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2ba45a60 DM |
1 | /* |
2 | * Copyright (c) 2012 Justin Ruggles | |
3 | * | |
4 | * This file is part of FFmpeg. | |
5 | * | |
6 | * FFmpeg is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2.1 of the License, or (at your option) any later version. | |
10 | * | |
11 | * FFmpeg is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with FFmpeg; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | */ | |
20 | ||
21 | /** | |
22 | * @file | |
23 | * Vorbis audio parser | |
24 | * | |
25 | * Determines the duration for each packet. | |
26 | */ | |
27 | ||
f6fa7814 DM |
28 | #include "libavutil/log.h" |
29 | ||
2ba45a60 DM |
30 | #include "get_bits.h" |
31 | #include "parser.h" | |
32 | #include "xiph.h" | |
f6fa7814 DM |
33 | #include "vorbis_parser_internal.h" |
34 | ||
35 | static const AVClass vorbis_parser_class = { | |
36 | .class_name = "Vorbis parser", | |
37 | .item_name = av_default_item_name, | |
38 | .version = LIBAVUTIL_VERSION_INT, | |
39 | }; | |
2ba45a60 | 40 | |
f6fa7814 | 41 | static int parse_id_header(AVVorbisParseContext *s, |
2ba45a60 DM |
42 | const uint8_t *buf, int buf_size) |
43 | { | |
44 | /* Id header should be 30 bytes */ | |
45 | if (buf_size < 30) { | |
f6fa7814 | 46 | av_log(s, AV_LOG_ERROR, "Id header is too short\n"); |
2ba45a60 DM |
47 | return AVERROR_INVALIDDATA; |
48 | } | |
49 | ||
50 | /* make sure this is the Id header */ | |
51 | if (buf[0] != 1) { | |
f6fa7814 | 52 | av_log(s, AV_LOG_ERROR, "Wrong packet type in Id header\n"); |
2ba45a60 DM |
53 | return AVERROR_INVALIDDATA; |
54 | } | |
55 | ||
56 | /* check for header signature */ | |
57 | if (memcmp(&buf[1], "vorbis", 6)) { | |
f6fa7814 | 58 | av_log(s, AV_LOG_ERROR, "Invalid packet signature in Id header\n"); |
2ba45a60 DM |
59 | return AVERROR_INVALIDDATA; |
60 | } | |
61 | ||
62 | if (!(buf[29] & 0x1)) { | |
f6fa7814 | 63 | av_log(s, AV_LOG_ERROR, "Invalid framing bit in Id header\n"); |
2ba45a60 DM |
64 | return AVERROR_INVALIDDATA; |
65 | } | |
66 | ||
67 | s->blocksize[0] = 1 << (buf[28] & 0xF); | |
68 | s->blocksize[1] = 1 << (buf[28] >> 4); | |
69 | ||
70 | return 0; | |
71 | } | |
72 | ||
f6fa7814 | 73 | static int parse_setup_header(AVVorbisParseContext *s, |
2ba45a60 DM |
74 | const uint8_t *buf, int buf_size) |
75 | { | |
76 | GetBitContext gb, gb0; | |
77 | uint8_t *rev_buf; | |
78 | int i, ret = 0; | |
79 | int got_framing_bit, mode_count, got_mode_header, last_mode_count = 0; | |
80 | ||
81 | /* avoid overread */ | |
82 | if (buf_size < 7) { | |
f6fa7814 | 83 | av_log(s, AV_LOG_ERROR, "Setup header is too short\n"); |
2ba45a60 DM |
84 | return AVERROR_INVALIDDATA; |
85 | } | |
86 | ||
87 | /* make sure this is the Setup header */ | |
88 | if (buf[0] != 5) { | |
f6fa7814 | 89 | av_log(s, AV_LOG_ERROR, "Wrong packet type in Setup header\n"); |
2ba45a60 DM |
90 | return AVERROR_INVALIDDATA; |
91 | } | |
92 | ||
93 | /* check for header signature */ | |
94 | if (memcmp(&buf[1], "vorbis", 6)) { | |
f6fa7814 | 95 | av_log(s, AV_LOG_ERROR, "Invalid packet signature in Setup header\n"); |
2ba45a60 DM |
96 | return AVERROR_INVALIDDATA; |
97 | } | |
98 | ||
99 | /* reverse bytes so we can easily read backwards with get_bits() */ | |
