FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/mpeg12.c
Date: 2021-09-22 05:58:22
Exec Total Coverage
Lines: 134 143 93.7%
Branches: 69 78 88.5%

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/timecode.h"
33 #include "libavutil/thread.h"
34
35 #include "internal.h"
36 #include "avcodec.h"
37 #include "mpegvideo.h"
38 #include "error_resilience.h"
39 #include "mpeg12.h"
40 #include "mpeg12data.h"
41 #include "mpegvideodata.h"
42 #include "bytestream.h"
43 #include "thread.h"
44
45 static const uint8_t table_mb_ptype[7][2] = {
46 { 3, 5 }, // 0x01 MB_INTRA
47 { 1, 2 }, // 0x02 MB_PAT
48 { 1, 3 }, // 0x08 MB_FOR
49 { 1, 1 }, // 0x0A MB_FOR|MB_PAT
50 { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
51 { 1, 5 }, // 0x12 MB_QUANT|MB_PAT
52 { 2, 5 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
53 };
54
55 static const uint8_t table_mb_btype[11][2] = {
56 { 3, 5 }, // 0x01 MB_INTRA
57 { 2, 3 }, // 0x04 MB_BACK
58 { 3, 3 }, // 0x06 MB_BACK|MB_PAT
59 { 2, 4 }, // 0x08 MB_FOR
60 { 3, 4 }, // 0x0A MB_FOR|MB_PAT
61 { 2, 2 }, // 0x0C MB_FOR|MB_BACK
62 { 3, 2 }, // 0x0E MB_FOR|MB_BACK|MB_PAT
63 { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
64 { 2, 6 }, // 0x16 MB_QUANT|MB_BACK|MB_PAT
65 { 3, 6 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
66 { 2, 5 }, // 0x1E MB_QUANT|MB_FOR|MB_BACK|MB_PAT
67 };
68
69 236 av_cold void ff_init_2d_vlc_rl(RLTable *rl, unsigned static_size, int flags)
70 {
71 int i;
72 236 VLC_TYPE table[680][2] = {{0}};
73 236 VLC vlc = { .table = table, .table_allocated = static_size };
74
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236 av_assert0(static_size <= FF_ARRAY_ELEMS(table));
75 236 init_vlc(&vlc, TEX_VLC_BITS, rl->n + 2, &rl->table_vlc[0][1], 4, 2, &rl->table_vlc[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC | flags);
76
77
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160002 for (i = 0; i < vlc.table_size; i++) {
78 159766 int code = vlc.table[i][0];
79 159766 int len = vlc.table[i][1];
80 int level, run;
81
82
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159766 if (len == 0) { // illegal code
83 4946 run = 65;
84 4946 level = MAX_LEVEL;
85
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154820 } else if (len<0) { //more bits needed
86 1531 run = 0;
87 1531 level = code;
88 } else {
89
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153289 if (code == rl->n) { //esc
90 1888 run = 65;
91 1888 level = 0;
92
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151401 } else if (code == rl->n+1) { //eob
93 18784 run = 0;
94 18784 level = 127;
95 } else {
96 132617 run = rl->table_run [code] + 1;
97 132617 level = rl->table_level[code];
98 }
99 }
100 159766 rl->rl_vlc[0][i].len = len;
101 159766 rl->rl_vlc[0][i].level = level;
102 159766 rl->rl_vlc[0][i].run = run;
103 }
104 236 }
105
106 303 av_cold void ff_mpeg12_common_init(MpegEncContext *s)
107 {
108
109 303 s->y_dc_scale_table =
110 303 s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision];
111
112 303 }
113
114 396638 void ff_mpeg1_clean_buffers(MpegEncContext *s)
115 {
116 396638 s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
117 396638 s->last_dc[1] = s->last_dc[0];
118 396638 s->last_dc[2] = s->last_dc[0];
119 396638 memset(s->last_mv, 0, sizeof(s->last_mv));
120 396638 }
121
122
123 /******************************************/
124 /* decoding */
125
126 VLC ff_mv_vlc;
127
128 VLC ff_dc_lum_vlc;
129 VLC ff_dc_chroma_vlc;
130
131 VLC ff_mbincr_vlc;
132 VLC ff_mb_ptype_vlc;
133 VLC ff_mb_btype_vlc;
134 VLC ff_mb_pat_vlc;
135
136 117 static av_cold void mpeg12_init_vlcs(void)
