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ffmpeg / libavcodec / mpeg4video.c @ 2912e87a

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/*
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 * MPEG4 decoder / encoder common code.
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 * Copyright (c) 2000,2001 Fabrice Bellard
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 * Copyright (c) 2002-2010 Michael Niedermayer <michaelni@gmx.at>
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 *
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 * This file is part of Libav.
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 *
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 * Libav 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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 * Libav 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 Libav; 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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#include "mpegvideo.h"
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#include "mpeg4video.h"
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#include "mpeg4data.h"
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uint8_t ff_mpeg4_static_rl_table_store[3][2][2*MAX_RUN + MAX_LEVEL + 3];
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int ff_mpeg4_get_video_packet_prefix_length(MpegEncContext *s){
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    switch(s->pict_type){
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        case FF_I_TYPE:
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            return 16;
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        case FF_P_TYPE:
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        case FF_S_TYPE:
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            return s->f_code+15;
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        case FF_B_TYPE:
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            return FFMAX3(s->f_code, s->b_code, 2) + 15;
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        default:
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            return -1;
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    }
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}
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void ff_mpeg4_clean_buffers(MpegEncContext *s)
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{
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    int c_wrap, c_xy, l_wrap, l_xy;
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    l_wrap= s->b8_stride;
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    l_xy= (2*s->mb_y-1)*l_wrap + s->mb_x*2 - 1;
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    c_wrap= s->mb_stride;
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    c_xy= (s->mb_y-1)*c_wrap + s->mb_x - 1;
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#if 0
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    /* clean DC */
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    memsetw(s->dc_val[0] + l_xy, 1024, l_wrap*2+1);
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    memsetw(s->dc_val[1] + c_xy, 1024, c_wrap+1);
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    memsetw(s->dc_val[2] + c_xy, 1024, c_wrap+1);
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#endif
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    /* clean AC */
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    memset(s->ac_val[0] + l_xy, 0, (l_wrap*2+1)*16*sizeof(int16_t));
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    memset(s->ac_val[1] + c_xy, 0, (c_wrap  +1)*16*sizeof(int16_t));
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    memset(s->ac_val[2] + c_xy, 0, (c_wrap  +1)*16*sizeof(int16_t));
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    /* clean MV */
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    // we can't clear the MVs as they might be needed by a b frame
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//    memset(s->motion_val + l_xy, 0, (l_wrap*2+1)*2*sizeof(int16_t));
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//    memset(s->motion_val, 0, 2*sizeof(int16_t)*(2 + s->mb_width*2)*(2 + s->mb_height*2));
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    s->last_mv[0][0][0]=
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    s->last_mv[0][0][1]=
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    s->last_mv[1][0][0]=
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    s->last_mv[1][0][1]= 0;
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}
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#define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
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#define tab_bias (tab_size/2)
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//used by mpeg4 and rv10 decoder
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void ff_mpeg4_init_direct_mv(MpegEncContext *s){
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    int i;
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    for(i=0; i<tab_size; i++){
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        s->direct_scale_mv[0][i] = (i-tab_bias)*s->pb_time/s->pp_time;
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        s->direct_scale_mv[1][i] = (i-tab_bias)*(s->pb_time-s->pp_time)/s->pp_time;
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    }
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}
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static inline void ff_mpeg4_set_one_direct_mv(MpegEncContext *s, int mx, int my, int i){
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    int xy= s->block_index[i];
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    uint16_t time_pp= s->pp_time;
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    uint16_t time_pb= s->pb_time;
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    int p_mx, p_my;
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    p_mx= s->next_picture.motion_val[0][xy][0];
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    if((unsigned)(p_mx + tab_bias) < tab_size){
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        s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias] + mx;
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        s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
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                            : s->direct_scale_mv[1][p_mx + tab_bias];
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    }else{
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        s->mv[0][i][0] = p_mx*time_pb/time_pp + mx;
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        s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
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                            : p_mx*(time_pb - time_pp)/time_pp;
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    }
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    p_my= s->next_picture.motion_val[0][xy][1];
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    if((unsigned)(p_my + tab_bias) < tab_size){
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        s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias] + my;
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        s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
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                            : s->direct_scale_mv[1][p_my + tab_bias];
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    }else{
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        s->mv[0][i][1] = p_my*time_pb/time_pp + my;
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        s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
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                            : p_my*(time_pb - time_pp)/time_pp;
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    }
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}
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#undef tab_size
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#undef tab_bias
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/**
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 *
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 * @return the mb_type
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 */
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int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my){
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    const int mb_index= s->mb_x + s->mb_y*s->mb_stride;
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    const int colocated_mb_type= s->next_picture.mb_type[mb_index];
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    uint16_t time_pp;
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    uint16_t time_pb;
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    int i;
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    //FIXME avoid divides
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    // try special case with shifts for 1 and 3 B-frames?
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    if(IS_8X8(colocated_mb_type)){
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        s->mv_type = MV_TYPE_8X8;
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        for(i=0; i<4; i++){
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            ff_mpeg4_set_one_direct_mv(s, mx, my, i);
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        }
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        return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
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    } else if(IS_INTERLACED(colocated_mb_type)){
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        s->mv_type = MV_TYPE_FIELD;
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        for(i=0; i<2; i++){
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            int field_select= s->next_picture.ref_index[0][4*mb_index + 2*i];
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            s->field_select[0][i]= field_select;
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            s->field_select[1][i]= i;
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            if(s->top_field_first){
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                time_pp= s->pp_field_time - field_select + i;
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                time_pb= s->pb_field_time - field_select + i;
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            }else{
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                time_pp= s->pp_field_time + field_select - i;
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                time_pb= s->pb_field_time + field_select - i;
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            }
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            s->mv[0][i][0] = s->p_field_mv_table[i][0][mb_index][0]*time_pb/time_pp + mx;
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            s->mv[0][i][1] = s->p_field_mv_table[i][0][mb_index][1]*time_pb/time_pp + my;
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            s->mv[1][i][0] = mx ? s->mv[0][i][0] - s->p_field_mv_table[i][0][mb_index][0]
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                                : s->p_field_mv_table[i][0][mb_index][0]*(time_pb - time_pp)/time_pp;
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            s->mv[1][i][1] = my ? s->mv[0][i][1] - s->p_field_mv_table[i][0][mb_index][1]
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                                : s->p_field_mv_table[i][0][mb_index][1]*(time_pb - time_pp)/time_pp;
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        }
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        return MB_TYPE_DIRECT2 | MB_TYPE_16x8 | MB_TYPE_L0L1 | MB_TYPE_INTERLACED;
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    }else{
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        ff_mpeg4_set_one_direct_mv(s, mx, my, 0);
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        s->mv[0][1][0] = s->mv[0][2][0] = s->mv[0][3][0] = s->mv[0][0][0];
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        s->mv[0][1][1] = s->mv[0][2][1] = s->mv[0][3][1] = s->mv[0][0][1];
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        s->mv[1][1][0] = s->mv[1][2][0] = s->mv[1][3][0] = s->mv[1][0][0];
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        s->mv[1][1][1] = s->mv[1][2][1] = s->mv[1][3][1] = s->mv[1][0][1];
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        if((s->avctx->workaround_bugs & FF_BUG_DIRECT_BLOCKSIZE) || !s->quarter_sample)
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            s->mv_type= MV_TYPE_16X16;
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        else
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            s->mv_type= MV_TYPE_8X8;
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        return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1; //Note see prev line
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    }
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}
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