libavcodec/mpeg4video.c

   1 /*
   2  * MPEG4 decoder / encoder common code.
   3  * Copyright (c) 2000,2001 Fabrice Bellard
   4  * Copyright (c) 2002-2010 Michael Niedermayer <michaelni@gmx.at>
   5  *
   6  * This file is part of Libav.
   7  *
   8  * Libav is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * Libav is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with Libav; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include "mpegvideo.h"
  24 #include "mpeg4video.h"
  25 #include "mpeg4data.h"
  26
  27 uint8_t ff_mpeg4_static_rl_table_store[3][2][2*MAX_RUN + MAX_LEVEL + 3];
  28
  29 int ff_mpeg4_get_video_packet_prefix_length(MpegEncContext *s){
  30     switch(s->pict_type){
  31         case AV_PICTURE_TYPE_I:
  32             return 16;
  33         case AV_PICTURE_TYPE_P:
  34         case AV_PICTURE_TYPE_S:
  35             return s->f_code+15;
  36         case AV_PICTURE_TYPE_B:
  37             return FFMAX3(s->f_code, s->b_code, 2) + 15;
  38         default:
  39             return -1;
  40     }
  41 }
  42
  43 void ff_mpeg4_clean_buffers(MpegEncContext *s)
  44 {
  45     int c_wrap, c_xy, l_wrap, l_xy;
  46
  47     l_wrap= s->b8_stride;
  48     l_xy= (2*s->mb_y-1)*l_wrap + s->mb_x*2 - 1;
  49     c_wrap= s->mb_stride;
  50     c_xy= (s->mb_y-1)*c_wrap + s->mb_x - 1;
  51
  52 #if 0
  53     /* clean DC */
  54     memsetw(s->dc_val[0] + l_xy, 1024, l_wrap*2+1);
  55     memsetw(s->dc_val[1] + c_xy, 1024, c_wrap+1);
  56     memsetw(s->dc_val[2] + c_xy, 1024, c_wrap+1);
  57 #endif
  58
  59     /* clean AC */
  60     memset(s->ac_val[0] + l_xy, 0, (l_wrap*2+1)*16*sizeof(int16_t));
  61     memset(s->ac_val[1] + c_xy, 0, (c_wrap  +1)*16*sizeof(int16_t));
  62     memset(s->ac_val[2] + c_xy, 0, (c_wrap  +1)*16*sizeof(int16_t));
  63
  64     /* clean MV */
  65     // we can't clear the MVs as they might be needed by a b frame
  66 //    memset(s->motion_val + l_xy, 0, (l_wrap*2+1)*2*sizeof(int16_t));
  67 //    memset(s->motion_val, 0, 2*sizeof(int16_t)*(2 + s->mb_width*2)*(2 + s->mb_height*2));
  68     s->last_mv[0][0][0]=
  69     s->last_mv[0][0][1]=
  70     s->last_mv[1][0][0]=
  71     s->last_mv[1][0][1]= 0;
  72 }
  73
  74 #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
  75 #define tab_bias (tab_size/2)
  76
  77 //used by mpeg4 and rv10 decoder
  78 void ff_mpeg4_init_direct_mv(MpegEncContext *s){
  79     int i;
  80     for(i=0; i<tab_size; i++){
  81         s->direct_scale_mv[0][i] = (i-tab_bias)*s->pb_time/s->pp_time;
  82         s->direct_scale_mv[1][i] = (i-tab_bias)*(s->pb_time-s->pp_time)/s->pp_time;
  83     }
  84 }
  85
  86 static inline void ff_mpeg4_set_one_direct_mv(MpegEncContext *s, int mx, int my, int i){
  87     int xy= s->block_index[i];
  88     uint16_t time_pp= s->pp_time;
  89     uint16_t time_pb= s->pb_time;
  90     int p_mx, p_my;
  91
  92     p_mx = s->next_picture.f.motion_val[0][xy][0];
  93     if((unsigned)(p_mx + tab_bias) < tab_size){
  94         s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias] + mx;
  95         s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
  96                             : s->direct_scale_mv[1][p_mx + tab_bias];
  97     }else{
  98         s->mv[0][i][0] = p_mx*time_pb/time_pp + mx;
  99         s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
 100                             : p_mx*(time_pb - time_pp)/time_pp;
