[FFmpeg-devel] [PATCH]lavf/vplayerdec: Stricter probing

[Clément Bœsch]

On Tue, Jul 12, 2016 at 12:37:39PM +0200, Carl Eugen Hoyos wrote:
> Hi!
> 
> A user provided a rawvideo frame that is detected as vplayer without attached 
> patch.
> 

can you show a hex dump of the first few bytes?

> Please comment, Carl Eugen

> From 493f24f3d0ba74353ed7742c34a3727c344535eb Mon Sep 17 00:00:00 2001
> From: Carl Eugen Hoyos <cehoyos at ag.or.at>
> Date: Tue, 12 Jul 2016 12:23:58 +0200
> Subject: [PATCH] lavf/vplayerdec: Stricter probing.
> 
> ---
>  libavformat/vplayerdec.c |   10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/libavformat/vplayerdec.c b/libavformat/vplayerdec.c
> index 897c408..c530a47 100644
> --- a/libavformat/vplayerdec.c
> +++ b/libavformat/vplayerdec.c
> @@ -34,10 +34,16 @@ typedef struct {
>  static int vplayer_probe(AVProbeData *p)
>  {
>      char c;
> +    unsigned hh, mm, ss, ms = 0;

we've had surprises with negative timestamps (which can happen), so i
wouldn't make these unsigned (also, you're using signed format string
code)

>      const unsigned char *ptr = p->buf;
>  
> -    if ((sscanf(ptr, "%*d:%*d:%*d.%*d%c", &c) == 1 ||
> -         sscanf(ptr, "%*d:%*d:%*d%c",     &c) == 1) && strchr(": =", c))
> +    if (   (sscanf(ptr, "%d:%d:%d.%d%c", &hh, &mm, &ss, &ms, &c) == 5 ||
> +            sscanf(ptr, "%d:%d:%d%c",    &hh, &mm, &ss,      &c) == 4)
> +        && strchr(": =", c)
> +        && hh < 1000
> +        && mm < 60
> +        && ss < 60
> +        && ms < 1000)

potentially simpler alternative: if you replace the original formats with
"%*3d:%*2d:%*2d.%*2d%c" and "%*3d:%*2d:%*2d%c", does it work?

otherwise I guess patch is fine

>          return AVPROBE_SCORE_MAX;
>      return 0;

-- 
Clément B.
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