(mv_cache[cache_idx  ]);
                    AV_ZERO32(mv_cache[cache_idx+8]);
                    ref_cache[cache_idx  ]=
                    ref_cache[cache_idx+8]= (left_type[LEFT(i)]) ? LIST_NOT_USED : PART_NOT_AVAILABLE;
                }
            }
            }else{
                if(USES_LIST(left_type[LTOP], list)){
                    const int b_xy= h->mb2b_xy[left_xy[LTOP]] + 3;
                    const int b8_xy= 4*left_xy[LTOP] + 1;
                    AV_COPY32(mv_cache[-1], mv[b_xy + b_stride*left_block[0]]);
                    ref_cache[-1]= ref[b8_xy + (left_block[0]&~1)];
                }else{
                    AV_ZERO32(mv_cache[-1]);
                    ref_cache[-1]= left_type[LTOP] ? LIST_NOT_USED : PART_NOT_AVAILABLE;
                }
            }

            if(USES_LIST(topright_type, list)){
                const int b_xy= h->mb2b_xy[topright_xy] + 3*b_stride;
                AV_COPY32(mv_cache[4 - 1*8], mv[b_xy]);
                ref_cache[4 - 1*8]= ref[4*topright_xy + 2];
            }else{
                AV_ZERO32(mv_cache[4 - 1*8]);
                ref_cache[4 - 1*8]= topright_type ? LIST_NOT_USED : PART_NOT_AVAILABLE;
            }
            if(ref_cache[4 - 1*8] < 0){
                if(USES_LIST(topleft_type, list)){
                    const int b_xy = h->mb2b_xy[topleft_xy] + 3 + b_stride + (h->topleft_partition & 2*b_stride);
                    const int b8_xy= 4*topleft_xy + 1 + (h->topleft_partition & 2);
                    AV_COPY32(mv_cache[-1 - 1*8], mv[b_xy]);
                    ref_cache[-1 - 1*8]= ref[b8_xy];
                }else{
                    AV_ZERO32(mv_cache[-1 - 1*8]);
                    ref_cache[-1 - 1*8]= topleft_type ? LIST_NOT_USED : PART_NOT_AVAILABLE;
                }
            }

            if((mb_type&(MB_TYPE_SKIP|MB_TYPE_DIRECT2)) && !FRAME_MBAFF)
                continue;

            if(!(mb_type&(MB_TYPE_SKIP|MB_TYPE_DIRECT2))){
                uint8_t (*mvd_cache)[2] = &h->mvd_cache[list][scan8[0]];
                uint8_t (*mvd)[2] = h->mvd_table[list];
                ref_cache[2+8*0] =
                ref_cache[2+8*2] = PART_NOT_AVAILABLE;
                AV_ZERO32(mv_cache[2+8*0]);
                AV_ZERO32(mv_cache[2+8*2]);

                if( CABAC ) {
                    if(USES_LIST(top_type, list)){
                        const int b_xy= h->mb2br_xy[top_xy];
                        AV_COPY64(mvd_cache[0 - 1*8], mvd[b_xy + 0]);
                    }else{
                        AV_ZERO64(mvd_cache[0 - 1*8]);
                    }
                    if(USES_LIST(left_type[LTOP], list)){
                        const int b_xy= h->mb2br_xy[left_xy[LTOP]] + 6;
                        AV_COPY16(mvd_cache[-1 + 0*8], mvd[b_xy - left_block[0]]);
                        AV_COPY16(mvd_cache[-1 + 1*8], mvd[b_xy - left_block[1]]);
                    }else{
                        AV_ZERO16(mvd_cache[-1 + 0*8]);
                        AV_ZERO16(mvd_cache[-1 + 1*8]);
                    }
                    if(USES_LIST(left_type[LBOT], list)){
                        const int b_xy= h->mb2br_xy[left_xy[LBOT]] + 6;
                        AV_COPY16(mvd_cache[-1 + 2*8], mvd[b_xy - left_block[2]]);
                        AV_COPY16(mvd_cache[-1 + 3*8], mvd[b_xy - left_block[3]]);
                    }else{
                        AV_ZERO16(mvd_cache[-1 + 2*8]);
                        AV_ZERO16(mvd_cache[-1 + 3*8]);
                    }
                    AV_ZERO16(mvd_cache[2+8*0]);
                    AV_ZERO16(mvd_cache[2+8*2]);
                    if(h->slice_type_nos == AV_PICTURE_TYPE_B){
                        uint8_t *direct_cache = &h->direct_cache[scan8[0]];
                        uint8_t *direct_table = h->direct_table;
                        fill_rectangle(direct_cache, 4, 4, 8, MB_TYPE_16x16>>1, 1);

