[FFmpeg-devel] [PATCH v1 3/5] avfilter/vf_showinfo: display user data unregistered message

[James Almer]

On 12/17/2019 7:22 AM, lance.lmwang at gmail.com wrote:
> From: Limin Wang <lance.lmwang at gmail.com>
> 
> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> ---
>  libavfilter/vf_showinfo.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/libavfilter/vf_showinfo.c b/libavfilter/vf_showinfo.c
> index 31f6b32aa4..0d227983c2 100644
> --- a/libavfilter/vf_showinfo.c
> +++ b/libavfilter/vf_showinfo.c
> @@ -169,6 +169,23 @@ static void dump_content_light_metadata(AVFilterContext *ctx, AVFrameSideData *s
>             metadata->MaxCLL, metadata->MaxFALL);
>  }
>  
> +static void dump_user_data_unregistered_metadata(AVFilterContext *ctx, AVFrameSideData *sd)
> +{
> +    const int uuid_size = 16;
> +
> +    if (sd->size < uuid_size) {
> +        av_log(ctx, AV_LOG_ERROR, "invalid data");
> +        return;
> +    }
> +
> +    av_log(ctx, AV_LOG_INFO, "User data unregistered:\n");
> +    av_log(ctx, AV_LOG_INFO, "UUID=");
> +    for (int i = 0; i < uuid_size; i++)
> +        av_log(ctx, AV_LOG_INFO, "%x", sd->data[i]);
> +    av_log(ctx, AV_LOG_INFO, "\n");
> +    av_log(ctx, AV_LOG_INFO, "User Data=%s", sd->data + uuid_size);

I recall we used to print any user unregistered data SEI in debug mode
but eventually stopped since it presented a risk. We can't just blindly
print whatever is contained here. It should at least be checked that
it's actually printable characters and not random binary data.

> +}
> +
>  static void dump_color_property(AVFilterContext *ctx, AVFrame *frame)
>  {
>      const char *color_range_str     = av_color_range_name(frame->color_range);
> @@ -319,6 +336,9 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
>              av_log(ctx, AV_LOG_INFO, "GOP timecode - %s", tcbuf);
>              break;
>          }
> +        case AV_FRAME_DATA_USER_DATA_UNREGISTERED:
> +            dump_user_data_unregistered_metadata(ctx, sd);
> +            break;
>          default:
>              av_log(ctx, AV_LOG_WARNING, "unknown side data type %d (%d bytes)",
>                     sd->type, sd->size);
>