[FFmpeg-devel] [PATCH] vf_tile: fix output buffer ownership.

[Stefano Sabatini]

On date Wednesday 2012-08-01 12:32:07 +0200, Nicolas George encoded:
> There is no need to start_frame immediately on the output link
> since the rest is only done with the last frame of the tile.
> link->out_buf is now automatically dereferenced; since we give
> it away it must be cleared.
> 
> Fix an assert failure; found by Clément Bœsch.
> 
> Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
> ---
>  libavfilter/vf_tile.c |   14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> 
> Note: at some point I'll have to implement error checking for the push
> functions.
> 
> 
> diff --git a/libavfilter/vf_tile.c b/libavfilter/vf_tile.c
> index a6c7e7a..52d53eb 100644
> --- a/libavfilter/vf_tile.c
> +++ b/libavfilter/vf_tile.c
> @@ -109,7 +109,7 @@ static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
>      avfilter_copy_buffer_ref_props(outlink->out_buf, picref);
>      outlink->out_buf->video->w = outlink->w;
>      outlink->out_buf->video->h = outlink->h;
> -    return ff_start_frame(outlink, outlink->out_buf);
> +    return 0;
>  }
>  
>  static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
> @@ -129,16 +129,15 @@ static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
>      return 0;
>  }
>  

> -static void draw_blank_frame(AVFilterContext *ctx)
> +static void draw_blank_frame(AVFilterContext *ctx, AVFilterBufferRef *out_buf)
>  {
>      TileContext *tile    = ctx->priv;
>      AVFilterLink *inlink  = ctx->inputs[0];
> -    AVFilterLink *outlink = ctx->outputs[0];
>      unsigned x0 = inlink->w * (tile->current % tile->w);
>      unsigned y0 = inlink->h * (tile->current / tile->w);
>  
>      ff_fill_rectangle(&tile->draw, &tile->blank,
> -                      outlink->out_buf->data, outlink->out_buf->linesize,
> +                      out_buf->data, out_buf->linesize,
>                        x0, y0, inlink->w, inlink->h);
>      tile->current++;
>  }

This seems unrelated, you can still access outlink->out_buf and clear
it just before ff_end_frame() (but I agree, it looks cleaner this
way).

> @@ -146,10 +145,13 @@ static void end_last_frame(AVFilterContext *ctx)
>  {
>      TileContext *tile    = ctx->priv;
>      AVFilterLink *outlink = ctx->outputs[0];
> +    AVFilterBufferRef *out_buf = outlink->out_buf;
>  
> +    outlink->out_buf = NULL;
> +    ff_start_frame(outlink, out_buf);
>      while (tile->current < tile->w * tile->h)
> -        draw_blank_frame(ctx);
> -    ff_draw_slice(outlink, 0, outlink->out_buf->video->h, 1);
> +        draw_blank_frame(ctx, out_buf);
> +    ff_draw_slice(outlink, 0, out_buf->video->h, 1);
>      ff_end_frame(outlink);
>      tile->current = 0;
>  }

Should be good otherwise if tested, eventually split the patch (and:
we may consider the opportunity to add a FATE test for it), thanks.
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