git.sesse.net Git - ffmpeg/blob - 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 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 "libavutil/thread.h"
  24
  25 #include "mpegutils.h"
  26 #include "mpegvideo.h"
  27 #include "mpeg4video.h"
  28 #include "mpeg4data.h"
  29
  30 static av_cold void mpeg4_init_rl_intra(void)
  31 {
  32     static uint8_t mpeg4_rl_intra_table[2][2 * MAX_RUN + MAX_LEVEL + 3];
  33     ff_rl_init(&ff_mpeg4_rl_intra, mpeg4_rl_intra_table);
  34 }
  35
  36 av_cold void ff_mpeg4_init_rl_intra(void)
  37 {
  38     static AVOnce init_static_once = AV_ONCE_INIT;
  39     ff_thread_once(&init_static_once, mpeg4_init_rl_intra);
  40 }
  41
  42 int ff_mpeg4_get_video_packet_prefix_length(MpegEncContext *s)
  43 {
  44     switch (s->pict_type) {
  45     case AV_PICTURE_TYPE_I:
  46         return 16;
  47     case AV_PICTURE_TYPE_P:
  48     case AV_PICTURE_TYPE_S:
  49         return s->f_code + 15;
  50     case AV_PICTURE_TYPE_B:
  51         return FFMAX3(s->f_code, s->b_code, 2) + 15;
  52     default:
  53         return -1;
  54     }
  55 }
  56
  57 void ff_mpeg4_clean_buffers(MpegEncContext *s)
  58 {
  59     int c_wrap, c_xy, l_wrap, l_xy;
  60
  61     l_wrap = s->b8_stride;
  62     l_xy   = (2 * s->mb_y - 1) * l_wrap + s->mb_x * 2 - 1;
  63     c_wrap = s->mb_stride;
  64     c_xy   = (s->mb_y - 1) * c_wrap + s->mb_x - 1;
  65
  66     /* clean AC */
  67     memset(s->ac_val[0] + l_xy, 0, (l_wrap * 2 + 1) * 16 * sizeof(int16_t));
  68     memset(s->ac_val[1] + c_xy, 0, (c_wrap     + 1) * 16 * sizeof(int16_t));
  69     memset(s->ac_val[2] + c_xy, 0, (c_wrap     + 1) * 16 * sizeof(int16_t));
  70
  71     /* clean MV */
  72     // we can't clear the MVs as they might be needed by a B-frame
  73     s->last_mv[0][0][0] =
  74     s->last_mv[0][0][1] =
  75     s->last_mv[1][0][0] =
  76     s->last_mv[1][0][1] = 0;
  77 }
  78
  79 #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
  80 #define tab_bias (tab_size / 2)
  81
  82 // used by MPEG-4 and rv10 decoder
  83 void ff_mpeg4_init_direct_mv(MpegEncContext *s)
  84 {
  85     int i;
  86     for (i = 0; i < tab_size; i++) {
  87         s->direct_scale_mv[0][i] = (i - tab_bias) * s->pb_time / s->pp_time;
  88         s->direct_scale_mv[1][i] = (i - tab_bias) * (s->pb_time - s->pp_time) /
  89                                    s->pp_time;
  90     }
  91 }
  92
  93 static inline void ff_mpeg4_set_one_direct_mv(MpegEncContext *s, int mx,
  94                                               int my, int i)
  95 {
  96     int xy           = s->block_index[i];
  97     uint16_t time_pp = s->pp_time;
  98     uint16_t time_pb = s->pb_time;
  99     int p_mx, p_my;
 100
 101     p_mx = s->next_picture.motion_val[0][xy][0];
 102     if ((unsigned)(p_mx + tab_bias) < tab_size) {
 103         s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias] + mx;
 104         s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
 105                             : s->direct_scale_mv[1][p_mx + tab_bias];
 106     } else {
 107         s->mv[0][i][0] = p_mx * time_pb / time_pp + mx;
 108         s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
 109                             : p_mx * (time_pb - time_pp) / time_pp;
 110     }
 111     p_my = s->next_picture.motion_val[0][xy][1];
 112     if ((unsigned)(p_my + tab_bias) < tab_size) {
 113         s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias] + my;
 114         s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
 115                             : s->direct_scale_mv[1][p_my + tab_bias];
 116     } else {
 117         s->mv[0][i][1] = p_my * time_pb / time_pp + my;
 118         s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
 119                             : p_my * (time_pb - time_pp) / time_pp;
 120     }
 121 }
 122
 123 #undef tab_size
 124 #undef tab_bias
 125
 126 /**
 127  * @return the mb_type
 128  */
 129 int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my)
 130 {
 131     const int mb_index          = s->mb_x + s->mb_y * s->mb_stride;
 132     const int colocated_mb_type = s->next_picture.mb_type[mb_index];
 133     uint16_t time_pp;
 134     uint16_t time_pb;
 135     int i;
 136
 137     // FIXME avoid divides
 138     // try special case with shifts for 1 and 3 B-frames?