137 {
138 117 INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12,
139 ff_mpeg12_vlc_dc_lum_bits, 1, 1,
140 ff_mpeg12_vlc_dc_lum_code, 2, 2, 512);
141 117 INIT_VLC_STATIC(&ff_dc_chroma_vlc, DC_VLC_BITS, 12,
142 ff_mpeg12_vlc_dc_chroma_bits, 1, 1,
143 ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514);
144 117 INIT_VLC_STATIC(&ff_mv_vlc, MV_VLC_BITS, 17,
145 &ff_mpeg12_mbMotionVectorTable[0][1], 2, 1,
146 &ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 266);
147 117 INIT_VLC_STATIC(&ff_mbincr_vlc, MBINCR_VLC_BITS, 36,
148 &ff_mpeg12_mbAddrIncrTable[0][1], 2, 1,
149 &ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538);
150 117 INIT_VLC_STATIC(&ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64,
151 &ff_mpeg12_mbPatTable[0][1], 2, 1,
152 &ff_mpeg12_mbPatTable[0][0], 2, 1, 512);
153
154 117 INIT_VLC_STATIC(&ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7,
155 &table_mb_ptype[0][1], 2, 1,
156 &table_mb_ptype[0][0], 2, 1, 64);
157 117 INIT_VLC_STATIC(&ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11,
158 &table_mb_btype[0][1], 2, 1,
159 &table_mb_btype[0][0], 2, 1, 64);
160
161 117 INIT_2D_VLC_RL(ff_rl_mpeg1, 680, 0);
162 117 INIT_2D_VLC_RL(ff_rl_mpeg2, 674, 0);
163 117 }
164
165 268 av_cold void ff_mpeg12_init_vlcs(void)
166 {
167 static AVOnce init_static_once = AV_ONCE_INIT;
168 268 ff_thread_once(&init_static_once, mpeg12_init_vlcs);
169 268 }
170
171 #if FF_API_FLAG_TRUNCATED
172 /**
173 * Find the end of the current frame in the bitstream.
174 * @return the position of the first byte of the next frame, or -1
175 */
176 41773 int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s)
177 {
178 int i;
179 41773 uint32_t state = pc->state;
180
181 /* EOF considered as end of frame */
182
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41773 if (buf_size == 0)
183 304 return 0;
184
185 /*
186 0 frame start -> 1/4
187 1 first_SEQEXT -> 0/2
188 2 first field start -> 3/0
189 3 second_SEQEXT -> 2/0
190 4 searching end
191 */
192
193
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234561 for (i = 0; i < buf_size; i++) {
194 av_assert1(pc->frame_start_found >= 0 && pc->frame_start_found <= 4);
195
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198456 if (pc->frame_start_found & 1) {
196
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19329 if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80)
197 1746 pc->frame_start_found--;
198
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17583 else if (state == EXT_START_CODE + 2) {
199
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5861 if ((buf[i] & 3) == 3)
200 3824 pc->frame_start_found = 0;
201 else
202 2037 pc->frame_start_found = (pc->frame_start_found + 1) & 3;
203 }
204 19329 state++;
205 } else {
206 179127 i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1;
207
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179127 if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) {
208 5791 i++;
209 5791 pc->frame_start_found = 4;
210 }
211
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179127 if (state == SEQ_END_CODE) {
212 8 pc->frame_start_found = 0;
213 8 pc->state=-1;
214 8 return i+1;
215 }
216
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179119 if (pc->frame_start_found == 2 && state == SEQ_START_CODE)
217 pc->frame_start_found = 0;
218
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179119 if (pc->frame_start_found < 4 && state == EXT_START_CODE)
219 7607 pc->frame_start_found++;
220
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179119 if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) {
