[FFmpeg-devel] [PATCH v3 3/5] avfilter/vf_showinfo: display user data unregistered message

[James Almer]

On 12/19/2019 2:09 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 | 33 +++++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
> 
> diff --git a/libavfilter/vf_showinfo.c b/libavfilter/vf_showinfo.c
> index 31f6b32aa4..bb3b37e0c5 100644
> --- a/libavfilter/vf_showinfo.c
> +++ b/libavfilter/vf_showinfo.c
> @@ -169,6 +169,36 @@ static void dump_content_light_metadata(AVFilterContext *ctx, AVFrameSideData *s
>             metadata->MaxCLL, metadata->MaxFALL);
>  }
>  
> +static int string_is_ascii(const uint8_t *str)
> +{
> +    while (*str && *str < 128) str++;

I don't think the buffer is guaranteed to end with \0. You have
sd->size, so you should probably use that, while also ensuring it ends
with a \0 so the av_log below using %s works as intended.

Also < 128 includes DEL. And you're not checking for >= 32.

> +    return !*str;
> +}
> +
> +static void dump_user_data_unregistered_metadata(AVFilterContext *ctx, AVFrameSideData *sd)
> +{
> +    const int uuid_size = 16;
> +    uint8_t *user_data = sd->data;
> +
> +    if (sd->size < uuid_size) {
> +        av_log(ctx, AV_LOG_ERROR, "invalid data(%d < UUID(%d-bytes))", sd->size, uuid_size);
> +        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", user_data[i]);
> +    av_log(ctx, AV_LOG_INFO, "\n");
> +
> +    user_data += uuid_size;
> +    /* Only print the user data details if it's string */
> +    if (string_is_ascii(user_data)) {
> +        av_log(ctx, AV_LOG_INFO, "User Data=");
> +        av_log(ctx, AV_LOG_INFO, "%s", user_data);
> +    }
> +}
> +
>  static void dump_color_property(AVFilterContext *ctx, AVFrame *frame)
>  {
>      const char *color_range_str     = av_color_range_name(frame->color_range);
> @@ -319,6 +349,9 @@ 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);
>