aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/mpjpegdec.c
blob: 5fe00fd162d3fa2f0b4d08672a395ef33d2c01de (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
/*
 * Multipart JPEG format
 * Copyright (c) 2015 Luca Barbato
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libavutil/avstring.h"
#include "libavutil/opt.h"

#include "avformat.h"
#include "internal.h"
#include "avio_internal.h"



typedef struct MPJPEGDemuxContext {
    const AVClass *class;
    char       *boundary;
    char       *searchstr;
    int         searchstr_len;
    int         strict_mime_boundary;
} MPJPEGDemuxContext;


static void trim_right(char *p)
{
    char *end;

    if (!p || !*p)
        return;

    end = p + strlen(p);
    while (end > p && av_isspace(*(end-1)))
        *(--end) = '\0';
}

static int get_line(AVIOContext *pb, char *line, int line_size)
{
    ff_get_line(pb, line, line_size);

    if (pb->error)
        return pb->error;

    if (pb->eof_reached)
        return AVERROR_EOF;

    trim_right(line);
    return 0;
}



static int split_tag_value(char **tag, char **value, char *line)
{
    char *p = line;
    int  foundData = 0;

    *tag = NULL;
    *value = NULL;


    while (*p != '\0' && *p != ':') {
        if (!av_isspace(*p)) {
            foundData = 1;
        }
        p++;
    }
    if (*p != ':')
        return foundData ? AVERROR_INVALIDDATA : 0;

    *p   = '\0';
    *tag = line;
    trim_right(*tag);

    p++;

    while (av_isspace(*p))
        p++;

    *value = p;
    trim_right(*value);

    return 0;
}

static int parse_multipart_header(AVIOContext *pb,
                                    int* size,
                                    const char* expected_boundary,
                                    void *log_ctx);

static int mpjpeg_read_close(AVFormatContext *s)
{
    MPJPEGDemuxContext *mpjpeg = s->priv_data;
    av_freep(&mpjpeg->boundary);
    av_freep(&mpjpeg->searchstr);
    return 0;
}

static int mpjpeg_read_probe(const AVProbeData *p)
{
    AVIOContext pb;
    int ret = 0;
    int size = 0;

    if (p->buf_size < 2 || p->buf[0] != '-' || p->buf[1] != '-')
        return 0;

    ffio_init_context(&pb, p->buf, p->buf_size, 0, NULL, NULL, NULL, NULL);

    ret = (parse_multipart_header(&pb, &size, "--", NULL) >= 0) ? AVPROBE_SCORE_MAX : 0;

    return ret;
}

static int mpjpeg_read_header(AVFormatContext *s)
{
    AVStream *st;
    char boundary[70 + 2 + 1] = {0};
    int64_t pos = avio_tell(s->pb);
    int ret;

    do {
        ret = get_line(s->pb, boundary, sizeof(boundary));
        if (ret < 0)
            return ret;
    } while (!boundary[0]);

    if (strncmp(boundary, "--", 2))
        return AVERROR_INVALIDDATA;

    st = avformat_new_stream(s, NULL);
    if (!st)
        return AVERROR(ENOMEM);

    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
    st->codecpar->codec_id   = AV_CODEC_ID_MJPEG;

    avpriv_set_pts_info(st, 60, 1, 25);

    avio_seek(s->pb, pos, SEEK_SET);

    return 0;
}

static int parse_content_length(const char *value)
{
    long int val = strtol(value, NULL, 10);

    if (val == LONG_MIN || val == LONG_MAX)
        return AVERROR(errno);
    if (val > INT_MAX)
        return AVERROR(ERANGE);
    return val;
}

static int parse_multipart_header(AVIOContext *pb,
                            int* size,
                            const char* expected_boundary,
                            void *log_ctx)
{
    char line[128];
    int found_content_type = 0;
    int ret;

    *size = -1;

    // get the CRLF as empty string
    ret = get_line(pb, line, sizeof(line));
    if (ret < 0)
        return ret;

    /* some implementation do not provide the required
     * initial CRLF (see rfc1341 7.2.1)
     */
    while (!line[0]) {
        ret = get_line(pb, line, sizeof(line));
        if (ret < 0)
            return ret;
    }

    if (!av_strstart(line, expected_boundary, NULL)) {
        if (log_ctx)
        av_log(log_ctx,
            AV_LOG_ERROR,
            "Expected boundary '%s' not found, instead found a line of %"SIZE_SPECIFIER" bytes\n",
            expected_boundary,
            strlen(line));

        return AVERROR_INVALIDDATA;
    }

    while (!pb->eof_reached) {
        char *tag, *value;

        ret = get_line(pb, line, sizeof(line));
        if (ret < 0) {
            if (ret == AVERROR_EOF)
                break;
            return ret;
        }

        if (line[0] == '\0')
            break;

        ret = split_tag_value(&tag, &value, line);
        if (ret < 0)
            return ret;
        if (value==NULL || tag==NULL)
            break;

        if (!av_strcasecmp(tag, "Content-type")) {
            if (av_strcasecmp(value, "image/jpeg")) {
                if (log_ctx)
                av_log(log_ctx, AV_LOG_ERROR,
                           "Unexpected %s : %s\n",
                           tag, value);
                return AVERROR_INVALIDDATA;
            } else
                found_content_type = 1;
        } else if (!av_strcasecmp(tag, "Content-Length")) {
            *size = parse_content_length(value);
            if ( *size < 0 )
                if (log_ctx)
                av_log(log_ctx, AV_LOG_WARNING,
                           "Invalid Content-Length value : %s\n",
                           value);
        }
    }

    return found_content_type ? 0 : AVERROR_INVALIDDATA;
}


static char* mpjpeg_get_boundary(AVIOContext* pb)
{
    uint8_t *mime_type = NULL;
    const char *start;
    const char *end;
    uint8_t *res = NULL;
    int     len;