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111147 if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) {
222 5356 pc->frame_start_found = 0;
223 5356 pc->state = -1;
224 5356 return i - 3;
225 }
226 }
227
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173763 if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) {
228 5779 ff_fetch_timestamp(s, i - 3, 1, i > 3);
229 }
230 }
231 }
232 36105 pc->state = state;
233 36105 return END_NOT_FOUND;
234 }
235 #endif
236
237 #define MAX_INDEX (64 - 1)
238
239 176526 int ff_mpeg1_decode_block_intra(GetBitContext *gb,
240 const uint16_t *quant_matrix,
241 uint8_t *const scantable, int last_dc[3],
242 int16_t *block, int index, int qscale)
243 {
244 176526 int dc, diff, i = 0, component;
245 176526 RLTable *rl = &ff_rl_mpeg1;
246
247 /* DC coefficient */
248 176526 component = index <= 3 ? 0 : index - 4 + 1;
249
250 176526 diff = decode_dc(gb, component);
251
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176526 if (diff >= 0xffff)
252 return AVERROR_INVALIDDATA;
253
254 176526 dc = last_dc[component];
255 176526 dc += diff;
256 176526 last_dc[component] = dc;
257
258 176526 block[0] = dc * quant_matrix[0];
259
260 {
261 176526 OPEN_READER(re, gb);
262 176526 UPDATE_CACHE(re, gb);
263
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176526 if (((int32_t)GET_CACHE(re, gb)) <= (int32_t)0xBFFFFFFF)
264 36372 goto end;
265
266 /* now quantify & encode AC coefficients */
267 1334388 while (1) {
268 int level, run, j;
269
270
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1474542 GET_RL_VLC(level, run, re, gb, rl->rl_vlc[0],
271 TEX_VLC_BITS, 2, 0);
272
273
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1474542 if (level != 0) {
274 1469278 i += run;
275
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1469278 if (i > MAX_INDEX)
276 break;
277
278 1469278 j = scantable[i];
279 1469278 level = (level * qscale * quant_matrix[j]) >> 4;
280 1469278 level = (level - 1) | 1;
281 1469278 level = (level ^ SHOW_SBITS(re, gb, 1)) -
282 1469278 SHOW_SBITS(re, gb, 1);
283 1469278 SKIP_BITS(re, gb, 1);
284 } else {
285 /* escape */
286 5264 run = SHOW_UBITS(re, gb, 6) + 1;
287 5264 LAST_SKIP_BITS(re, gb, 6);
288 5264 UPDATE_CACHE(re, gb);
289 5264 level = SHOW_SBITS(re, gb, 8);
290 5264 SKIP_BITS(re, gb, 8);
291
292
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5264 if (level == -128) {
293 level = SHOW_UBITS(re, gb, 8) - 256;
294 SKIP_BITS(re, gb, 8);
295
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5264 } else if (level == 0) {
296 level = SHOW_UBITS(re, gb, 8);
297 SKIP_BITS(re, gb, 8);
298 }
299
300 5264 i += run;
301
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5264 if (i > MAX_INDEX)
302 break;
303
304 5264 j = scantable[i];
305
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5264 if (level < 0) {
306 2967 level = -level;
307 2967 level = (level * qscale * quant_matrix[j]) >> 4;
308 2967 level = (level - 1) | 1;
309 2967 level = -level;
310 } else {
311 2297 level = (level * qscale * quant_matrix[j]) >> 4;
312 2297 level = (level - 1) | 1;
313 }
314 }
315
316 1474542 block[j] = level;
317
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1474542 if (((int32_t)GET_CACHE(re, gb)) <= (int32_t)0xBFFFFFFF)
318 140154 break;
319
320 1334388 UPDATE_CACHE(re, gb);
321 }
322 176526 end:
323 176526 LAST_SKIP_BITS(re, gb, 2);
324 176526 CLOSE_READER(re, gb);
325 }
326
327
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176526 if (i > MAX_INDEX)
328 i = AVERROR_INVALIDDATA;
329
330 176526 return i;
331 }
332