[FFmpeg-devel] [PATCH] Allow mpjpeg demuxer to process MIME parts which do not include Content-Length header.

[Alex Agranovsky]

On November 25, 2015 at 10:35:33 AM, Alex Agranovsky (alex at sighthound.com) wrote:

On November 24, 2015 at 6:06:36 PM, Michael Niedermayer (michaelni at gmx.at) wrote:

On Tue, Nov 24, 2015 at 03:01:28PM -0500, Alex Agranovsky wrote: 
[...] 

> From 2c253d7978a6c9c2dc701d393eb5b9d68e831c98 Mon Sep 17 00:00:00 2001 
> From: Alex Agranovsky <alex at sighthound.com> 
> Date: Tue, 24 Nov 2015 00:07:34 -0500 
> Subject: [PATCH 2/2] If available, use the actual boundary in HTTP response's 
> Content-Type header, to separate MIME parts in mpjpeg stream 
> 
> This code is disabled by default so not to break some fragile endpoints sending invalid MIME, but can be enabled via AVOption 'strict_mime_boundary' 
> 
> Signed-off-by: Alex Agranovsky <alex at sighthound.com> 
> --- 
> libavformat/mpjpegdec.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++-- 
> 1 file changed, 72 insertions(+), 3 deletions(-) 
> 
> diff --git a/libavformat/mpjpegdec.c b/libavformat/mpjpegdec.c 
> index b9093ea..b89f128 100644 
> --- a/libavformat/mpjpegdec.c 
> +++ b/libavformat/mpjpegdec.c 
> @@ -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; 
>  
>  
> @@ -245,6 +248,43 @@ 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_strncasecmp(start, "boundary=", 9)) { 
> + start += 9; 
> + 
> + 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; 
> @@ -252,8 +292,18 @@ 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_malloc(4+strlen(boundary)+1); 

> + sprintf( mpjpeg->searchstr, "\r\n%s\r\n", boundary ); 

please use snprintf() 


> + } else { 
> + mpjpeg->boundary = av_strdup("--"); 
> + mpjpeg->searchstr = av_strdup("\r\n--"); 
> + } 
> mpjpeg->searchstr_len = strlen(mpjpeg->searchstr); 
> if (!mpjpeg->boundary || !mpjpeg->searchstr) { 
> av_freep(&mpjpeg->boundary); 
> @@ -315,6 +365,22 @@ 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 ff_mpjpeg_demuxer_class = { 

there should be no ff_ as its static 


> + .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"), 
> @@ -324,5 +390,8 @@ 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 = &ff_mpjpeg_demuxer_class 
> }; 
> + 
> + 
> -- 
> 2.4.9 (Apple Git-60) 
> 

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-- 
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB 

Awnsering whenever a program halts or runs forever is 
On a turing machine, in general impossible (turings halting problem). 
On any real computer, always possible as a real computer has a finite number 
of states N, and will either halt in less than N cycles or never halt. 
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Please find the patches attached. First one is unchanged from the previous submission, second one addresses your comments.



Hi - are there any additional corrections I need to address on this set of patches, or is it good to go at this point?

Thanks,
- Alex