motion_est.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

/*
 * Motion estimation
 * Copyright (c) 2000,2001 Fabrice Bellard.
 * Copyright (c) 2002-2004 Michael Niedermayer
 *
 * new motion estimation (X1/EPZS) by Michael Niedermayer <[e-mail]>
 *
 * 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 motion_est.c
 * Motion estimation.
 */

#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"

#undef NDEBUG
#include <assert.h>

#define SQ(a) ((a)*(a))

#define P_LEFT P[1]
#define P_TOP P[2]
#define P_TOPRIGHT P[3]
#define P_MEDIAN P[4]
#define P_MV1 P[9]

static inline int sad_hpel_motion_search(MpegEncContext * s,
                                  int *mx_ptr, int *my_ptr, int dmin,
                                  int src_index, int ref_index,
                                  int size, int h);

static inline int update_map_generation(MotionEstContext *c)
{
    c->map_generation+= 1<<(ME_MAP_MV_BITS*2);
    if(c->map_generation==0){
        c->map_generation= 1<<(ME_MAP_MV_BITS*2);
        memset(c->map, 0, sizeof(uint32_t)*ME_MAP_SIZE);
    }
    return c->map_generation;
}

/* shape adaptive search stuff */
typedef struct Minima{
    int height;
    int x, y;
    int checked;
}Minima;

static int minima_cmp(const void *a, const void *b){
    const Minima *da = (const Minima *) a;
    const Minima *db = (const Minima *) b;

    return da->height - db->height;
}

#define FLAG_QPEL   1 //must be 1
#define FLAG_CHROMA 2
#define FLAG_DIRECT 4

static inline void init_ref(MotionEstContext *c, uint8_t *src[3], uint8_t *ref[3], uint8_t *ref2[3], int x, int y, int ref_index){
    const int offset[3]= {
          y*c->  stride + x,
        ((y*c->uvstride + x)>>1),
        ((y*c->uvstride + x)>>1),
    };
    int i;
    for(i=0; i<3; i++){
        c->src[0][i]= src [i] + offset[i];
        c->ref[0][i]= ref [i] + offset[i];
    }
    if(ref_index){
        for(i=0; i<3; i++){
            c->ref[ref_index][i]= ref2[i] + offset[i];
        }
    }
}

static int get_flags(MotionEstContext *c, int direct, int chroma){
    return   ((c->avctx->flags&CODEC_FLAG_QPEL) ? FLAG_QPEL : 0)
           + (direct ? FLAG_DIRECT : 0)
           + (chroma ? FLAG_CHROMA : 0);
}

/*! \brief compares a block (either a full macroblock or a partition thereof)
    against a proposed motion-compensated prediction of that block
 */
static av_always_inline int cmp(MpegEncContext *s, const int x, const int y, const int subx, const int suby,
                      const int size, const int h, int ref_index, int src_index,
                      me_cmp_func cmp_func, me_cmp_func chroma_cmp_func, const int flags){
    MotionEstContext * const c= &s->me;
    const int stride= c->stride;
    const int uvstride= c->uvstride;
    const int qpel= flags&FLAG_QPEL;
    const int chroma= flags&FLAG_CHROMA;
    const int dxy= subx + (suby<<(1+qpel)); //FIXME log2_subpel?
    const int hx= subx + (x<<(1+qpel));
    const int hy= suby + (y<<(1+qpel));
    uint8_t * const * const ref= c->ref[ref_index];
    uint8_t * const * const src= c->src[src_index];
    int d;
    //FIXME check chroma 4mv, (no crashes ...)
    if(flags&FLAG_DIRECT){
        assert(x >= c->xmin && hx <= c->xmax<<(qpel+1) && y >= c->ymin && hy <= c->ymax<<(qpel+1));
        if(x >= c->xmin && hx <= c->xmax<<(qpel+1) && y >= c->ymin && hy <= c->ymax<<(qpel+1)){
            const int time_pp= s->pp_time;
            const int time_pb= s->pb_time;
            const int mask= 2*qpel+1;
            if(s->mv_type==MV_TYPE_8X8){
                int i;
                for(i=0; i<4; i++){
                    int fx = c->direct_basis_mv[i][0] + hx;
                    int fy = c->direct_basis_mv[i][1] + hy;
                    int bx = hx ? fx - c->co_located_mv[i][0] : c->co_located_mv[i][0]*(time_pb - time_pp)/time_pp + ((i &1)<<(qpel+4));
                    int by = hy ? fy - c->co_located_mv[i][1] : c->co_located_mv[i][1]*(time_pb - time_pp)/time_pp + ((i>>1)<<(qpel+4));
                    int fxy= (fx&mask) + ((fy&mask)<<(qpel+1));
                    int bxy= (bx&mask) + ((by&mask)<<(qpel+1));