100 | if (!(rev_buf = av_malloc(buf_size))) { | |
f6fa7814 | 101 | av_log(s, AV_LOG_ERROR, "Out of memory\n"); |
2ba45a60 DM |
102 | return AVERROR(ENOMEM); |
103 | } | |
104 | for (i = 0; i < buf_size; i++) | |
105 | rev_buf[i] = buf[buf_size - 1 - i]; | |
106 | init_get_bits(&gb, rev_buf, buf_size * 8); | |
107 | ||
108 | got_framing_bit = 0; | |
109 | while (get_bits_left(&gb) > 97) { | |
110 | if (get_bits1(&gb)) { | |
111 | got_framing_bit = get_bits_count(&gb); | |
112 | break; | |
113 | } | |
114 | } | |
115 | if (!got_framing_bit) { | |
f6fa7814 | 116 | av_log(s, AV_LOG_ERROR, "Invalid Setup header\n"); |
2ba45a60 DM |
117 | ret = AVERROR_INVALIDDATA; |
118 | goto bad_header; | |
119 | } | |
120 | ||
121 | /* Now we search backwards to find possible valid mode counts. This is not | |
122 | * fool-proof because we could have false positive matches and read too | |
123 | * far, but there isn't really any way to be sure without parsing through | |
124 | * all the many variable-sized fields before the modes. This approach seems | |
125 | * to work well in testing, and it is similar to how it is handled in | |
126 | * liboggz. */ | |
127 | mode_count = 0; | |
128 | got_mode_header = 0; | |
129 | while (get_bits_left(&gb) >= 97) { | |
130 | if (get_bits(&gb, 8) > 63 || get_bits(&gb, 16) || get_bits(&gb, 16)) | |
131 | break; | |
132 | skip_bits(&gb, 1); | |
133 | mode_count++; | |
134 | if (mode_count > 64) | |
135 | break; | |
136 | gb0 = gb; | |
137 | if (get_bits(&gb0, 6) + 1 == mode_count) { | |
138 | got_mode_header = 1; | |
139 | last_mode_count = mode_count; | |
140 | } | |
141 | } | |
142 | if (!got_mode_header) { | |
f6fa7814 | 143 | av_log(s, AV_LOG_ERROR, "Invalid Setup header\n"); |
2ba45a60 DM |
144 | ret = AVERROR_INVALIDDATA; |
145 | goto bad_header; | |
146 | } | |
147 | /* All samples I've seen use <= 2 modes, so ask for a sample if we find | |
148 | * more than that, as it is most likely a false positive. If we get any | |
149 | * we may need to approach this the long way and parse the whole Setup | |
150 | * header, but I hope very much that it never comes to that. */ | |
151 | if (last_mode_count > 2) { | |
f6fa7814 | 152 | avpriv_request_sample(s, |
2ba45a60 DM |
153 | "%d modes (either a false positive or a " |
154 | "sample from an unknown encoder)", | |
155 | last_mode_count); | |
156 | } | |
157 | /* We're limiting the mode count to 63 so that we know that the previous | |
158 | * block flag will be in the first packet byte. */ | |
159 | if (last_mode_count > 63) { | |
f6fa7814 | 160 | av_log(s, AV_LOG_ERROR, "Unsupported mode count: %d\n", |
2ba45a60 DM |
161 | last_mode_count); |
162 | ret = AVERROR_INVALIDDATA; | |
163 | goto bad_header; | |
164 | } | |
165 | s->mode_count = mode_count = last_mode_count; | |
166 | /* Determine the number of bits required to code the mode and turn that | |
167 | * into a bitmask to directly access the mode from the first frame byte. */ | |
168 | s->mode_mask = ((1 << (av_log2(mode_count - 1) + 1)) - 1) << 1; | |
169 | /* The previous window flag is the next bit after the mode */ | |
170 | s->prev_mask = (s->mode_mask | 0x1) + 1; | |
171 | ||
172 | init_get_bits(&gb, rev_buf, buf_size * 8); | |
173 | skip_bits_long(&gb, got_framing_bit); | |
