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
30static 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
36av_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
42int 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
57void 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
83void 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
93static 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 */
129int 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}
196