[FFmpeg-devel] [PATCH] vf_overlay: clear cur_buf only in end_frame.

[Michael Niedermayer]

On Thu, Jul 26, 2012 at 07:09:16PM +0200, Nicolas George wrote:
> Fix a segfault when a copy is needed.
> 
> Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
> ---
>  libavfilter/vf_overlay.c |    9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/libavfilter/vf_overlay.c b/libavfilter/vf_overlay.c
> index 05e9e1b..58a059d 100644
> --- a/libavfilter/vf_overlay.c
> +++ b/libavfilter/vf_overlay.c
> @@ -513,11 +513,8 @@ static int start_frame_main(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
>      flush_frames(ctx);
>      inpicref->pts = av_rescale_q(inpicref->pts, ctx->inputs[MAIN]->time_base,
>                                   ctx->outputs[0]->time_base);
> -    if (try_start_frame(ctx, inpicref) < 0) {
> +    if (try_start_frame(ctx, inpicref) < 0)
>          ff_bufqueue_add(ctx, &over->queue_main, inpicref);
> -        av_assert1(inpicref == inlink->cur_buf);
> -        inlink->cur_buf = NULL;
> -    }
>      return 0;
>  }
>  
> @@ -546,8 +543,10 @@ static int end_frame_main(AVFilterLink *inlink)
>      AVFilterBufferRef *outpicref = outlink->out_buf;
>      flush_frames(ctx);
>  
> -    if (!outpicref)
> +    if (!outpicref) {
> +        inlink->cur_buf = NULL;
>          return 0;
> +    }
>      return ff_end_frame(ctx->outputs[0]);

this looks fragile, implicating from the value of out_buf if
cur_buf has been copied
it might make more sense to create a new reference so the original
can saftely be freed or add a seperate flag that indicates if cur_buf
has to be set to NULL before returning

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Complexity theory is the science of finding the exact solution to an
approximation. Benchmarking OTOH is finding an approximation of the exact
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