174 | for (i = mode_count - 1; i >= 0; i--) { | |
175 | skip_bits_long(&gb, 40); | |
176 | s->mode_blocksize[i] = get_bits1(&gb); | |
177 | } | |
178 | ||
179 | bad_header: | |
180 | av_free(rev_buf); | |
181 | return ret; | |
182 | } | |
183 | ||
f6fa7814 DM |
184 | static int vorbis_parse_init(AVVorbisParseContext *s, |
185 | const uint8_t *extradata, int extradata_size) | |
2ba45a60 DM |
186 | { |
187 | uint8_t *header_start[3]; | |
188 | int header_len[3]; | |
189 | int ret; | |
190 | ||
f6fa7814 | 191 | s->class = &vorbis_parser_class; |
2ba45a60 DM |
192 | s->extradata_parsed = 1; |
193 | ||
f6fa7814 DM |
194 | if ((ret = avpriv_split_xiph_headers(extradata, |
195 | extradata_size, 30, | |
2ba45a60 | 196 | header_start, header_len)) < 0) { |
f6fa7814 | 197 | av_log(s, AV_LOG_ERROR, "Extradata corrupt.\n"); |
2ba45a60 DM |
198 | return ret; |
199 | } | |
200 | ||
f6fa7814 | 201 | if ((ret = parse_id_header(s, header_start[0], header_len[0])) < 0) |
2ba45a60 DM |
202 | return ret; |
203 | ||
f6fa7814 | 204 | if ((ret = parse_setup_header(s, header_start[2], header_len[2])) < 0) |
2ba45a60 DM |
205 | return ret; |
206 | ||
207 | s->valid_extradata = 1; | |
208 | s->previous_blocksize = s->blocksize[s->mode_blocksize[0]]; | |
209 | ||
210 | return 0; | |
211 | } | |
212 | ||
f6fa7814 DM |
213 | int av_vorbis_parse_frame_flags(AVVorbisParseContext *s, const uint8_t *buf, |
214 | int buf_size, int *flags) | |
2ba45a60 DM |
215 | { |
216 | int duration = 0; | |
217 | ||
218 | if (s->valid_extradata && buf_size > 0) { | |
219 | int mode, current_blocksize; | |
220 | int previous_blocksize = s->previous_blocksize; | |
221 | ||
222 | if (buf[0] & 1) { | |
223 | /* If the user doesn't care about special packets, it's a bad one. */ | |
224 | if (!flags) | |
225 | goto bad_packet; | |
226 | ||
227 | /* Set the flag for which kind of special packet it is. */ | |
228 | if (buf[0] == 1) | |
229 | *flags |= VORBIS_FLAG_HEADER; | |
230 | else if (buf[0] == 3) | |
231 | *flags |= VORBIS_FLAG_COMMENT; | |
232 | else | |
233 | goto bad_packet; | |
234 | ||
235 | /* Special packets have no duration. */ | |
236 | return 0; | |
237 | ||
238 | bad_packet: | |
f6fa7814 | 239 | av_log(s, AV_LOG_ERROR, "Invalid packet\n"); |
2ba45a60 DM |
240 | return AVERROR_INVALIDDATA; |
241 | } | |
242 | if (s->mode_count == 1) | |
243 | mode = 0; | |
244 | else | |
245 | mode = (buf[0] & s->mode_mask) >> 1; | |
246 | if (mode >= s->mode_count) { | |
f6fa7814 | 247 | av_log(s, AV_LOG_ERROR, "Invalid mode in packet\n"); |
2ba45a60 DM |
248 | return AVERROR_INVALIDDATA; |
249 | } | |
250 | if(s->mode_blocksize[mode]){ | |
251 | int flag = !!(buf[0] & s->prev_mask); | |
252 | previous_blocksize = s->blocksize[flag]; | |
253 | } | |
254 | current_blocksize = s->blocksize[s->mode_blocksize[mode]]; | |
255 | duration = (previous_blocksize + current_blocksize) >> 2; | |
256 | s->previous_blocksize = current_blocksize; | |
257 | } | |
258 | ||
259 | return duration; | |
260 | } | |
261 | ||
f6fa7814 DM |
262 | int av_vorbis_parse_frame(AVVorbisParseContext *s, const uint8_t *buf, |
263 | int buf_size) | |
2ba45a60 | 264 | { |
f6fa7814 | 265 | return av_vorbis_parse_frame_flags(s, buf, buf_size, NULL); |
2ba45a60 DM |
266 | } |
