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path: root/libavformat/format.c (plain)
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1/*
2 * Format register and lookup
3 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "libavutil/atomic.h"
23#include "libavutil/avstring.h"
24#include "libavutil/bprint.h"
25#include "libavutil/opt.h"
26
27#include "avio_internal.h"
28#include "avformat.h"
29#include "id3v2.h"
30#include "internal.h"
31
32
33/**
34 * @file
35 * Format register and lookup
36 */
37/** head of registered input format linked list */
38static AVInputFormat *first_iformat = NULL;
39/** head of registered output format linked list */
40static AVOutputFormat *first_oformat = NULL;
41
42static AVInputFormat **last_iformat = &first_iformat;
43static AVOutputFormat **last_oformat = &first_oformat;
44
45AVInputFormat *av_iformat_next(const AVInputFormat *f)
46{
47 if (f)
48 return f->next;
49 else
50 return first_iformat;
51}
52
53AVOutputFormat *av_oformat_next(const AVOutputFormat *f)
54{
55 if (f)
56 return f->next;
57 else
58 return first_oformat;
59}
60
61void av_register_input_format(AVInputFormat *format)
62{
63 AVInputFormat **p = last_iformat;
64
65 // Note, format could be added after the first 2 checks but that implies that *p is no longer NULL
66 while(p != &format->next && !format->next && avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
67 p = &(*p)->next;
68
69 if (!format->next)
70 last_iformat = &format->next;
71}
72
73void av_register_output_format(AVOutputFormat *format)
74{
75 AVOutputFormat **p = last_oformat;
76
77 // Note, format could be added after the first 2 checks but that implies that *p is no longer NULL
78 while(p != &format->next && !format->next && avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
79 p = &(*p)->next;
80
81 if (!format->next)
82 last_oformat = &format->next;
83}
84
85int av_match_ext(const char *filename, const char *extensions)
86{
87 const char *ext;
88
89 if (!filename)
90 return 0;
91
92 ext = strrchr(filename, '.');
93 if (ext)
94 return av_match_name(ext + 1, extensions);
95 return 0;
96}
97
98AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
99 const char *mime_type)
100{
101 AVOutputFormat *fmt = NULL, *fmt_found;
102 int score_max, score;
103
104 /* specific test for image sequences */
105#if CONFIG_IMAGE2_MUXER
106 if (!short_name && filename &&
107 av_filename_number_test(filename) &&
108 ff_guess_image2_codec(filename) != AV_CODEC_ID_NONE) {
109 return av_guess_format("image2", NULL, NULL);
110 }
111#endif
112 /* Find the proper file type. */
113 fmt_found = NULL;
114 score_max = 0;
115 while ((fmt = av_oformat_next(fmt))) {
116 score = 0;
117 if (fmt->name && short_name && av_match_name(short_name, fmt->name))
118 score += 100;
119 if (fmt->mime_type && mime_type && !strcmp(fmt->mime_type, mime_type))
120 score += 10;
121 if (filename && fmt->extensions &&
122 av_match_ext(filename, fmt->extensions)) {
123 score += 5;
124 }
125 if (score > score_max) {
126 score_max = score;
127 fmt_found = fmt;
128 }
129 }
130 return fmt_found;
131}
132
133enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
134 const char *filename, const char *mime_type,
135 enum AVMediaType type)
136{
137 if (av_match_name("segment", fmt->name) || av_match_name("ssegment", fmt->name)) {
138 AVOutputFormat *fmt2 = av_guess_format(NULL, filename, NULL);
139 if (fmt2)
140 fmt = fmt2;
141 }
142
143 if (type == AVMEDIA_TYPE_VIDEO) {
