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path: root/libavformat/mpjpegdec.c (plain)
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1/*
2 * Multipart JPEG format
3 * Copyright (c) 2015 Luca Barbato
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/avstring.h"
23#include "libavutil/opt.h"
24
25#include "avformat.h"
26#include "internal.h"
27#include "avio_internal.h"
28
29
30
31typedef struct MPJPEGDemuxContext {
32 const AVClass *class;
33 char *boundary;
34 char *searchstr;
35 int searchstr_len;
36 int strict_mime_boundary;
37} MPJPEGDemuxContext;
38
39
40static void trim_right(char *p)
41{
42 char *end;
43
44 if (!p || !*p)
45 return;
46
47 end = p + strlen(p);
48 while (end > p && av_isspace(*(end-1)))
49 *(--end) = '\0';
50}
51
52static int get_line(AVIOContext *pb, char *line, int line_size)
53{
54 ff_get_line(pb, line, line_size);
55
56 if (pb->error)
57 return pb->error;
58
59 if (pb->eof_reached)
60 return AVERROR_EOF;
61
62 trim_right(line);
63 return 0;
64}
65
66
67
68static int split_tag_value(char **tag, char **value, char *line)
69{
70 char *p = line;
71 int foundData = 0;
72
73 *tag = NULL;
74 *value = NULL;
75
76
77 while (*p != '\0' && *p != ':') {
78 if (!av_isspace(*p)) {
79 foundData = 1;
80 }
81 p++;
82 }
83 if (*p != ':')
84 return foundData ? AVERROR_INVALIDDATA : 0;
85
86 *p = '\0';
87 *tag = line;
88 trim_right(*tag);
89
90 p++;
91
92 while (av_isspace(*p))
93 p++;
94
95 *value = p;
96 trim_right(*value);
97
98 return 0;
99}
100
101static int parse_multipart_header(AVIOContext *pb,
102 int* size,
103 const char* expected_boundary,
104 void *log_ctx);
105
106static int mpjpeg_read_close(AVFormatContext *s)
107{
108 MPJPEGDemuxContext *mpjpeg = s->priv_data;
109 av_freep(&mpjpeg->boundary);
110 av_freep(&mpjpeg->searchstr);
111 return 0;
112}
113
114static int mpjpeg_read_probe(AVProbeData *p)
115{
116 AVIOContext *pb;
117 int ret = 0;
118 int size = 0;
119
120 if (p->buf_size < 2 || p->buf[0] != '-' || p->buf[1] != '-')
121 return 0;
122
123 pb = avio_alloc_context(p->buf, p->buf_size, 0, NULL, NULL, NULL, NULL);
124 if (!pb)
125 return 0;
126
127 ret = (parse_multipart_header(pb, &size, "--", NULL) >= 0) ? AVPROBE_SCORE_MAX : 0;
128
129 av_free(pb);
130
131 return ret;
132}
133
134static int mpjpeg_read_header(AVFormatContext *s)
135{
136 AVStream *st;
137 char boundary[70 + 2 + 1] = {0};
138 int64_t pos = avio_tell(s->pb);
139 int ret;
140
141 do {
142 ret = get_line(s->pb, boundary, sizeof(boundary));
143 if (ret < 0)
144 return ret;
145 } while (!boundary[0]);
146
147 if (strncmp(boundary, "--", 2))
148 return AVERROR_INVALIDDATA;
149
150 st = avformat_new_stream(s, NULL);
151 if (!st)
152 return AVERROR(ENOMEM);
153
154 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
155 st->codecpar->codec_id = AV_CODEC_ID_MJPEG;
156
157 avpriv_set_pts_info(st, 60, 1, 25);
158
159 avio_seek(s->pb, pos, SEEK_SET);
160
161 return 0;
162}
163
164static int parse_content_length(const char *value)
165{
166 long int val = strtol(value, NULL, 10);
167
168 if (val == LONG_MIN || val == LONG_MAX)
169 return AVERROR(errno);
170 if (val > INT_MAX)
171 return AVERROR(ERANGE);
172 return val;
173}
174
175static int parse_multipart_header(AVIOContext *pb,
176 int* size,
177 const char* expected_boundary,
178 void *log_ctx)
179{
180 char line[128];
181 int found_content_type = 0;
182 int ret;
183
184 *size = -1;
185
186 // get the CRLF as empty string
187 ret = get_line(pb, line, sizeof(line));
188 if (ret < 0)
189 return ret;
190
191 /* some implementation do not provide the required
192 * initial CRLF (see rfc1341 7.2.1)
193 */
194 while (!line[0]) {
195 ret = get_line(pb, line, sizeof(line));
196 if (ret < 0)
197 return ret;
198 }
199
200 if (!av_strstart(line, expected_boundary, NULL)) {
201 if (log_ctx)
202 av_log(log_ctx,
203 AV_LOG_ERROR,
204 "Expected boundary '%s' not found, instead found a line of %"SIZE_SPECIFIER" bytes\n",
205 expected_boundary,
206 strlen(line));
207
208 return AVERROR_INVALIDDATA;
209 }
210
211 while (!pb->eof_reached) {
212 char *tag, *value;
213
214 ret = get_line(pb, line, sizeof(line));
215 if (ret < 0) {
216 if (ret == AVERROR_EOF)
217 break;
218 return ret;
219 }
220
221 if (line[0] == '\0')
222 break;
223
224 ret = split_tag_value(&tag, &value, line);
225 if (ret < 0)
226 return ret;
227 if (value==NULL || tag==NULL)
228 break;
229
230 if (!av_strcasecmp(tag, "Content-type")) {
231 if (av_strcasecmp(value, "image/jpeg")) {
232 if (log_ctx)
233 av_log(log_ctx, AV_LOG_ERROR,
