[FFmpeg-devel] [PATCH] avfilter/vf_setparams: use YUV colorspace negotiation API

[Niklas Haas]

On Sat, 10 Feb 2024 11:56:29 +0100 Niklas Haas <ffmpeg at haasn.xyz> wrote:
> From: Niklas Haas <git at haasn.dev>
> 
> When this filter overrides frame properties, the outgoing frames have
> a different YUV colorspace than the incoming ones. This requires
> signalling the new colorspace on the outlink, and in particular, making
> sure it's *not* set to a common ref with the input - otherwise the point
> of this filter would be destroyed.
> 
> Untouched fields will continue being passed through, so we don't need to
> do anything there.
> ---
>  libavfilter/vf_setparams.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/libavfilter/vf_setparams.c b/libavfilter/vf_setparams.c
> index ae4c937518..a33c35a942 100644
> --- a/libavfilter/vf_setparams.c
> +++ b/libavfilter/vf_setparams.c
> @@ -23,6 +23,7 @@
>  #include "libavutil/pixfmt.h"
>  #include "libavutil/opt.h"
>  #include "avfilter.h"
> +#include "formats.h"
>  #include "internal.h"
>  #include "video.h"
>  
> @@ -120,6 +121,29 @@ static const AVOption setparams_options[] = {
>  
>  AVFILTER_DEFINE_CLASS(setparams);
>  
> +static int query_formats(AVFilterContext *ctx)
> +{
> +    SetParamsContext *s = ctx->priv;
> +    AVFilterLink *outlink = ctx->outputs[0];
> +    int ret;
> +
> +    if (s->colorspace >= 0) {
> +        ret = ff_formats_ref(ff_make_formats_list_singleton(s->colorspace),
> +                             &outlink->incfg.color_spaces);
> +        if (ret < 0)
> +            return ret;
> +    }
> +
> +    if (s->color_range >= 0) {
> +        ret = ff_formats_ref(ff_make_formats_list_singleton(s->color_range),
> +                             &outlink->incfg.color_ranges);
> +        if (ret < 0)
> +            return ret;
> +    }
> +
> +    return 0;
> +}
> +
>  static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
>  {
>      AVFilterContext *ctx = inlink->dst;
> @@ -177,6 +201,7 @@ const AVFilter ff_vf_setparams = {
>      .flags       = AVFILTER_FLAG_METADATA_ONLY,
>      FILTER_INPUTS(inputs),
>      FILTER_OUTPUTS(ff_video_default_filterpad),
> +    FILTER_QUERY_FUNC(query_formats),
>  };
>  
>  #if CONFIG_SETRANGE_FILTER
> @@ -217,6 +242,7 @@ const AVFilter ff_vf_setrange = {
>      .flags       = AVFILTER_FLAG_METADATA_ONLY,
>      FILTER_INPUTS(inputs),
>      FILTER_OUTPUTS(ff_video_default_filterpad),
> +    FILTER_QUERY_FUNC(query_formats),
>  };
>  #endif /* CONFIG_SETRANGE_FILTER */

Will merge rather soon without objection, as this prevents vf_setparams
from working correctly.