267 | ||
f6fa7814 | 268 | void av_vorbis_parse_reset(AVVorbisParseContext *s) |
2ba45a60 DM |
269 | { |
270 | if (s->valid_extradata) | |
271 | s->previous_blocksize = s->blocksize[0]; | |
272 | } | |
273 | ||
f6fa7814 DM |
274 | void av_vorbis_parse_free(AVVorbisParseContext **s) |
275 | { | |
276 | av_freep(s); | |
277 | } | |
278 | ||
279 | AVVorbisParseContext *av_vorbis_parse_init(const uint8_t *extradata, | |
280 | int extradata_size) | |
281 | { | |
282 | AVVorbisParseContext *s = av_mallocz(sizeof(*s)); | |
283 | int ret; | |
284 | ||
285 | if (!s) | |
286 | return NULL; | |
287 | ||
288 | ret = vorbis_parse_init(s, extradata, extradata_size); | |
289 | if (ret < 0) { | |
290 | av_vorbis_parse_free(&s); | |
291 | return NULL; | |
292 | } | |
293 | ||
294 | return s; | |
295 | } | |
296 | ||
297 | #if LIBAVCODEC_VERSION_MAJOR < 57 | |
298 | int avpriv_vorbis_parse_extradata(AVCodecContext *avctx, AVVorbisParseContext *s) | |
299 | { | |
300 | return vorbis_parse_init(s, avctx->extradata, avctx->extradata_size); | |
301 | } | |
302 | void avpriv_vorbis_parse_reset(AVVorbisParseContext *s) | |
303 | { | |
304 | av_vorbis_parse_reset(s); | |
305 | } | |
306 | int avpriv_vorbis_parse_frame(AVVorbisParseContext *s, const uint8_t *buf, | |
307 | int buf_size) | |
308 | { | |
309 | return av_vorbis_parse_frame(s, buf, buf_size); | |
310 | } | |
311 | int avpriv_vorbis_parse_frame_flags(AVVorbisParseContext *s, const uint8_t *buf, | |
312 | int buf_size, int *flags) | |
313 | { | |
314 | return av_vorbis_parse_frame_flags(s, buf, buf_size, flags); | |
315 | } | |
316 | #endif | |
317 | ||
2ba45a60 | 318 | #if CONFIG_VORBIS_PARSER |
f6fa7814 DM |
319 | |
320 | typedef struct VorbisParseContext { | |
321 | AVVorbisParseContext *vp; | |
322 | } VorbisParseContext; | |
323 | ||
2ba45a60 DM |
324 | static int vorbis_parse(AVCodecParserContext *s1, AVCodecContext *avctx, |
325 | const uint8_t **poutbuf, int *poutbuf_size, | |
326 | const uint8_t *buf, int buf_size) | |
327 | { | |
328 | VorbisParseContext *s = s1->priv_data; | |
329 | int duration; | |
330 | ||
f6fa7814 DM |
331 | if (!s->vp && avctx->extradata && avctx->extradata_size) { |
332 | s->vp = av_vorbis_parse_init(avctx->extradata, avctx->extradata_size); | |
333 | } | |
334 | if (!s->vp) | |
335 | goto end; | |
2ba45a60 | 336 | |
f6fa7814 | 337 | if ((duration = av_vorbis_parse_frame(s->vp, buf, buf_size)) >= 0) |
2ba45a60 DM |
338 | s1->duration = duration; |
339 | ||
340 | end: | |
341 | /* always return the full packet. this parser isn't doing any splitting or | |
342 | combining, only packet analysis */ | |
343 | *poutbuf = buf; | |
344 | *poutbuf_size = buf_size; | |
345 | return buf_size; | |
346 | } | |
347 | ||
f6fa7814 DM |
348 | static void vorbis_parser_close(AVCodecParserContext *ctx) |
349 | { | |
350 | VorbisParseContext *s = ctx->priv_data; | |
351 | av_vorbis_parse_free(&s->vp); | |
352 | } | |
353 | ||
2ba45a60 DM |
354 | AVCodecParser ff_vorbis_parser = { |
355 | .codec_ids = { AV_CODEC_ID_VORBIS }, | |
356 | .priv_data_size = sizeof(VorbisParseContext), | |
357 | .parser_parse = vorbis_parse, | |
f6fa7814 | 358 | .parser_close = vorbis_parser_close, |
2ba45a60 DM |
359 | }; |
360 | #endif /* CONFIG_VORBIS_PARSER */ |