Re: [FFmpeg-devel] [PATCH] lavc/vvc: Fix condition for using default scaling factor

From: Nuo Mi <nuomi2021-at-gmail.com@ffmpeg.org>
To: Frank Plowman <post@frankplowman.com>
Cc: Michael Niedermayer <micheal@niedermayer.cc>, ffmpeg-devel@ffmpeg.org
Subject: Re: [FFmpeg-devel] [PATCH] lavc/vvc: Fix condition for using default scaling factor
Date: Sun, 22 Jun 2025 09:27:50 +0800
Message-ID: <CAFXK13c6VSqDm6DSz1N1tmpjE97O6dtJhhS2M9hWqGwkRiBfZw@mail.gmail.com> (raw)
In-Reply-To: <20250621122015.80590-1-post@frankplowman.com>

On Sat, Jun 21, 2025 at 8:20 PM Frank Plowman <post@frankplowman.com> wrote:

> Add handling here for
> sps_scaling_matrix_for_alternative_colour_space_disabled_flag.
>
> Also add parentheses to make behaviour a little more explicit,
> where &&'s precedence over || was used implicitly previously.
>
> Reported-by: Michael Niedermayer <micheal@niedermayer.cc>
> Signed-off-by: Frank Plowman <post@frankplowman.com>
> ---
>  libavcodec/vvc/intra.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/libavcodec/vvc/intra.c b/libavcodec/vvc/intra.c
> index f56b43be66..45fafdb117 100644
> --- a/libavcodec/vvc/intra.c
> +++ b/libavcodec/vvc/intra.c
> @@ -367,10 +367,10 @@ static const uint8_t* derive_scale_m(const
> VVCLocalContext *lc, const TransformB
>      const int log2_matrix_size = (id < 2) ? 1 : (id < 8) ? 2 : 3;
>      uint8_t *p = scale_m;
>
> -
> av_assert0(!sps->r->sps_scaling_matrix_for_alternative_colour_space_disabled_flag);
> -
>      if (!rsh->sh_explicit_scaling_list_used_flag || tb->ts ||
> -        sps->r->sps_scaling_matrix_for_lfnst_disabled_flag &&
> cu->apply_lfnst_flag[tb->c_idx])
> +        (sps->r->sps_scaling_matrix_for_lfnst_disabled_flag &&
> cu->apply_lfnst_flag[tb->c_idx]) ||
> +
> (sps->r->sps_scaling_matrix_for_alternative_colour_space_disabled_flag &&
> +            sps->r->sps_scaling_matrix_designated_colour_space_flag ==
> cu->act_enabled_flag))
>          return ff_vvc_default_scale_m;
>
LGTM.
Thanks.

>
>      if (!sl) {
> --
> 2.47.0
>
>
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