libavcodec/mpeg4video.c

   1 /*
   2  * MPEG-4 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 "mpegutils.h"
  24 #include "mpegvideo.h"
  25 #include "mpeg4video.h"
  26 #include "mpeg4data.h"
  27
  28 uint8_t ff_mpeg4_static_rl_table_store[3][2][2 * MAX_RUN + MAX_LEVEL + 3];
  29
  30 int ff_mpeg4_get_video_packet_prefix_length(MpegEncContext *s)
  31 {
  32     switch (s->pict_type) {
  33     case AV_PICTURE_TYPE_I:
  34         return 16;
  35     case AV_PICTURE_TYPE_P:
  36     case AV_PICTURE_TYPE_S:
  37         return s->f_code + 15;
  38     case AV_PICTURE_TYPE_B:
  39         return FFMAX3(s->f_code, s->b_code, 2) + 15;
  40     default:
  41         return -1;
  42     }
  43 }
  44
  45 void ff_mpeg4_clean_buffers(MpegEncContext *s)
  46 {
  47     int c_wrap, c_xy, l_wrap, l_xy;
  48
  49     l_wrap = s->b8_stride;
  50     l_xy   = (2 * s->mb_y - 1) * l_wrap + s->mb_x * 2 - 1;
  51     c_wrap = s->mb_stride;
  52     c_xy   = (s->mb_y - 1) * c_wrap + s->mb_x - 1;
  53
  54     /* clean AC */
  55     memset(s->ac_val[0] + l_xy, 0, (l_wrap * 2 + 1) * 16 * sizeof(int16_t));
  56     memset(s->ac_val[1] + c_xy, 0, (c_wrap     + 1) * 16 * sizeof(int16_t));
  57     memset(s->ac_val[2] + c_xy, 0, (c_wrap     + 1) * 16 * sizeof(int16_t));
  58
  59     /* clean MV */
  60     // we can't clear the MVs as they might be needed by a B-frame
  61     s->last_mv[0][0][0] =
  62     s->last_mv[0][0][1] =
  63     s->last_mv[1][0][0] =
  64     s->last_mv[1][0][1] = 0;
  65 }
  66
  67 #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
  68 #define tab_bias (tab_size / 2)
  69
  70 // used by MPEG-4 and rv10 decoder
  71 void ff_mpeg4_init_direct_mv(MpegEncContext *s)
  72 {
  73     int i;
  74     for (i = 0; i < tab_size; i++) {
  75         s->direct_scale_mv[0][i] = (i - tab_bias) * s->pb_time / s->pp_time;
  76         s->direct_scale_mv[1][i] = (i - tab_bias) * (s->pb_time - s->pp_time) /
  77                                    s->pp_time;
  78     }
  79 }
  80
  81 static inline void ff_mpeg4_set_one_direct_mv(MpegEncContext *s, int mx,
  82                                               int my, int i)
  83 {
  84     int xy           = s->block_index[i];
  85     uint16_t time_pp = s->pp_time;
  86     uint16_t time_pb = s->pb_time;
  87     int p_mx, p_my;
  88
  89     p_mx = s->next_picture.motion_val[0][xy][0];
  90     if ((unsigned)(p_mx + tab_bias) < tab_size) {
  91         s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias] + mx;
  92         s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
  93                             : s->direct_scale_mv[1][p_mx + tab_bias];
  94     } else {
  95         s->mv[0][i][0] = p_mx * time_pb / time_pp + mx;
  96         s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
  97                             : p_mx * (time_pb - time_pp) / time_pp;
  98     }
  99     p_my = s->next_picture.motion_val[0][xy][1];
 100     if ((unsigned)(p_my + tab_bias) < tab_size) {
 101         s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias] + my;
 102         s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
 103                             : s->direct_scale_mv[1][p_my + tab_bias];
 104     } else {
 105         s->mv[0][i][1] = p_my * time_pb / time_pp + my;
 106         s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
 107                             : p_my * (time_pb - time_pp) / time_pp;
 108     }
 109 }
 110
 111 #undef tab_size
 112 #undef tab_bias
 113
 114 /**
 115  * @return the mb_type
 116  */
 117 int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my)
 118 {
 119     const int mb_index          = s->mb_x + s->mb_y * s->mb_stride;
 120     const int colocated_mb_type = s->next_picture.mb_type[mb_index];
 121     uint16_t time_pp;
 122     uint16_t time_pb;
 123     int i;
 124
 125     // FIXME avoid divides
 126     // try special case with shifts for 1 and 3 B-frames?
 127
 128     if (IS_8X8(colocated_mb_type)) {
 129         s->mv_type = MV_TYPE_8X8;
 130         for (i = 0; i < 4; i++)
 131             ff_mpeg4_set_one_direct_mv(s, mx, my, i);
 132         return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
 133     } else if (IS_INTERLACED(colocated_mb_type)) {
 134         s->mv_type = MV_TYPE_FIELD;
 135         for (i = 0; i < 2; i++) {
 136             int field_select = s->next_picture.ref_index[0][4 * mb_index + 2 * i];
 137             s->field_select[0][i] = field_select;
 138             s->field_select[1][i] = i;
 139             if (s->top_field_first) {
 140                 time_pp = s->pp_field_time - field_select + i;
 141                 time_pb = s->pb_field_time - field_select + i;
 142             } else {
 143                 time_pp = s->pp_field_time + field_select - i;
 144                 time_pb = s->pb_field_time + field_select - i;
 145             }
 146             s->mv[0][i][0] = s->p_field_mv_table[i][0][mb_index][0] *
 147                              time_pb / time_pp + mx;
 148             s->mv[0][i][1] = s->p_field_mv_table[i][0][mb_index][1] *
 149                              time_pb / time_pp + my;
 150             s->mv[1][i][0] = mx ? s->mv[0][i][0] -
 151                                   s->p_field_mv_table[i][0][mb_index][0]
 152                                 : s->p_field_mv_table[i][0][mb_index][0] *
 153                                   (time_pb - time_pp) / time_pp;
 154             s->mv[1][i][1] = my ? s->mv[0][i][1] -
 155                                   s->p_field_mv_table[i][0][mb_index][1]
 156                                 : s->p_field_mv_table[i][0][mb_index][1] *
 157                                   (time_pb - time_pp) / time_pp;
 158         }
 159         return MB_TYPE_DIRECT2 | MB_TYPE_16x8 |
 160                MB_TYPE_L0L1    | MB_TYPE_INTERLACED;
 161     } else {
 162         ff_mpeg4_set_one_direct_mv(s, mx, my, 0);
 163         s->mv[0][1][0] =
 164         s->mv[0][2][0] =
 165         s->mv[0][3][0] = s->mv[0][0][0];
 166         s->mv[0][1][1] =
 167         s->mv[0][2][1] =
 168         s->mv[0][3][1] = s->mv[0][0][1];
 169         s->mv[1][1][0] =
 170         s->mv[1][2][0] =
 171         s->mv[1][3][0] = s->mv[1][0][0];
 172         s->mv[1][1][1] =
 173         s->mv[1][2][1] =
 174         s->mv[1][3][1] = s->mv[1][0][1];
 175         if ((s->avctx->workaround_bugs & FF_BUG_DIRECT_BLOCKSIZE) ||
 176             !s->quarter_sample)
 177             s->mv_type = MV_TYPE_16X16;
 178         else
 179             s->mv_type = MV_TYPE_8X8;
 180         // Note see prev line
 181         return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1;
 182     }
 183 }