144 enum AVCodecID codec_id = AV_CODEC_ID_NONE;
145
146#if CONFIG_IMAGE2_MUXER
147 if (!strcmp(fmt->name, "image2") || !strcmp(fmt->name, "image2pipe")) {
148 codec_id = ff_guess_image2_codec(filename);
149 }
150#endif
151 if (codec_id == AV_CODEC_ID_NONE)
152 codec_id = fmt->video_codec;
153 return codec_id;
154 } else if (type == AVMEDIA_TYPE_AUDIO)
155 return fmt->audio_codec;
156 else if (type == AVMEDIA_TYPE_SUBTITLE)
157 return fmt->subtitle_codec;
158 else if (type == AVMEDIA_TYPE_DATA)
159 return fmt->data_codec;
160 else
161 return AV_CODEC_ID_NONE;
162}
163
164AVInputFormat *av_find_input_format(const char *short_name)
165{
166 AVInputFormat *fmt = NULL;
167 while ((fmt = av_iformat_next(fmt)))
168 if (av_match_name(short_name, fmt->name))
169 return fmt;
170 return NULL;
171}
172
173AVInputFormat *av_probe_input_format3(AVProbeData *pd, int is_opened,
174 int *score_ret)
175{
176 AVProbeData lpd = *pd;
177 AVInputFormat *fmt1 = NULL, *fmt;
178 int score, score_max = 0;
179 const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];
180 enum nodat {
181 NO_ID3,
182 ID3_ALMOST_GREATER_PROBE,
183 ID3_GREATER_PROBE,
184 ID3_GREATER_MAX_PROBE,
185 } nodat = NO_ID3;
186
187 if (!lpd.buf)
188 lpd.buf = (unsigned char *) zerobuffer;
189
190 if (lpd.buf_size > 10 && ff_id3v2_match(lpd.buf, ID3v2_DEFAULT_MAGIC)) {
191 int id3len = ff_id3v2_tag_len(lpd.buf);
192 if (lpd.buf_size > id3len + 16) {
193 if (lpd.buf_size < 2LL*id3len + 16)
194 nodat = ID3_ALMOST_GREATER_PROBE;
195 lpd.buf += id3len;
196 lpd.buf_size -= id3len;
197 } else if (id3len >= PROBE_BUF_MAX) {
198 nodat = ID3_GREATER_MAX_PROBE;
199 } else
200 nodat = ID3_GREATER_PROBE;
201 }
202
203 fmt = NULL;
204 while ((fmt1 = av_iformat_next(fmt1))) {
205 if (!is_opened == !(fmt1->flags & AVFMT_NOFILE) && strcmp(fmt1->name, "image2"))
206 continue;
207 score = 0;
208 if (fmt1->read_probe) {
209 score = fmt1->read_probe(&lpd);
210 if (score)
211 av_log(NULL, AV_LOG_TRACE, "Probing %s score:%d size:%d\n", fmt1->name, score, lpd.buf_size);
212 if (fmt1->extensions && av_match_ext(lpd.filename, fmt1->extensions)) {
213 switch (nodat) {
214 case NO_ID3:
215 score = FFMAX(score, 1);
216 break;
217 case ID3_GREATER_PROBE:
218 case ID3_ALMOST_GREATER_PROBE:
219 score = FFMAX(score, AVPROBE_SCORE_EXTENSION / 2 - 1);
220 break;
221 case ID3_GREATER_MAX_PROBE:
222 score = FFMAX(score, AVPROBE_SCORE_EXTENSION);
223 break;
224 }
225 }
226 } else if (fmt1->extensions) {
227 if (av_match_ext(lpd.filename, fmt1->extensions))
228 score = AVPROBE_SCORE_EXTENSION;
229 }
230 if (av_match_name(lpd.mime_type, fmt1->mime_type)) {
231 if (AVPROBE_SCORE_MIME > score) {
232 av_log(NULL, AV_LOG_DEBUG, "Probing %s score:%d increased to %d due to MIME type\n", fmt1->name, score, AVPROBE_SCORE_MIME);
233 score = AVPROBE_SCORE_MIME;
234 }
235 }
236 if (score > score_max) {
237 score_max = score;
238 fmt = fmt1;
239 } else if (score == score_max)
240 fmt = NULL;
241 }
242 if (nodat == ID3_GREATER_PROBE)
243 score_max = FFMIN(AVPROBE_SCORE_EXTENSION / 2 - 1, score_max);
244 *score_ret = score_max;
245
246 return fmt;
247}
248
249AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
250{
251 int score_ret;
252 AVInputFormat *fmt = av_probe_input_format3(pd, is_opened, &score_ret);
253 if (score_ret > *score_max) {
254 *score_max = score_ret;
255 return fmt;
256 } else
257 return NULL;
258}
259
260AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened)
