[FFmpeg-devel] [PATCH] palettegen: Fill with last color, not black

[Clément Bœsch]

On Wed, Jan 16, 2019 at 01:40:20PM +0100, Tomas Härdin wrote:
> Hi
> 
> I was helping the fine folks at peppercarrot.com with web video
> nonsense, and I notice palettegen outputs more colors than it should
> due to padding the generated palette with pure black.
> 
> Compare this (ffmpeg version 3.2.12-1~deb9u1):
> http://www.härdin.se/files/peppercarrot_gif/output-blackspecks-64.gif
> with this (282a471 with this patch applied):
> http://www.härdin.se/files/peppercarrot_gif/output-fixed-64.gif
> 
> The attached patch fixes this by padding with the last color instead of
> black.
> 
> /Tomas

> From 3a01f62fdcc95cc7afaf5aa6e439b8742cce43bc Mon Sep 17 00:00:00 2001
> From: =?UTF-8?q?Tomas=20H=C3=A4rdin?= <tjoppen at acc.umu.se>
> Date: Wed, 16 Jan 2019 13:07:48 +0100
> Subject: [PATCH] palettegen: Fill with last color, not black
> 
> If we fill with black then the generated palette will have one color more
> than what the user requested. This also resulted in unwanted black specks in
> the output of paletteuse, especially when generating small palettes.
> ---
>  libavfilter/vf_palettegen.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/libavfilter/vf_palettegen.c b/libavfilter/vf_palettegen.c
> index 5ff73e6b2b..44323782d2 100644
> --- a/libavfilter/vf_palettegen.c
> +++ b/libavfilter/vf_palettegen.c
> @@ -245,7 +245,7 @@ static void write_palette(AVFilterContext *ctx, AVFrame *out)
>                      av_log(ctx, AV_LOG_WARNING, "Dupped color: %08"PRIX32"\n", pal[x]);
>                  last_color = pal[x];
>              } else {
> -                pal[x] = 0xff000000; // pad with black
> +                pal[x] = last_color; // pad with last color
>              }
>          }
>          pal += pal_linesize;

Code LGTM, thanks

No FATE change?

Regards,

-- 
Clément B.
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