path: root/libavcodec/mpeg4video.c (plain)
blob: 2aaa9f734cdd405ceb59239c74fb9c319d0c76f6

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 "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	}
184