                        if(IS_DIRECT(top_type)){
                            AV_WN32A(&direct_cache[-1*8], 0x01010101u*(MB_TYPE_DIRECT2>>1));
                        }else if(IS_8X8(top_type)){
                            int b8_xy = 4*top_xy;
                            direct_cache[0 - 1*8]= direct_table[b8_xy + 2];
                            direct_cache[2 - 1*8]= direct_table[b8_xy + 3];
                        }else{
                            AV_WN32A(&direct_cache[-1*8], 0x01010101*(MB_TYPE_16x16>>1));
                        }

                        if(IS_DIRECT(left_type[LTOP]))
                            direct_cache[-1 + 0*8]= MB_TYPE_DIRECT2>>1;
                        else if(IS_8X8(left_type[LTOP]))
                            direct_cache[-1 + 0*8]= direct_table[4*left_xy[LTOP] + 1 + (left_block[0]&~1)];
                        else
                            direct_cache[-1 + 0*8]= MB_TYPE_16x16>>1;

                        if(IS_DIRECT(left_type[LBOT]))
                            direct_cache[-1 + 2*8]= MB_TYPE_DIRECT2>>1;
                        else if(IS_8X8(left_type[LBOT]))
                            direct_cache[-1 + 2*8]= direct_table[4*left_xy[LBOT] + 1 + (left_block[2]&~1)];
                        else
                            direct_cache[-1 + 2*8]= MB_TYPE_16x16>>1;
                    }
                }
            }
            if(FRAME_MBAFF){
#define MAP_MVS\
                    MAP_F2F(scan8[0] - 1 - 1*8, topleft_type)\
                    MAP_F2F(scan8[0] + 0 - 1*8, top_type)\
                    MAP_F2F(scan8[0] + 1 - 1*8, top_type)\
                    MAP_F2F(scan8[0] + 2 - 1*8, top_type)\
                    MAP_F2F(scan8[0] + 3 - 1*8, top_type)\
                    MAP_F2F(scan8[0] + 4 - 1*8, topright_type)\
                    MAP_F2F(scan8[0] - 1 + 0*8, left_type[LTOP])\
                    MAP_F2F(scan8[0] - 1 + 1*8, left_type[LTOP])\
                    MAP_F2F(scan8[0] - 1 + 2*8, left_type[LBOT])\
                    MAP_F2F(scan8[0] - 1 + 3*8, left_type[LBOT])
                if(MB_FIELD){
#define MAP_F2F(idx, mb_type)\
                    if(!IS_INTERLACED(mb_type) && h->ref_cache[list][idx] >= 0){\
                        h->ref_cache[list][idx] <<= 1;\
                        h->mv_cache[list][idx][1] /= 2;\
                        h->mvd_cache[list][idx][1] >>=1;\
                    }
                    MAP_MVS
#undef MAP_F2F
                }else{
#define MAP_F2F(idx, mb_type)\
                    if(IS_INTERLACED(mb_type) && h->ref_cache[list][idx] >= 0){\
                        h->ref_cache[list][idx] >>= 1;\
                        h->mv_cache[list][idx][1] <<= 1;\
                        h->mvd_cache[list][idx][1] <<= 1;\
                    }
                    MAP_MVS
#undef MAP_F2F
                }
            }
        }
    }

        h->neighbor_transform_size= !!IS_8x8DCT(top_type) + !!IS_8x8DCT(left_type[LTOP]);
}

/**
 * decodes a P_SKIP or B_SKIP macroblock
 */
static void av_unused decode_mb_skip(H264Context *h){
    MpegEncContext * const s = &h->s;
    const int mb_xy= h->mb_xy;
    int mb_type=0;

    memset(h->non_zero_count[mb_xy], 0, 48);

    if(MB_FIELD)
        mb_type|= MB_TYPE_INTERLACED;

    if( h->slice_type_nos == AV_PICTURE_TYPE_B )
    {
        // just for fill_caches. pred_direct_motion will set the real mb_type
        mb_type|= MB_TYPE_L0L1|MB_TYPE_DIRECT2|MB_TYPE_SKIP;
        if(h->direct_spatial_mv_pred){
            fill_decode_neighbors(h, mb_type);
        fill_decode_caches(h, mb_type); //FIXME check what is needed and what not ...
        }
        ff_h264_pred_direct_motion(h, &mb_type);
        mb_type|= MB_TYPE_SKIP;
    }
    else
    {
        mb_type|= MB_TYPE_16x16|MB_TYPE_P0L0|MB_TYPE_P1L0|MB_TYPE_SKIP;

        fill_decode_neighbors(h, mb_type);
        pred_pskip_motion(h);
    }

    write_back_motion(h, mb_type);
    s->current_picture.f.mb_type[mb_xy]      = mb_type;
    s->current_picture.f.qscale_table[mb_xy] = s->qscale;
    h->slice_table[ mb_xy ]= h->slice_num;
    h->prev_mb_skipped= 1;
}

#endif /* AVCODEC_H264_MVPRED_H */