[FFmpeg-devel] [PATCH] avfilter/vf_bwdif: consider chroma subsampling when enforcing minimum dimensions

[Cosmin Stejerean]

> On Nov 29, 2023, at 11:36 AM, Dennis Mungai <dmngaie at gmail.com> wrote:
> 
> On Wed, 29 Nov 2023 at 22:26, Cosmin Stejerean via ffmpeg-devel <
> ffmpeg-devel at ffmpeg.org> wrote:
> 
>> 
>> 
>>> On Nov 28, 2023, at 5:30 AM, Thomas Mundt <tmundt75 at gmail.com> wrote:
>>> 
>>> Hi Cosmin,
>>> 
>>> Cosmin Stejerean via ffmpeg-devel <ffmpeg-devel at ffmpeg.org> schrieb am
>> Sa.,
>>> 25. Nov. 2023, 21:39:
>>> 
>>>> Fixes #10688
>>>> 
>>>> Signed-off-by: Cosmin Stejerean <cosmin at cosmin.at>
>>>> ---
>>>> libavfilter/vf_bwdif.c | 12 ++++++++++++
>>>> 1 file changed, 12 insertions(+)
>>>> 
>>>> diff --git a/libavfilter/vf_bwdif.c b/libavfilter/vf_bwdif.c
>>>> index 137cd5ef13..bce11c39f7 100644
>>>> --- a/libavfilter/vf_bwdif.c
>>>> +++ b/libavfilter/vf_bwdif.c
>>>> @@ -197,6 +197,18 @@ static int config_props(AVFilterLink *link)
>>>>    }
>>>> 
>>>>    yadif->csp = av_pix_fmt_desc_get(link->format);
>>>> +
>>>> +    if (yadif->csp->nb_components > 1) {
>>>> +        int w_chroma, h_chroma;
>>>> +        h_chroma = AV_CEIL_RSHIFT(link->h, yadif->csp->log2_chroma_h);
>>>> +        w_chroma = AV_CEIL_RSHIFT(link->w, yadif->csp->log2_chroma_w);
>>>> +
>>>> +        if (w_chroma < 3 || h_chroma < 4) {
>>>> +            av_log(ctx, AV_LOG_ERROR, "Video with planes less than 3
>>>> columns or 4 lines is not supported\n");
>>>> +            return AVERROR(EINVAL);
>>>> +        }
>>>> +    }
>>>> +
>>>> 
>>> 
>>> Thanks for your quick patch.
>>> Could you please make the size check for all components and remove the
>> old
>>> one to avoid having two size checks in a row?
>>> 
>> 
>> Certainly, will send a v2 shortly.
>> 
>> - Cosmin
>> 
>> 
> Does this change also need to be replicated to bwdif_cuda?
> 


Good callout, it's like the that both bwdif_cuda and bwdif_vulkan need similar updates as they both have checks for width and height and would likely encounter the same problem on the chroma planes. I'll include both of those in v2.

On a side note the minimum width and height requirements are a bit different between the three filters in terms of whether 3x4, 3x3 or 4x4 are the minimum required dimensions. I'm assuming this is intentional based on the underlying filters but just wanted to double check whether it might be worth unifying all of these to say min 4x4 for consistency.

- Cosmin