FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/vc1_parser.c
Date: 2024-04-19 17:50:32
Exec Total Coverage
Lines: 116 128 90.6%
Functions: 3 3 100.0%
Branches: 80 102 78.4%

Line Branch Exec Source
1 /*
2 * VC-1 and WMV3 parser
3 * Copyright (c) 2006-2007 Konstantin Shishkov
4 * Partly based on vc9.c (c) 2005 Anonymous, Alex Beregszaszi, Michael Niedermayer
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 * VC-1 and WMV3 parser
26 */
27
28 #include "libavutil/attributes.h"
29 #include "parser.h"
30 #include "vc1.h"
31 #include "get_bits.h"
32 #include "vc1dsp.h"
33
34 /** The maximum number of bytes of a sequence, entry point or
35 * frame header whose values we pay any attention to */
36 #define UNESCAPED_THRESHOLD 37
37
38 /** The maximum number of bytes of a sequence, entry point or
39 * frame header which must be valid memory (because they are
40 * used to update the bitstream cache in skip_bits() calls)
41 */
42 #define UNESCAPED_LIMIT 144
43
44 typedef enum {
45 NO_MATCH,
46 ONE_ZERO,
47 TWO_ZEROS,
48 ONE
49 } VC1ParseSearchState;
50
51 typedef struct VC1ParseContext {
52 ParseContext pc;
53 VC1Context v;
54 uint8_t prev_start_code;
55 size_t bytes_to_skip;
56 uint8_t unesc_buffer[UNESCAPED_LIMIT];
57 size_t unesc_index;
58 VC1ParseSearchState search_state;
59 } VC1ParseContext;
60
61 971 static void vc1_extract_header(AVCodecParserContext *s, AVCodecContext *avctx,
62 const uint8_t *buf, int buf_size)
63 {
64 /* Parse the header we just finished unescaping */
65 971 VC1ParseContext *vpc = s->priv_data;
66 GetBitContext gb;
67 int ret;
68 971 vpc->v.s.avctx = avctx;
69 971 init_get_bits8(&gb, buf, buf_size);
70
4/4
✓ Branch 0 taken 9 times.
✓ Branch 1 taken 14 times.
✓ Branch 2 taken 305 times.
✓ Branch 3 taken 643 times.
971 switch (vpc->prev_start_code) {
71 9 case VC1_CODE_SEQHDR & 0xFF:
72 9 ff_vc1_decode_sequence_header(avctx, &vpc->v, &gb);
73 9 break;
74 14 case VC1_CODE_ENTRYPOINT & 0xFF:
75 14 ff_vc1_decode_entry_point(avctx, &vpc->v, &gb);
76 14 break;
77 305 case VC1_CODE_FRAME & 0xFF:
78
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 305 times.
305 if(vpc->v.profile < PROFILE_ADVANCED)
79 ret = ff_vc1_parse_frame_header (&vpc->v, &gb);
80 else
81 305 ret = ff_vc1_parse_frame_header_adv(&vpc->v, &gb);
82
83
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 305 times.
305 if (ret < 0)
84 break;
85
86 /* keep AV_PICTURE_TYPE_BI internal to VC1 */
87
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 305 times.
305 if (vpc->v.s.pict_type == AV_PICTURE_TYPE_BI)
88 s->pict_type = AV_PICTURE_TYPE_B;
89 else
90 305 s->pict_type = vpc->v.s.pict_type;
91
92
1/2
✓ Branch 0 taken 305 times.
✗ Branch 1 not taken.
305 if (vpc->v.broadcast){
93 // process pulldown flags
94 305 s->repeat_pict = 1;
95 // Pulldown flags are only valid when 'broadcast' has been set.
96
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 305 times.
305 if (vpc->v.rff){
97 // repeat field
98 s->repeat_pict = 2;
99
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 305 times.
305 }else if (vpc->v.rptfrm){
100 // repeat frames
101 s->repeat_pict = vpc->v.rptfrm * 2 + 1;
102 }
103 }else{
104 s->repeat_pict = 0;
105 }
106
107
4/6
✓ Branch 0 taken 305 times.
✗ Branch 1 not taken.
✓ Branch 2 taken 44 times.
✓ Branch 3 taken 261 times.
✓ Branch 4 taken 44 times.
✗ Branch 5 not taken.
305 if (vpc->v.broadcast && vpc->v.interlace && !vpc->v.psf)
108
1/2
✓ Branch 0 taken 44 times.
✗ Branch 1 not taken.
44 s->field_order = vpc->v.tff ? AV_FIELD_TT : AV_FIELD_BB;
109 else
110 261 s->field_order = AV_FIELD_PROGRESSIVE;
111
112 305 break;
113 }
114 1942 s->format = vpc->v.chromaformat == 1 ? AV_PIX_FMT_YUV420P
115
2/2
✓ Branch 0 taken 963 times.
✓ Branch 1 taken 8 times.
971 : AV_PIX_FMT_NONE;
116
3/4
✓ Branch 0 taken 959 times.
✓ Branch 1 taken 12 times.
✓ Branch 2 taken 959 times.
