FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/mpeg12.c
Date: 2023-12-04 05:51:44
Exec Total Coverage
Lines: 96 104 92.3%
Functions: 5 5 100.0%
Branches: 27 34 79.4%
Line Branch Exec Source
1 /*
2 * MPEG-1/2 decoder
3 * Copyright (c) 2000, 2001 Fabrice Bellard
4 * Copyright (c) 2002-2004 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 /**
24 * @file
25 * MPEG-1/2 decoder
26 */
27
28 #define UNCHECKED_BITSTREAM_READER 1
29
30 #include "libavutil/attributes.h"
31 #include "libavutil/avassert.h"
32 #include "libavutil/thread.h"
33
34 #include "avcodec.h"
35 #include "mpegvideo.h"
36 #include "mpeg12.h"
37 #include "mpeg12codecs.h"
38 #include "mpeg12data.h"
39 #include "mpeg12dec.h"
40 #include "rl.h"
41 #include "startcode.h"
42
43 static const uint8_t table_mb_ptype[7][2] = {
44 { 3, 5 }, // 0x01 MB_INTRA
45 { 1, 2 }, // 0x02 MB_PAT
46 { 1, 3 }, // 0x08 MB_FOR
47 { 1, 1 }, // 0x0A MB_FOR|MB_PAT
48 { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
49 { 1, 5 }, // 0x12 MB_QUANT|MB_PAT
50 { 2, 5 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
51 };
52
53 static const uint8_t table_mb_btype[11][2] = {
54 { 3, 5 }, // 0x01 MB_INTRA
55 { 2, 3 }, // 0x04 MB_BACK
56 { 3, 3 }, // 0x06 MB_BACK|MB_PAT
57 { 2, 4 }, // 0x08 MB_FOR
58 { 3, 4 }, // 0x0A MB_FOR|MB_PAT
59 { 2, 2 }, // 0x0C MB_FOR|MB_BACK
60 { 3, 2 }, // 0x0E MB_FOR|MB_BACK|MB_PAT
61 { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
62 { 2, 6 }, // 0x16 MB_QUANT|MB_BACK|MB_PAT
63 { 3, 6 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
64 { 2, 5 }, // 0x1E MB_QUANT|MB_FOR|MB_BACK|MB_PAT
65 };
66
67 285 av_cold void ff_init_2d_vlc_rl(const uint16_t table_vlc[][2], RL_VLC_ELEM rl_vlc[],
68 const int8_t table_run[], const uint8_t table_level[],
69 int n, unsigned static_size, int flags)
70 {
71 int i;
72 285 VLCElem table[680] = { 0 };
73 285 VLC vlc = { .table = table, .table_allocated = static_size };
74
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 285 av_assert0(static_size <= FF_ARRAY_ELEMS(table));
75 285 vlc_init(&vlc, TEX_VLC_BITS, n + 2, &table_vlc[0][1], 4, 2, &table_vlc[0][0], 4, 2, VLC_INIT_USE_STATIC | flags);
76
77
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 193197 for (i = 0; i < vlc.table_size; i++) {
78 192912 int code = vlc.table[i].sym;
79 192912 int len = vlc.table[i].len;
80 int level, run;
81
82
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 192912 if (len == 0) { // illegal code
83 5930 run = 65;
84 5930 level = MAX_LEVEL;
85
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 186982 } else if (len<0) { //more bits needed
86 1836 run = 0;
87 1836 level = code;
88 } else {
89
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 185146 if (code == n) { //esc
90 2280 run = 65;
91 2280 level = 0;
92
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 182866 } else if (code == n + 1) { //eob
93 22272 run = 0;
94 22272 level = 127;
95 } else {
96 160594 run = table_run [code] + 1;
97 160594 level = table_level[code];
98 }
99 }
100 192912 rl_vlc[i].len = len;
101 192912 rl_vlc[i].level = level;
102 192912 rl_vlc[i].run = run;
103 }
104 285 }
105
106 420382 void ff_mpeg1_clean_buffers(MpegEncContext *s)
107 {
108 420382 s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
109 420382 s->last_dc[1] = s->last_dc[0];
110 420382 s->last_dc[2] = s->last_dc[0];
111 420382 memset(s->last_mv, 0, sizeof(s->last_mv));
112 420382 }
113
114
115 /******************************************/
116 /* decoding */
117
118 VLCElem ff_mv_vlc[266];
119
120 VLCElem ff_dc_lum_vlc[512];
121 VLCElem ff_dc_chroma_vlc[514];
122
123 VLCElem ff_mbincr_vlc[538];
124 VLCElem ff_mb_ptype_vlc[64];
125 VLCElem ff_mb_btype_vlc[64];
126 VLCElem ff_mb_pat_vlc[512];
127
128 RL_VLC_ELEM ff_mpeg1_rl_vlc[680];
129 RL_VLC_ELEM ff_mpeg2_rl_vlc[674];
130
131 137 static av_cold void mpeg12_init_vlcs(void)
132 {
133 137 VLC_INIT_STATIC_TABLE(ff_dc_lum_vlc, DC_VLC_BITS, 12,
134 ff_mpeg12_vlc_dc_lum_bits, 1, 1,
135 ff_mpeg12_vlc_dc_lum_code, 2, 2, 0);
136 137 VLC_INIT_STATIC_TABLE(ff_dc_chroma_vlc, DC_VLC_BITS, 12,
137 ff_mpeg12_vlc_dc_chroma_bits, 1, 1,
138 ff_mpeg12_vlc_dc_chroma_code, 2, 2, 0);
139 137 VLC_INIT_STATIC_TABLE(ff_mv_vlc, MV_VLC_BITS, 17,
140 &ff_mpeg12_mbMotionVectorTable[0][1], 2, 1,