261{
262 int score = 0;
263 return av_probe_input_format2(pd, is_opened, &score);
264}
265
266int av_probe_input_buffer2(AVIOContext *pb, AVInputFormat **fmt,
267 const char *filename, void *logctx,
268 unsigned int offset, unsigned int max_probe_size)
269{
270 AVProbeData pd = { filename ? filename : "" };
271 uint8_t *buf = NULL;
272 int ret = 0, probe_size, buf_offset = 0;
273 int score = 0;
274 int ret2;
275
276 if (!max_probe_size)
277 max_probe_size = PROBE_BUF_MAX;
278 else if (max_probe_size < PROBE_BUF_MIN) {
279 av_log(logctx, AV_LOG_ERROR,
280 "Specified probe size value %u cannot be < %u\n", max_probe_size, PROBE_BUF_MIN);
281 return AVERROR(EINVAL);
282 }
283
284 if (offset >= max_probe_size)
285 return AVERROR(EINVAL);
286
287 if (pb->av_class) {
288 uint8_t *mime_type_opt = NULL;
289 char *semi;
290 av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type_opt);
291 pd.mime_type = (const char *)mime_type_opt;
292 semi = pd.mime_type ? strchr(pd.mime_type, ';') : NULL;
293 if (semi) {
294 *semi = '\0';
295 }
296 }
297#if 0
298 if (!*fmt && pb->av_class && av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type) >= 0 && mime_type) {
299 if (!av_strcasecmp(mime_type, "audio/aacp")) {
300 *fmt = av_find_input_format("aac");
301 }
302 av_freep(&mime_type);
303 }
304#endif
305
306 for (probe_size = PROBE_BUF_MIN; probe_size <= max_probe_size && !*fmt;
307 probe_size = FFMIN(probe_size << 1,
308 FFMAX(max_probe_size, probe_size + 1))) {
309 score = probe_size < max_probe_size ? AVPROBE_SCORE_RETRY : 0;
310
311 /* Read probe data. */
312 if ((ret = av_reallocp(&buf, probe_size + AVPROBE_PADDING_SIZE)) < 0)
313 goto fail;
314 if ((ret = avio_read(pb, buf + buf_offset,
315 probe_size - buf_offset)) < 0) {
316 /* Fail if error was not end of file, otherwise, lower score. */
317 if (ret != AVERROR_EOF)
318 goto fail;
319
320 score = 0;
321 ret = 0; /* error was end of file, nothing read */
322 }
323 buf_offset += ret;
324 if (buf_offset < offset)
325 continue;
326 pd.buf_size = buf_offset - offset;
327 pd.buf = &buf[offset];
328
329 memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);
330
331 /* Guess file format. */
332 *fmt = av_probe_input_format2(&pd, 1, &score);
333 if (*fmt) {
334 /* This can only be true in the last iteration. */
335 if (score <= AVPROBE_SCORE_RETRY) {
336 av_log(logctx, AV_LOG_WARNING,
337 "Format %s detected only with low score of %d, "
338 "misdetection possible!\n", (*fmt)->name, score);
339 } else
340 av_log(logctx, AV_LOG_DEBUG,
341 "Format %s probed with size=%d and score=%d\n",
342 (*fmt)->name, probe_size, score);
343#if 0
344 FILE *f = fopen("probestat.tmp", "ab");
345 fprintf(f, "probe_size:%d format:%s score:%d filename:%s\n", probe_size, (*fmt)->name, score, filename);
346 fclose(f);
347#endif
348 }
349 }
350
351 if (!*fmt)
352 ret = AVERROR_INVALIDDATA;
353
354fail:
355 /* Rewind. Reuse probe buffer to avoid seeking. */
356 ret2 = ffio_rewind_with_probe_data(pb, &buf, buf_offset);
357 if (ret >= 0)
358 ret = ret2;
359
360 av_freep(&pd.mime_type);
361 return ret < 0 ? ret : score;
362}
363
364int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
365 const char *filename, void *logctx,
366 unsigned int offset, unsigned int max_probe_size)
367{
368 int ret = av_probe_input_buffer2(pb, fmt, filename, logctx, offset, max_probe_size);
369 return ret < 0 ? ret : 0;
370}
371
generated by cgit at 2024-05-17 02:27:57 (GMT)