✗ Branch 3 not taken.
971 if (avctx->width && avctx->height) {
117 959 s->width = avctx->width;
118 959 s->height = avctx->height;
119 959 s->coded_width = FFALIGN(avctx->coded_width, 16);
120 959 s->coded_height = FFALIGN(avctx->coded_height, 16);
121 }
122 971 }
123
124 4746 static int vc1_parse(AVCodecParserContext *s,
125 AVCodecContext *avctx,
126 const uint8_t **poutbuf, int *poutbuf_size,
127 const uint8_t *buf, int buf_size)
128 {
129 /* Here we do the searching for frame boundaries and headers at
130 * the same time. Only a minimal amount at the start of each
131 * header is unescaped. */
132 4746 VC1ParseContext *vpc = s->priv_data;
133 4746 int pic_found = vpc->pc.frame_start_found;
134 4746 uint8_t *unesc_buffer = vpc->unesc_buffer;
135 4746 size_t unesc_index = vpc->unesc_index;
136 4746 VC1ParseSearchState search_state = vpc->search_state;
137 4746 int start_code_found = 0;
138 4746 int next = END_NOT_FOUND;
139 4746 int i = vpc->bytes_to_skip;
140
141
4/4
✓ Branch 0 taken 4734 times.
✓ Branch 1 taken 12 times.
✓ Branch 2 taken 14 times.
✓ Branch 3 taken 4720 times.
4746 if (pic_found && buf_size == 0) {
142 /* EOF considered as end of frame */
143 14 memset(unesc_buffer + unesc_index, 0, UNESCAPED_THRESHOLD - unesc_index);
144 14 vc1_extract_header(s, avctx, unesc_buffer, unesc_index);
145 14 next = 0;
146 }
147
2/2
✓ Branch 0 taken 5393 times.
✓ Branch 1 taken 4453 times.
9846 while (i < buf_size) {
148 uint8_t b;
149 5393 start_code_found = 0;
150
4/4
✓ Branch 0 taken 38265 times.
✓ Branch 1 taken 23 times.
✓ Branch 2 taken 32986 times.
✓ Branch 3 taken 5279 times.
38288 while (i < buf_size && unesc_index < UNESCAPED_THRESHOLD) {
151 32986 b = buf[i++];
152 32986 unesc_buffer[unesc_index++] = b;
153
2/2
✓ Branch 0 taken 32765 times.
✓ Branch 1 taken 221 times.
32986 if (search_state <= ONE_ZERO)
154
2/2
✓ Branch 0 taken 860 times.
✓ Branch 1 taken 31905 times.
32765 search_state = b ? NO_MATCH : search_state + 1;
155
2/2
✓ Branch 0 taken 130 times.
✓ Branch 1 taken 91 times.
221 else if (search_state == TWO_ZEROS) {
156
2/2
✓ Branch 0 taken 91 times.
✓ Branch 1 taken 39 times.
130 if (b == 1)
157 91 search_state = ONE;
158
1/2
✓ Branch 0 taken 39 times.
✗ Branch 1 not taken.
39 else if (b > 1) {
159
2/2
✓ Branch 0 taken 22 times.
✓ Branch 1 taken 17 times.
39 if (b == 3)
160 22 unesc_index--; // swallow emulation prevention byte
161 39 search_state = NO_MATCH;
162 }
163 }
164 else { // search_state == ONE
165 // Header unescaping terminates early due to detection of next start code
166 91 search_state = NO_MATCH;
167 91 start_code_found = 1;
168 91 break;
169 }
170 }
171
1/4
✗ Branch 0 not taken.
✓ Branch 1 taken 5393 times.
✗ Branch 2 not taken.
✗ Branch 3 not taken.
5393 if ((s->flags & PARSER_FLAG_COMPLETE_FRAMES) &&
172 unesc_index >= UNESCAPED_THRESHOLD &&
173 vpc->prev_start_code == (VC1_CODE_FRAME & 0xFF))
174 {
175 // No need to keep scanning the rest of the buffer for
176 // start codes if we know it contains a complete frame and
177 // we've already unescaped all we need of the frame header
178 vc1_extract_header(s, avctx, unesc_buffer, unesc_index);
179 break;
180 }
181
3/4
✓ Branch 0 taken 5279 times.
✓ Branch 1 taken 114 times.
✓ Branch 2 taken 5279 times.
✗ Branch 3 not taken.
5393 if (unesc_index >= UNESCAPED_THRESHOLD && !start_code_found) {
182
2/2
✓ Branch 0 taken 52860 times.
✓ Branch 1 taken 4413 times.
57273 while (i < buf_size) {
183
2/2
✓ Branch 0 taken 27593 times.
✓ Branch 1 taken 25267 times.
52860 if (search_state == NO_MATCH) {
184 27593 i += vpc->v.vc1dsp.startcode_find_candidate(buf + i, buf_size - i);
185
2/2
✓ Branch 0 taken 23222 times.
✓ Branch 1 taken 4371 times.
