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avformat/mpjpeg: utilize MIME boundary value to detect start of new frame

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This code is disabled by default so not to regress endpoints sending invalid MIME, but can be enabled via AVOption 'strict_mime_boundary'

Signed-off-by: Alex Agranovsky <alex@sighthound.com>
This commit is contained in:
Alex Agranovsky 2015-11-29 18:54:14 -05:00 committed by wm4
parent 79103f2199
commit 259c71c199
2 changed files with 84 additions and 3 deletions
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15
doc/demuxers.texi
View File

@ -450,6 +450,21 @@ to 1 (-1 means automatic setting, 1 means enabled, 0 means
disabled). Default value is -1.
@end table
@section mpjpeg
MJPEG encapsulated in multi-part MIME demuxer.
This demuxer allows reading of MJPEG, where each frame is represented as a part of
multipart/x-mixed-replace stream.
@table @option
@item strict_mime_boundary
Default implementation applies a relaxed standard to multi-part MIME boundary detection,
to prevent regression with numerous existing endpoints not generating a proper MIME
MJPEG stream. Turning this option on by setting it to 1 will result in a stricter check
of the boundary value.
@end table
@section rawvideo
Raw video demuxer.

72
libavformat/mpjpegdec.c
View File

@ -20,6 +20,7 @@
*/
#include "libavutil/avstring.h"
#include "libavutil/opt.h"
#include "avformat.h"
#include "internal.h"
@ -28,9 +29,11 @@
typedef struct MPJPEGDemuxContext {
const AVClass *class;
char *boundary;
char *searchstr;
int searchstr_len;
int strict_mime_boundary;
} MPJPEGDemuxContext;
@ -242,6 +245,41 @@ static int parse_multipart_header(AVIOContext *pb,
}
static char* mpjpeg_get_boundary(AVIOContext* pb)
{
uint8_t *mime_type = NULL;
uint8_t *start;
uint8_t *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)
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);
res = av_strndup(start, len);
break;
}
}
av_freep(&mime_type);
return res;
}
static int mpjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)
{
int size;
@ -249,8 +287,17 @@ static int mpjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)
MPJPEGDemuxContext *mpjpeg = s->priv_data;
if (mpjpeg->boundary == NULL) {
mpjpeg->boundary = av_strdup("--");
mpjpeg->searchstr = av_strdup("\r\n--");
uint8_t* boundary = NULL;
if (mpjpeg->strict_mime_boundary) {
boundary = mpjpeg_get_boundary(s->pb);
}
if (boundary != NULL) {
mpjpeg->boundary = boundary;
mpjpeg->searchstr = av_asprintf( "\r\n%s\r\n", 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);
@ -309,6 +356,22 @@ static int mpjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)
return ret;
}
#define OFFSET(x) offsetof(MPJPEGDemuxContext, x)
#define DEC AV_OPT_FLAG_DECODING_PARAM
const AVOption mpjpeg_options[] = {
{ "strict_mime_boundary", "require MIME boundaries match", OFFSET(strict_mime_boundary), AV_OPT_TYPE_INT, {.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"),
@ -318,5 +381,8 @@ AVInputFormat ff_mpjpeg_demuxer = {
.read_probe = mpjpeg_read_probe,
.read_header = mpjpeg_read_header,
.read_packet = mpjpeg_read_packet,
.read_close = mpjpeg_read_close
.read_close = mpjpeg_read_close,
.priv_class = &mpjpeg_demuxer_class
};