git.sesse.net Git - ffmpeg/blob - 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 FFmpeg.
   7  *
   8  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 #if 0
  55     /* clean DC */
  56     memsetw(s->dc_val[0] + l_xy, 1024, l_wrap * 2 + 1);
  57     memsetw(s->dc_val[1] + c_xy, 1024, c_wrap + 1);
  58     memsetw(s->dc_val[2] + c_xy, 1024, c_wrap + 1);
  59 #endif
  60
  61     /* clean AC */
  62     memset(s->ac_val[0] + l_xy, 0, (l_wrap * 2 + 1) * 16 * sizeof(int16_t));
  63     memset(s->ac_val[1] + c_xy, 0, (c_wrap     + 1) * 16 * sizeof(int16_t));
  64     memset(s->ac_val[2] + c_xy, 0, (c_wrap     + 1) * 16 * sizeof(int16_t));
  65
  66     /* clean MV */
  67     // we can't clear the MVs as they might be needed by a b frame
  68 //    memset(s->motion_val + l_xy, 0, (l_wrap * 2 + 1) * 2 * sizeof(int16_t));
  69 //    memset(s->motion_val, 0, 2 * sizeof(int16_t) * (2 + s->mb_width * 2) *
  70 //           (2 + s->mb_height * 2));
  71     s->last_mv[0][0][0] =
  72     s->last_mv[0][0][1] =
  73     s->last_mv[1][0][0] =
  74     s->last_mv[1][0][1] = 0;
  75 }
  76
  77 #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
  78 #define tab_bias (tab_size / 2)
  79
  80 // used by mpeg4 and rv10 decoder
  81 void ff_mpeg4_init_direct_mv(MpegEncContext *s)
  82 {
  83     int i;
  84     for (i = 0; i < tab_size; i++) {
  85         s->direct_scale_mv[0][i] = (i - tab_bias) * s->pb_time / s->pp_time;
  86         s->direct_scale_mv[1][i] = (i - tab_bias) * (s->pb_time - s->pp_time) /
  87                                    s->pp_time;
  88     }
  89 }
  90
  91 static inline void ff_mpeg4_set_one_direct_mv(MpegEncContext *s, int mx,
  92                                               int my, int i)
  93 {
  94     int xy           = s->block_index[i];
  95     uint16_t time_pp = s->pp_time;
  96     uint16_t time_pb = s->pb_time;
  97     int p_mx, p_my;
  98
  99     p_mx = s->next_picture.motion_val[0][xy][0];
 100     if ((unsigned)(p_mx + tab_bias) < tab_size) {
 101         s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias] + mx;
 102         s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
 103                             : s->direct_scale_mv[1][p_mx + tab_bias];
 104     } else {
 105         s->mv[0][i][0] = p_mx * time_pb / time_pp + mx;
 106         s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
 107                             : p_mx * (time_pb - time_pp) / time_pp;
 108     }
 109     p_my = s->next_picture.motion_val[0][xy][1];
 110     if ((unsigned)(p_my + tab_bias) < tab_size) {
 111         s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias] + my;
 112         s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
 113                             : s->direct_scale_mv[1][p_my + tab_bias];
 114     } else {
 115         s->mv[0][i][1] = p_my * time_pb / time_pp + my;
 116         s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
 117                             : p_my * (time_pb - time_pp) / time_pp;
 118     }
 119 }
 120
 121 #undef tab_size
 122 #undef tab_bias
 123
 124 /**
 125  * @return the mb_type
 126  */
 127 int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my)
 128 {
 129     const int mb_index          = s->mb_x + s->mb_y * s->mb_stride;
 130     const int colocated_mb_type = s->next_picture.mb_type[mb_index];
 131     uint16_t time_pp;
 132     uint16_t time_pb;
 133     int i;
 134
 135     // FIXME avoid divides
 136     // try special case with shifts for 1 and 3 B-frames?
 137
 138     if (IS_8X8(colocated_mb_type)) {
 139         s->mv_type = MV_TYPE_8X8;
 140         for (i = 0; i < 4; i++)
 141             ff_mpeg4_set_one_direct_mv(s, mx, my, i);
 142         return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
 143     } else if (IS_INTERLACED(colocated_mb_type)) {
 144         s->mv_type = MV_TYPE_FIELD;
 145         for (i = 0; i < 2; i++) {
 146             int field_select = s->next_picture.ref_index[0][4 * mb_index + 2 * i];
 147             s->field_select[0][i] = field_select;
 148             s->field_select[1][i] = i;
 149             if (s->top_field_first) {
 150                 time_pp = s->pp_field_time - field_select + i;
 151                 time_pb = s->pb_field_time - field_select + i;
 152             } else {
 153                 time_pp = s->pp_field_time + field_select - i;
 154                 time_pb = s->pb_field_time + field_select - i;
 155             }
 156             s->mv[0][i][0] = s->p_field_mv_table[i][0][mb_index][0] *
 157                              time_pb / time_pp + mx;
 158             s->mv[0][i][1] = s->p_field_mv_table[i][0][mb_index][1] *
 159                              time_pb / time_pp + my;
 160             s->mv[1][i][0] = mx ? s->mv[0][i][0] -
 161                                   s->p_field_mv_table[i][0][mb_index][0]
 162                                 : s->p_field_mv_table[i][0][mb_index][0] *
 163                                   (time_pb - time_pp) / time_pp;
 164             s->mv[1][i][1] = my ? s->mv[0][i][1] -
 165                                   s->p_field_mv_table[i][0][mb_index][1]
 166                                 : s->p_field_mv_table[i][0][mb_index][1] *
 167                                   (time_pb - time_pp) / time_pp;
 168         }
 169         return MB_TYPE_DIRECT2 | MB_TYPE_16x8 |
 170                MB_TYPE_L0L1    | MB_TYPE_INTERLACED;
 171     } else {
 172         ff_mpeg4_set_one_direct_mv(s, mx, my, 0);
 173         s->mv[0][1][0] =
 174         s->mv[0][2][0] =
 175         s->mv[0][3][0] = s->mv[0][0][0];
 176         s->mv[0][1][1] =
 177         s->mv[0][2][1] =
 178         s->mv[0][3][1] = s->mv[0][0][1];
 179         s->mv[1][1][0] =
 180         s->mv[1][2][0] =
 181         s->mv[1][3][0] = s->mv[1][0][0];
 182         s->mv[1][1][1] =
 183         s->mv[1][2][1] =
 184         s->mv[1][3][1] = s->mv[1][0][1];
 185         if ((s->avctx->workaround_bugs & FF_BUG_DIRECT_BLOCKSIZE) ||
 186             !s->quarter_sample)
 187             s->mv_type = MV_TYPE_16X16;
 188         else
 189             s->mv_type = MV_TYPE_8X8;
 190         // Note see prev line
 191         return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1;
 192     }
 193 }