                    uint8_t *dst= c->temp + 8*(i&1) + 8*stride*(i>>1);
                    if(qpel){
                        c->qpel_put[1][fxy](dst, ref[0] + (fx>>2) + (fy>>2)*stride, stride);
                        c->qpel_avg[1][bxy](dst, ref[8] + (bx>>2) + (by>>2)*stride, stride);
                    }else{
                        c->hpel_put[1][fxy](dst, ref[0] + (fx>>1) + (fy>>1)*stride, stride, 8);
                        c->hpel_avg[1][bxy](dst, ref[8] + (bx>>1) + (by>>1)*stride, stride, 8);
                    }
                }
            }else{
                int fx = c->direct_basis_mv[0][0] + hx;
                int fy = c->direct_basis_mv[0][1] + hy;
                int bx = hx ? fx - c->co_located_mv[0][0] : (c->co_located_mv[0][0]*(time_pb - time_pp)/time_pp);
                int by = hy ? fy - c->co_located_mv[0][1] : (c->co_located_mv[0][1]*(time_pb - time_pp)/time_pp);
                int fxy= (fx&mask) + ((fy&mask)<<(qpel+1));
                int bxy= (bx&mask) + ((by&mask)<<(qpel+1));

                if(qpel){
                    c->qpel_put[1][fxy](c->temp               , ref[0] + (fx>>2) + (fy>>2)*stride               , stride);
                    c->qpel_put[1][fxy](c->temp + 8           , ref[0] + (fx>>2) + (fy>>2)*stride + 8           , stride);
                    c->qpel_put[1][fxy](c->temp     + 8*stride, ref[0] + (fx>>2) + (fy>>2)*stride     + 8*stride, stride);
                    c->qpel_put[1][fxy](c->temp + 8 + 8*stride, ref[0] + (fx>>2) + (fy>>2)*stride + 8 + 8*stride, stride);
                    c->qpel_avg[1][bxy](c->temp               , ref[8] + (bx>>2) + (by>>2)*stride               , stride);
                    c->qpel_avg[1][bxy](c->temp + 8           , ref[8] + (bx>>2) + (by>>2)*stride + 8           , stride);
                    c->qpel_avg[1][bxy](c->temp     + 8*stride, ref[8] + (bx>>2) + (by>>2)*stride     + 8*stride, stride);
                    c->qpel_avg[1][bxy](c->temp + 8 + 8*stride, ref[8] + (bx>>2) + (by>>2)*stride + 8 + 8*stride, stride);
                }else{
                    assert((fx>>1) + 16*s->mb_x >= -16);
                    assert((fy>>1) + 16*s->mb_y >= -16);
                    assert((fx>>1) + 16*s->mb_x <= s->width);
                    assert((fy>>1) + 16*s->mb_y <= s->height);
                    assert((bx>>1) + 16*s->mb_x >= -16);
                    assert((by>>1) + 16*s->mb_y >= -16);
                    assert((bx>>1) + 16*s->mb_x <= s->width);
                    assert((by>>1) + 16*s->mb_y <= s->height);