234 "Unexpected %s : %s\n",
235 tag, value);
236 return AVERROR_INVALIDDATA;
237 } else
238 found_content_type = 1;
239 } else if (!av_strcasecmp(tag, "Content-Length")) {
240 *size = parse_content_length(value);
241 if ( *size < 0 )
242 if (log_ctx)
243 av_log(log_ctx, AV_LOG_WARNING,
244 "Invalid Content-Length value : %s\n",
245 value);
246 }
247 }
248
249 return found_content_type ? 0 : AVERROR_INVALIDDATA;
250}
251
252
253static char* mpjpeg_get_boundary(AVIOContext* pb)
254{
255 uint8_t *mime_type = NULL;
256 const char *start;
257 const char *end;
258 uint8_t *res = NULL;
259 int len;
260
261 /* get MIME type, and skip to the first parameter */
262 av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type);
263 start = mime_type;
264 while (start != NULL && *start != '\0') {
265 start = strchr(start, ';');
266 if (!start)
267 break;
268
269 start = start+1;
270
271 while (av_isspace(*start))
272 start++;
273
274 if (!av_stristart(start, "boundary=", &start)) {
275 end = strchr(start, ';');
276 if (end)
277 len = end - start - 1;
278 else
279 len = strlen(start);
280
281 /* some endpoints may enclose the boundary
282 in Content-Type in quotes */
283 if ( len>2 && *start == '"' && start[len-1] == '"' ) {
284 start++;
285 len -= 2;
286 }
287 res = av_strndup(start, len);
288 break;
289 }
290 }
291
292 av_freep(&mime_type);
293 return res;
294}
295
296
297static int mpjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)
298{
299 int size;
300 int ret;
301
302 MPJPEGDemuxContext *mpjpeg = s->priv_data;
303 if (mpjpeg->boundary == NULL) {
304 uint8_t* boundary = NULL;
305 if (mpjpeg->strict_mime_boundary) {
306 boundary = mpjpeg_get_boundary(s->pb);
307 }
308 if (boundary != NULL) {
309 mpjpeg->boundary = boundary;
310 mpjpeg->searchstr = av_asprintf( "\r\n%s\r\n", boundary );
311 } else {
312 mpjpeg->boundary = av_strdup("--");
313 mpjpeg->searchstr = av_strdup("\r\n--");
314 }
315 if (!mpjpeg->boundary || !mpjpeg->searchstr) {
316 av_freep(&mpjpeg->boundary);
317 av_freep(&mpjpeg->searchstr);
318 return AVERROR(ENOMEM);
319 }
320 mpjpeg->searchstr_len = strlen(mpjpeg->searchstr);
321 }
322
323 ret = parse_multipart_header(s->pb, &size, mpjpeg->boundary, s);
324
325
326 if (ret < 0)
327 return ret;
328
329 if (size > 0) {
330 /* size has been provided to us in MIME header */
331 ret = av_get_packet(s->pb, pkt, size);
332 } else {
333 /* no size was given -- we read until the next boundary or end-of-file */
334 int remaining = 0, len;
335
336 const int read_chunk = 2048;
337 av_init_packet(pkt);
338 pkt->data = NULL;
339 pkt->size = 0;
340 pkt->pos = avio_tell(s->pb);
341
342 /* we may need to return as much as all we've read back to the buffer */
343 ffio_ensure_seekback(s->pb, read_chunk);
344
345 while ((ret = av_append_packet(s->pb, pkt, read_chunk - remaining)) >= 0) {
346 /* scan the new data */
347 char *start;
348
349 len = ret + remaining;
350 start = pkt->data + pkt->size - len;
351 do {
352 if (!memcmp(start, mpjpeg->searchstr, mpjpeg->searchstr_len)) {
353 // got the boundary! rewind the stream
354 avio_seek(s->pb, -len, SEEK_CUR);
355 pkt->size -= len;
356 return pkt->size;
357 }
358 len--;
359 start++;
360 } while (len >= mpjpeg->searchstr_len);
361 remaining = len;
362 }
363
364 /* error or EOF occurred */
365 if (ret == AVERROR_EOF) {
366 ret = pkt->size > 0 ? pkt->size : AVERROR_EOF;
367 } else {
368 av_packet_unref(pkt);
369 }
370 }
371
372 return ret;
373}
374
375#define OFFSET(x) offsetof(MPJPEGDemuxContext, x)
376
377#define DEC AV_OPT_FLAG_DECODING_PARAM
378const AVOption mpjpeg_options[] = {
379 { "strict_mime_boundary", "require MIME boundaries match", OFFSET(strict_mime_boundary), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, DEC },
380 { NULL }
381};
382
383
384static const AVClass mpjpeg_demuxer_class = {
385 .class_name = "MPJPEG demuxer",
386 .item_name = av_default_item_name,
387 .option = mpjpeg_options,
388 .version = LIBAVUTIL_VERSION_INT,
389};
390
391AVInputFormat ff_mpjpeg_demuxer = {
392 .name = "mpjpeg",
393 .long_name = NULL_IF_CONFIG_SMALL("MIME multipart JPEG"),
394 .mime_type = "multipart/x-mixed-replace",
395 .extensions = "mjpg",
396 .priv_data_size = sizeof(MPJPEGDemuxContext),
397 .read_probe = mpjpeg_read_probe,
398 .read_header = mpjpeg_read_header,
399 .read_packet = mpjpeg_read_packet,
400 .read_close = mpjpeg_read_close,
401 .priv_class = &mpjpeg_demuxer_class,
402 .flags = AVFMT_NOTIMESTAMPS,
403};
404
405
406
generated by cgit at 2024-05-17 05:02:40 (GMT)