141 &ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 0);
142 137 VLC_INIT_STATIC_TABLE(ff_mbincr_vlc, MBINCR_VLC_BITS, 36,
143 &ff_mpeg12_mbAddrIncrTable[0][1], 2, 1,
144 &ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 0);
145 137 VLC_INIT_STATIC_TABLE(ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64,
146 &ff_mpeg12_mbPatTable[0][1], 2, 1,
147 &ff_mpeg12_mbPatTable[0][0], 2, 1, 0);
148
149 137 VLC_INIT_STATIC_TABLE(ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7,
150 &table_mb_ptype[0][1], 2, 1,
151 &table_mb_ptype[0][0], 2, 1, 0);
152 137 VLC_INIT_STATIC_TABLE(ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11,
153 &table_mb_btype[0][1], 2, 1,
154 &table_mb_btype[0][0], 2, 1, 0);
155
156 137 ff_init_2d_vlc_rl(ff_mpeg1_vlc_table, ff_mpeg1_rl_vlc, ff_mpeg12_run,
157 ff_mpeg12_level, MPEG12_RL_NB_ELEMS,
158 FF_ARRAY_ELEMS(ff_mpeg1_rl_vlc), 0);
159 137 ff_init_2d_vlc_rl(ff_mpeg2_vlc_table, ff_mpeg2_rl_vlc, ff_mpeg12_run,
160 ff_mpeg12_level, MPEG12_RL_NB_ELEMS,
161 FF_ARRAY_ELEMS(ff_mpeg2_rl_vlc), 0);
162 137 }
163
164 299 av_cold void ff_mpeg12_init_vlcs(void)
165 {
166 static AVOnce init_static_once = AV_ONCE_INIT;
167 299 ff_thread_once(&init_static_once, mpeg12_init_vlcs);
168 299 }
169
170 #define MAX_INDEX (64 - 1)
171
172 176424 int ff_mpeg1_decode_block_intra(GetBitContext *gb,
173 const uint16_t *quant_matrix,
174 const uint8_t *scantable, int last_dc[3],
175 int16_t *block, int index, int qscale)
176 {
177 176424 int dc, diff, i = 0, component;
178
179 /* DC coefficient */
180 176424 component = index <= 3 ? 0 : index - 4 + 1;
181
182 176424 diff = decode_dc(gb, component);
183
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 176424 if (diff >= 0xffff)
184 ✗ return AVERROR_INVALIDDATA;
185
186 176424 dc = last_dc[component];
187 176424 dc += diff;
188 176424 last_dc[component] = dc;
189
190 176424 block[0] = dc * quant_matrix[0];
191
192 {
193 176424 OPEN_READER(re, gb);
194 176424 UPDATE_CACHE(re, gb);
195
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 176424 if (((int32_t)GET_CACHE(re, gb)) <= (int32_t)0xBFFFFFFF)
196 36367 goto end;
197
198 /* now quantify & encode AC coefficients */
199 1334003 while (1) {
200 int level, run, j;
201
202
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 1474060 GET_RL_VLC(level, run, re, gb, ff_mpeg1_rl_vlc,
203 TEX_VLC_BITS, 2, 0);
204
205
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 1474060 if (level != 0) {
206 1468795 i += run;
207
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 1468795 if (i > MAX_INDEX)
208 ✗ break;
209
210 1468795 j = scantable[i];
211 1468795 level = (level * qscale * quant_matrix[j]) >> 4;
212 1468795 level = (level - 1) | 1;
213 1468795 level = (level ^ SHOW_SBITS(re, gb, 1)) -
214 1468795 SHOW_SBITS(re, gb, 1);
215 1468795 SKIP_BITS(re, gb, 1);
216 } else {
217 /* escape */
218 5265 run = SHOW_UBITS(re, gb, 6) + 1;
219 5265 LAST_SKIP_BITS(re, gb, 6);
220 5265 UPDATE_CACHE(re, gb);
221 5265 level = SHOW_SBITS(re, gb, 8);
222 5265 SKIP_BITS(re, gb, 8);
223
224
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 5265 if (level == -128) {
225 ✗ level = SHOW_UBITS(re, gb, 8) - 256;
226 ✗ SKIP_BITS(re, gb, 8);
227
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 5265 } else if (level == 0) {
228 ✗ level = SHOW_UBITS(re, gb, 8);
229 ✗ SKIP_BITS(re, gb, 8);
230 }
231
232 5265 i += run;
233
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 5265 if (i > MAX_INDEX)
234 ✗ break;
235
236 5265 j = scantable[i];
237
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 5265 if (level < 0) {
238 2964 level = -level;
239 2964 level = (level * qscale * quant_matrix[j]) >> 4;
240 2964 level = (level - 1) | 1;
241 2964 level = -level;
242 } else {
243 2301 level = (level * qscale * quant_matrix[j]) >> 4;
244 2301 level = (level - 1) | 1;
245 }
246 }
247
248 1474060 block[j] = level;
249
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 1474060 if (((int32_t)GET_CACHE(re, gb)) <= (int32_t)0xBFFFFFFF)
250 140057 break;
251
252 1334003 UPDATE_CACHE(re, gb);
253 }
254 176424 end:
255 176424 LAST_SKIP_BITS(re, gb, 2);
256 176424 CLOSE_READER(re, gb);
257 }
258
259
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 176424 if (i > MAX_INDEX)
260 ✗ i = AVERROR_INVALIDDATA;
261
262 176424 return i;
263 }
264