 139
 140     if (IS_8X8(colocated_mb_type)) {
 141         s->mv_type = MV_TYPE_8X8;
 142         for (i = 0; i < 4; i++)
 143             ff_mpeg4_set_one_direct_mv(s, mx, my, i);
 144         return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
 145     } else if (IS_INTERLACED(colocated_mb_type)) {
 146         s->mv_type = MV_TYPE_FIELD;
 147         for (i = 0; i < 2; i++) {
 148             int field_select = s->next_picture.ref_index[0][4 * mb_index + 2 * i];
 149             s->field_select[0][i] = field_select;
 150             s->field_select[1][i] = i;
 151             if (s->top_field_first) {
 152                 time_pp = s->pp_field_time - field_select + i;
 153                 time_pb = s->pb_field_time - field_select + i;
 154             } else {
 155                 time_pp = s->pp_field_time + field_select - i;
 156                 time_pb = s->pb_field_time + field_select - i;
 157             }
 158             s->mv[0][i][0] = s->p_field_mv_table[i][0][mb_index][0] *
 159                              time_pb / time_pp + mx;
 160             s->mv[0][i][1] = s->p_field_mv_table[i][0][mb_index][1] *
 161                              time_pb / time_pp + my;
 162             s->mv[1][i][0] = mx ? s->mv[0][i][0] -
 163                                   s->p_field_mv_table[i][0][mb_index][0]
 164                                 : s->p_field_mv_table[i][0][mb_index][0] *
 165                                   (time_pb - time_pp) / time_pp;
 166             s->mv[1][i][1] = my ? s->mv[0][i][1] -
 167                                   s->p_field_mv_table[i][0][mb_index][1]
 168                                 : s->p_field_mv_table[i][0][mb_index][1] *
 169                                   (time_pb - time_pp) / time_pp;
 170         }
 171         return MB_TYPE_DIRECT2 | MB_TYPE_16x8 |
 172                MB_TYPE_L0L1    | MB_TYPE_INTERLACED;
 173     } else {
 174         ff_mpeg4_set_one_direct_mv(s, mx, my, 0);
 175         s->mv[0][1][0] =
 176         s->mv[0][2][0] =
 177         s->mv[0][3][0] = s->mv[0][0][0];
 178         s->mv[0][1][1] =
 179         s->mv[0][2][1] =
 180         s->mv[0][3][1] = s->mv[0][0][1];
 181         s->mv[1][1][0] =
 182         s->mv[1][2][0] =
 183         s->mv[1][3][0] = s->mv[1][0][0];
 184         s->mv[1][1][1] =
 185         s->mv[1][2][1] =
 186         s->mv[1][3][1] = s->mv[1][0][1];
 187         if ((s->avctx->workaround_bugs & FF_BUG_DIRECT_BLOCKSIZE) ||
 188             !s->quarter_sample)
 189             s->mv_type = MV_TYPE_16X16;
 190         else
 191             s->mv_type = MV_TYPE_8X8;
 192         // Note see prev line
 193         return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1;
 194     }
 195 }