    /* get MIME type, and skip to the first parameter */
    av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type);
    start = mime_type;
    while (start != NULL && *start != '\0') {
        start = strchr(start, ';');
        if (!start)
            break;

        start = start+1;

        while (av_isspace(*start))
            start++;

        if (av_stristart(start, "boundary=", &start)) {
            end = strchr(start, ';');
            if (end)
                len = end - start - 1;
            else
                len = strlen(start);

            /* some endpoints may enclose the boundary
              in Content-Type in quotes */
            if ( len>2 && *start == '"' && start[len-1] == '"' ) {
                start++;
                len -= 2;
            }
            res = av_strndup(start, len);
            break;
        }
    }

    av_freep(&mime_type);
    return res;
}


static int mpjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    int size;
    int ret;

    MPJPEGDemuxContext *mpjpeg = s->priv_data;
    if (mpjpeg->boundary == NULL) {
        uint8_t* boundary = NULL;
        if (mpjpeg->strict_mime_boundary) {
            boundary = mpjpeg_get_boundary(s->pb);
        }
        if (boundary != NULL) {
            mpjpeg->boundary = av_asprintf("--%s", boundary);
            mpjpeg->searchstr = av_asprintf("\r\n--%s\r\n", boundary);
            av_freep(&boundary);
        } else {
            mpjpeg->boundary = av_strdup("--");
            mpjpeg->searchstr = av_strdup("\r\n--");
        }
        if (!mpjpeg->boundary || !mpjpeg->searchstr) {
            av_freep(&mpjpeg->boundary);
            av_freep(&mpjpeg->searchstr);
            return AVERROR(ENOMEM);
        }
        mpjpeg->searchstr_len = strlen(mpjpeg->searchstr);
    }

    ret = parse_multipart_header(s->pb, &size, mpjpeg->boundary, s);


    if (ret < 0)
        return ret;

    if (size > 0) {
        /* size has been provided to us in MIME header */
        ret = av_get_packet(s->pb, pkt, size);
    } else {
        /* no size was given -- we read until the next boundary or end-of-file */
        int len;

        const int read_chunk = 2048;

        pkt->pos  = avio_tell(s->pb);

        while ((ret = ffio_ensure_seekback(s->pb, read_chunk)) >= 0 && /* we may need to return as much as all we've read back to the buffer */
               (ret = av_append_packet(s->pb, pkt, read_chunk)) >= 0) {
            /* scan the new data */
            char *start;

            len = ret;
            start = pkt->data + pkt->size - len;
            do {
                if (!memcmp(start, mpjpeg->searchstr, mpjpeg->searchstr_len)) {
                    // got the boundary! rewind the stream
                    avio_seek(s->pb, -len, SEEK_CUR);
                    pkt->size -= len;
                    return pkt->size;
                }
                len--;
                start++;
            } while (len >= mpjpeg->searchstr_len);
            avio_seek(s->pb, -len, SEEK_CUR);
            pkt->size -= len;
        }

        /* error or EOF occurred */
        if (ret == AVERROR_EOF) {
            ret = pkt->size > 0 ? pkt->size : AVERROR_EOF;
        }
    }

    return ret;
}

#define OFFSET(x) offsetof(MPJPEGDemuxContext, x)

#define DEC AV_OPT_FLAG_DECODING_PARAM
static const AVOption mpjpeg_options[] = {
    { "strict_mime_boundary",  "require MIME boundaries match", OFFSET(strict_mime_boundary), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, DEC },
    { NULL }
};


static const AVClass mpjpeg_demuxer_class = {
    .class_name     = "MPJPEG demuxer",
    .item_name      = av_default_item_name,
    .option         = mpjpeg_options,
    .version        = LIBAVUTIL_VERSION_INT,
};

AVInputFormat ff_mpjpeg_demuxer = {
    .name              = "mpjpeg",
    .long_name         = NULL_IF_CONFIG_SMALL("MIME multipart JPEG"),
    .mime_type         = "multipart/x-mixed-replace",
    .extensions        = "mjpg",
    .priv_data_size    = sizeof(MPJPEGDemuxContext),
    .read_probe        = mpjpeg_read_probe,
    .read_header       = mpjpeg_read_header,
    .read_packet       = mpjpeg_read_packet,
    .read_close        = mpjpeg_read_close,
    .priv_class        = &mpjpeg_demuxer_class,
    .flags             = AVFMT_NOTIMESTAMPS,
};