 101     }
 102     p_my = s->next_picture.f.motion_val[0][xy][1];
 103     if((unsigned)(p_my + tab_bias) < tab_size){
 104         s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias] + my;
 105         s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
 106                             : s->direct_scale_mv[1][p_my + tab_bias];
 107     }else{
 108         s->mv[0][i][1] = p_my*time_pb/time_pp + my;
 109         s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
 110                             : p_my*(time_pb - time_pp)/time_pp;
 111     }
 112 }
 113
 114 #undef tab_size
 115 #undef tab_bias
 116
 117 /**
 118  *
 119  * @return the mb_type
 120  */
 121 int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my){
 122     const int mb_index= s->mb_x + s->mb_y*s->mb_stride;
 123     const int colocated_mb_type = s->next_picture.f.mb_type[mb_index];
 124     uint16_t time_pp;
 125     uint16_t time_pb;
 126     int i;
 127
 128     //FIXME avoid divides
 129     // try special case with shifts for 1 and 3 B-frames?
 130
 131     if(IS_8X8(colocated_mb_type)){
 132         s->mv_type = MV_TYPE_8X8;
 133         for(i=0; i<4; i++){
 134             ff_mpeg4_set_one_direct_mv(s, mx, my, i);
 135         }
 136         return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
 137     } else if(IS_INTERLACED(colocated_mb_type)){
 138         s->mv_type = MV_TYPE_FIELD;
 139         for(i=0; i<2; i++){
 140             int field_select = s->next_picture.f.ref_index[0][4 * mb_index + 2 * i];
 141             s->field_select[0][i]= field_select;
 142             s->field_select[1][i]= i;
 143             if(s->top_field_first){
 144                 time_pp= s->pp_field_time - field_select + i;
 145                 time_pb= s->pb_field_time - field_select + i;
 146             }else{
 147                 time_pp= s->pp_field_time + field_select - i;
 148                 time_pb= s->pb_field_time + field_select - i;
 149             }
 150             s->mv[0][i][0] = s->p_field_mv_table[i][0][mb_index][0]*time_pb/time_pp + mx;
 151             s->mv[0][i][1] = s->p_field_mv_table[i][0][mb_index][1]*time_pb/time_pp + my;
 152             s->mv[1][i][0] = mx ? s->mv[0][i][0] - s->p_field_mv_table[i][0][mb_index][0]
 153                                 : s->p_field_mv_table[i][0][mb_index][0]*(time_pb - time_pp)/time_pp;
 154             s->mv[1][i][1] = my ? s->mv[0][i][1] - s->p_field_mv_table[i][0][mb_index][1]
 155                                 : s->p_field_mv_table[i][0][mb_index][1]*(time_pb - time_pp)/time_pp;
 156         }
 157         return MB_TYPE_DIRECT2 | MB_TYPE_16x8 | MB_TYPE_L0L1 | MB_TYPE_INTERLACED;
 158     }else{
 159         ff_mpeg4_set_one_direct_mv(s, mx, my, 0);
 160         s->mv[0][1][0] = s->mv[0][2][0] = s->mv[0][3][0] = s->mv[0][0][0];
 161         s->mv[0][1][1] = s->mv[0][2][1] = s->mv[0][3][1] = s->mv[0][0][1];
 162         s->mv[1][1][0] = s->mv[1][2][0] = s->mv[1][3][0] = s->mv[1][0][0];
 163         s->mv[1][1][1] = s->mv[1][2][1] = s->mv[1][3][1] = s->mv[1][0][1];
 164         if((s->avctx->workaround_bugs & FF_BUG_DIRECT_BLOCKSIZE) || !s->quarter_sample)
 165             s->mv_type= MV_TYPE_16X16;
 166         else
 167             s->mv_type= MV_TYPE_8X8;
 168         return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1; //Note see prev line
 169     }
 170 }
 171