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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 |
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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 |
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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 |
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305 | if (ret < 0) |
84 | ✗ | break; | |
85 | |||
86 | /* keep AV_PICTURE_TYPE_BI internal to VC1 */ | ||
87 |
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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 |
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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 |
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305 | if (vpc->v.rff){ |
97 | // repeat field | ||
98 | ✗ | s->repeat_pict = 2; | |
99 |
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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 |
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305 | if (vpc->v.broadcast && vpc->v.interlace && !vpc->v.psf) |
108 |
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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 |
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971 | : AV_PIX_FMT_NONE; |
116 |
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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 |
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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 |
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9846 | while (i < buf_size) { |
148 | uint8_t b; | ||
149 | 5393 | start_code_found = 0; | |
150 |
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38288 | while (i < buf_size && unesc_index < UNESCAPED_THRESHOLD) { |
151 | 32986 | b = buf[i++]; | |
152 | 32986 | unesc_buffer[unesc_index++] = b; | |
153 |
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32986 | if (search_state <= ONE_ZERO) |
154 |
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32765 | search_state = b ? NO_MATCH : search_state + 1; |
155 |
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221 | else if (search_state == TWO_ZEROS) { |
156 |
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130 | if (b == 1) |
157 | 91 | search_state = ONE; | |
158 |
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39 | else if (b > 1) { |
159 |
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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 |
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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 |
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5393 | if (unesc_index >= UNESCAPED_THRESHOLD && !start_code_found) { |
182 |
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57273 | while (i < buf_size) { |
183 |
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52860 | if (search_state == NO_MATCH) { |
184 | 27593 | i += vpc->v.vc1dsp.startcode_find_candidate(buf + i, buf_size - i); | |
185 |
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27593 | if (i < buf_size) { |
186 | 23222 | search_state = ONE_ZERO; | |
187 | } | ||
188 | 27593 | i++; | |
189 | } else { | ||
190 | 25267 | b = buf[i++]; | |
191 |
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25267 | if (search_state == ONE_ZERO) |
192 |
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23231 | search_state = b ? NO_MATCH : TWO_ZEROS; |
193 |
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2036 | else if (search_state == TWO_ZEROS) { |
194 |
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1170 | if (b >= 1) |
195 |
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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 |
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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 |
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957 | if (!(s->flags & PARSER_FLAG_COMPLETE_FRAMES)) { |
212 |
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957 | if (!pic_found && (b == (VC1_CODE_FRAME & 0xFF) || b == (VC1_CODE_FIELD & 0xFF))) { |
213 | 9 | pic_found = 1; | |
214 | } | ||
215 |
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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 |
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4746 | if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { |
229 | ✗ | next = buf_size; | |
230 | } else { | ||
231 |
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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 |
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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 |