                    c->hpel_put[0][fxy](c->temp, ref[0] + (fx>>1) + (fy>>1)*stride, stride, 16);
                    c->hpel_avg[0][bxy](c->temp, ref[8] + (bx>>1) + (by>>1)*stride, stride, 16);
                }
            }
            d = cmp_func(s, c->temp, src[0], stride, 16);
        }else
            d= 256*256*256*32;
    }else{
        int uvdxy;              /* no, it might not be used uninitialized */
        if(dxy){
            if(qpel){
                c->qpel_put[size][dxy](c->temp, ref[0] + x + y*stride, stride); //FIXME prototype (add h)
                if(chroma){
                    int cx= hx/2;
                    int cy= hy/2;
                    cx= (cx>>1)|(cx&1);
                    cy= (cy>>1)|(cy&1);
                    uvdxy= (cx&1) + 2*(cy&1);
                    //FIXME x/y wrong, but mpeg4 qpel is sick anyway, we should drop as much of it as possible in favor for h264
                }
            }else{
                c->hpel_put[size][dxy](c->temp, ref[0] + x + y*stride, stride, h);
                if(chroma)
                    uvdxy= dxy | (x&1) | (2*(y&1));
            }
            d = cmp_func(s, c->temp, src[0], stride, h);
        }else{
            d = cmp_func(s, src[0], ref[0] + x + y*stride, stride, h);
            if(chroma)
                uvdxy= (x&1) + 2*(y&1);
        }
        if(chroma){
            uint8_t * const uvtemp= c->temp + 16*stride;
            c->hpel_put[size+1][uvdxy](uvtemp  , ref[1] + (x>>1) + (y>>1)*uvstride, uvstride, h>>1);
            c->hpel_put[size+1][uvdxy](uvtemp+8, ref[2] + (x>>1) + (y>>1)*uvstride, uvstride, h>>1);
            d += chroma_cmp_func(s, uvtemp  , src[1], uvstride, h>>1);
            d += chroma_cmp_func(s, uvtemp+8, src[2], uvstride, h>>1);
        }
    }
#if 0
    if(full_pel){
        const int index= (((y)<<ME_MAP_SHIFT) + (x))&(ME_MAP_SIZE-1);
        score_map[index]= d;
    }

    d += (c->mv_penalty[hx - c->pred_x] + c->mv_penalty[hy - c->pred_y])*c->penalty_factor;
#endif
    return d;
}

#include "motion_est_template.c"

static int zero_cmp(void *s, uint8_t *a, uint8_t *b, int stride, int h){
    return 0;
}

static void zero_hpel(uint8_t *a, const uint8_t *b, int stride, int h){
}

void ff_init_me(MpegEncContext *s){
    MotionEstContext * const c= &s->me;
    int cache_size= FFMIN(ME_MAP_SIZE>>ME_MAP_SHIFT, 1<<ME_MAP_SHIFT);
    int dia_size= FFMAX(FFABS(s->avctx->dia_size)&255, FFABS(s->avctx->pre_dia_size)&255);
    c->avctx= s->avctx;

    if(cache_size < 2*dia_size && !c->stride){
        av_log(s->avctx, AV_LOG_INFO, "ME_MAP size may be a little small for the selected diamond size\n");
    }

    ff_set_cmp(&s->dsp, s->dsp.me_pre_cmp, c->avctx->me_pre_cmp);
    ff_set_cmp(&s->dsp, s->dsp.me_cmp, c->avctx->me_cmp);
    ff_set_cmp(&s->dsp, s->dsp.me_sub_cmp, c->avctx->me_sub_cmp);
    ff_set_cmp(&s->dsp, s->dsp.mb_cmp, c->avctx->mb_cmp);

    c->flags    = get_flags(c, 0, c->avctx->me_cmp    &FF_CMP_CHROMA);
    c->sub_flags= get_flags(c, 0, c->avctx->me_sub_cmp&FF_CMP_CHROMA);
    c->mb_flags = get_flags(c, 0, c->avctx->mb_cmp    &FF_CMP_CHROMA);