27593 if (i < buf_size) {
186 23222 search_state = ONE_ZERO;
187 }
188 27593 i++;
189 } else {
190 25267 b = buf[i++];
191
2/2
✓ Branch 0 taken 23231 times.
✓ Branch 1 taken 2036 times.
25267 if (search_state == ONE_ZERO)
192
2/2
✓ Branch 0 taken 22061 times.
✓ Branch 1 taken 1170 times.
23231 search_state = b ? NO_MATCH : TWO_ZEROS;
193
2/2
✓ Branch 0 taken 1170 times.
✓ Branch 1 taken 866 times.
2036 else if (search_state == TWO_ZEROS) {
194
1/2
✓ Branch 0 taken 1170 times.
✗ Branch 1 not taken.
1170 if (b >= 1)
195
2/2
✓ Branch 0 taken 866 times.
✓ Branch 1 taken 304 times.
1170 search_state = b == 1 ? ONE : NO_MATCH;
196 }
197 else { // search_state == ONE
198 866 search_state = NO_MATCH;
199 866 start_code_found = 1;
200 866 break;
201 }
202 }
203 }
204 }
205
2/2
✓ Branch 0 taken 957 times.
✓ Branch 1 taken 4436 times.
5393 if (start_code_found) {
206 957 vc1_extract_header(s, avctx, unesc_buffer, unesc_index);
207
208 957 vpc->prev_start_code = b;
209 957 unesc_index = 0;
210
211
1/2
✓ Branch 0 taken 957 times.
✗ Branch 1 not taken.
957 if (!(s->flags & PARSER_FLAG_COMPLETE_FRAMES)) {
212
5/6
✓ Branch 0 taken 31 times.
✓ Branch 1 taken 926 times.
✓ Branch 2 taken 22 times.
✓ Branch 3 taken 9 times.
✗ Branch 4 not taken.
✓ Branch 5 taken 22 times.
957 if (!pic_found && (b == (VC1_CODE_FRAME & 0xFF) || b == (VC1_CODE_FIELD & 0xFF))) {
213 9 pic_found = 1;
214 }
215
6/6
✓ Branch 0 taken 926 times.
✓ Branch 1 taken 22 times.
✓ Branch 2 taken 890 times.
✓ Branch 3 taken 36 times.
✓ Branch 4 taken 293 times.
✓ Branch 5 taken 597 times.
948 else if (pic_found && b != (VC1_CODE_FIELD & 0xFF) && b != (VC1_CODE_SLICE & 0xFF)) {
216 293 next = i - 4;
217 293 pic_found = b == (VC1_CODE_FRAME & 0xFF);
218 293 break;
219 }
220 }
221 }
222 }
223
224 4746 vpc->pc.frame_start_found = pic_found;
225 4746 vpc->unesc_index = unesc_index;
226 4746 vpc->search_state = search_state;
227
228
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 4746 times.
4746 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
229 next = buf_size;
230 } else {
231
2/2
✓ Branch 1 taken 4437 times.
✓ Branch 2 taken 309 times.
4746 if (ff_combine_frame(&vpc->pc, next, &buf, &buf_size) < 0) {
232 4437 vpc->bytes_to_skip = 0;
233 4437 *poutbuf = NULL;
234 4437 *poutbuf_size = 0;
235 4437 return buf_size;
236 }
237 }
238
239 /* If we return with a valid pointer to a combined frame buffer
240 * then on the next call then we'll have been unhelpfully rewound
241 * by up to 4 bytes (depending upon whether the start code
242 * overlapped the input buffer, and if so by how much). We don't
243 * want this: it will either cause spurious second detections of
244 * the start code we've already seen, or cause extra bytes to be
245 * inserted at the start of the unescaped buffer. */
246 309 vpc->bytes_to_skip = 4;
247
3/4
✓ Branch 0 taken 2 times.
✓ Branch 1 taken 307 times.
✗ Branch 2 not taken.
✓ Branch 3 taken 2 times.
309 if (next < 0 && next != END_NOT_FOUND)
248 vpc->bytes_to_skip += next;
249
250 309 *poutbuf = buf;
251 309 *poutbuf_size = buf_size;
252 309 return next;
253 }
254
255 8 static av_cold int vc1_parse_init(AVCodecParserContext *s)
256 {
257 8 VC1ParseContext *vpc = s->priv_data;
258 8 vpc->v.s.slice_context_count = 1;
259 8 vpc->v.first_pic_header_flag = 1;
260 8 vpc->v.parse_only = 1;
261 8 vpc->prev_start_code = 0;
262 8 vpc->bytes_to_skip = 0;
263 8 vpc->unesc_index = 0;
264 8 vpc->search_state = NO_MATCH;
265 8 ff_vc1dsp_init(&vpc->v.vc1dsp); /* startcode_find_candidate */
266 8 return 0;
267 }
268
269 const AVCodecParser ff_vc1_parser = {
270 .codec_ids = { AV_CODEC_ID_VC1 },
271 .priv_data_size = sizeof(VC1ParseContext),
272 .parser_init = vc1_parse_init,
273 .parser_parse = vc1_parse,
274 .parser_close = ff_parse_close,
275 };
276