/*FIXME s->no_rounding b_type*/
    if(s->flags&CODEC_FLAG_QPEL){
        c->sub_motion_search= qpel_motion_search;
        c->qpel_avg= s->dsp.avg_qpel_pixels_tab;
        if(s->no_rounding) c->qpel_put= s->dsp.put_no_rnd_qpel_pixels_tab;
        else               c->qpel_put= s->dsp.put_qpel_pixels_tab;
    }else{
        if(c->avctx->me_sub_cmp&FF_CMP_CHROMA)
            c->sub_motion_search= hpel_motion_search;
        else if(   c->avctx->me_sub_cmp == FF_CMP_SAD
                && c->avctx->    me_cmp == FF_CMP_SAD
                && c->avctx->    mb_cmp == FF_CMP_SAD)
            c->sub_motion_search= sad_hpel_motion_search; // 2050 vs. 2450 cycles
        else
            c->sub_motion_search= hpel_motion_search;
    }
    c->hpel_avg= s->dsp.avg_pixels_tab;
    if(s->no_rounding) c->hpel_put= s->dsp.put_no_rnd_pixels_tab;
    else               c->hpel_put= s->dsp.put_pixels_tab;

    if(s->linesize){
        c->stride  = s->linesize;
        c->uvstride= s->uvlinesize;
    }else{
        c->stride  = 16*s->mb_width + 32;
        c->uvstride=  8*s->mb_width + 16;
    }

    /* 8x8 fullpel search would need a 4x4 chroma compare, which we do
     * not have yet, and even if we had, the motion estimation code
     * does not expect it. */
    if(s->codec_id != CODEC_ID_SNOW){
        if((c->avctx->me_cmp&FF_CMP_CHROMA)/* && !s->dsp.me_cmp[2]*/){
            s->dsp.me_cmp[2]= zero_cmp;
        }
        if((c->avctx->me_sub_cmp&FF_CMP_CHROMA) && !s->dsp.me_sub_cmp[2]){
            s->dsp.me_sub_cmp[2]= zero_cmp;
        }
        c->hpel_put[2][0]= c->hpel_put[2][1]=
        c->hpel_put[2][2]= c->hpel_put[2][3]= zero_hpel;
    }

    if(s->codec_id == CODEC_ID_H261){
        c->sub_motion_search= no_sub_motion_search;
    }

    c->temp= c->scratchpad;
}

#if 0
static int pix_dev(uint8_t * pix, int line_size, int mean)
{
    int s, i, j;

    s = 0;
    for (i = 0; i < 16; i++) {
        for (j = 0; j < 16; j += 8) {
            s += FFABS(pix[0]-mean);
            s += FFABS(pix[1]-mean);
            s += FFABS(pix[2]-mean);
            s += FFABS(pix[3]-mean);
            s += FFABS(pix[4]-mean);
            s += FFABS(pix[5]-mean);
            s += FFABS(pix[6]-mean);
            s += FFABS(pix[7]-mean);
            pix += 8;
        }
        pix += line_size - 16;
    }
    return s;
}
#endif

static inline void no_motion_search(MpegEncContext * s,
                                    int *mx_ptr, int *my_ptr)
{
    *mx_ptr = 16 * s->mb_x;
    *my_ptr = 16 * s->mb_y;
}

#if 0  /* the use of these functions is inside #if 0 */
static int full_motion_search(MpegEncContext * s,
                              int *mx_ptr, int *my_ptr, int range,
                              int xmin, int ymin, int xmax, int ymax, uint8_t *ref_picture)
{
    int x1, y1, x2, y2, xx, yy, x, y;
    int mx, my, dmin, d;
    uint8_t *pix;

    xx = 16 * s->mb_x;
    yy = 16 * s->mb_y;
    x1 = xx - range + 1;        /* we loose one pixel to avoid boundary pb with half pixel pred */
    if (x1 < xmin)
        x1 = xmin;
    x2 = xx + range - 1;
    if (x2 > xmax)
        x2 = xmax;
    y1 = yy - range + 1;
    if (y1 < ymin)
        y1 = ymin;
    y2 = yy + range - 1;
    if (y2 > ymax)
        y2 = ymax;