avfilter/vf_colorspace: use colorspace negotiation API

Fixes a regression due to the fact that the colorspace filter does
not use the new API introduced by 8c7934f7.
The scale filter uses it since 45e09a30, and the setparams
filter since 3bf80df3.

Example:
ffprobe -f lavfi yuvtestsrc,setparams=color_primaries=bt470bg:color_trc=
bt470bg:colorspace=bt470bg,colorspace=bt709:range=tv,scale,showinfo

Before:
  color_range:unknown color_space:bt470bg ...
After:
  color_range:tv color_space:bt709 ...
Signed-off-by: Nicolas Gaullier <nicolas.gaullier@cji.paris>
Signed-off-by: Niklas Haas <git@haasn.dev>

libavfilter/vf_colorspace.c

@@ -433,8 +433,7 @@ static int create_filtergraph(AVFilterContext *ctx,
     if (out->color_trc       != s->out_trc) s->out_txchr     = NULL;
     if (in->colorspace       != s->in_csp ||
         in->color_range      != s->in_rng)  s->in_lumacoef   = NULL;
-    if (out->colorspace      != s->out_csp ||
-        out->color_range     != s->out_rng) s->out_lumacoef  = NULL;
+    if (out->color_range     != s->out_rng) s->rgb2yuv       = NULL;
 
     if (!s->out_primaries || !s->in_primaries) {
         s->in_prm = in->color_primaries;
@@ -563,26 +562,8 @@ static int create_filtergraph(AVFilterContext *ctx,
         redo_yuv2rgb = 1;
     }
 
-    if (!s->out_lumacoef) {
-        s->out_csp = out->colorspace;
+    if (!s->rgb2yuv) {
         s->out_rng = out->color_range;
-        s->out_lumacoef = av_csp_luma_coeffs_from_avcsp(s->out_csp);
-        if (!s->out_lumacoef) {
-            if (s->out_csp == AVCOL_SPC_UNSPECIFIED) {
-                if (s->user_all == CS_UNSPECIFIED) {
-                    av_log(ctx, AV_LOG_ERROR,
-                           "Please specify output colorspace\n");
-                } else {
-                    av_log(ctx, AV_LOG_ERROR,
-                           "Unsupported output color property %d\n", s->user_all);
-                }
-            } else {
-                av_log(ctx, AV_LOG_ERROR,
-                       "Unsupported output colorspace %d (%s)\n", s->out_csp,
-                       av_color_space_name(s->out_csp));
-            }
-            return AVERROR(EINVAL);
-        }
         redo_rgb2yuv = 1;
     }
 
@@ -687,6 +668,26 @@ static av_cold int init(AVFilterContext *ctx)
 {
     ColorSpaceContext *s = ctx->priv;
 
+    s->out_csp  = s->user_csp == AVCOL_SPC_UNSPECIFIED ?
+                  default_csp[FFMIN(s->user_all, CS_NB)] : s->user_csp;
+    s->out_lumacoef = av_csp_luma_coeffs_from_avcsp(s->out_csp);
+    if (!s->out_lumacoef) {
+        if (s->out_csp == AVCOL_SPC_UNSPECIFIED) {
+            if (s->user_all == CS_UNSPECIFIED) {
+                av_log(ctx, AV_LOG_ERROR,
+                       "Please specify output colorspace\n");
+            } else {
+                av_log(ctx, AV_LOG_ERROR,
+                       "Unsupported output color property %d\n", s->user_all);
+            }
+        } else {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Unsupported output colorspace %d (%s)\n", s->out_csp,
+                   av_color_space_name(s->out_csp));
+        }
+        return AVERROR(EINVAL);
+    }
+
     ff_colorspacedsp_init(&s->dsp);
 
     return 0;
@@ -735,6 +736,9 @@ static int filter_frame(AVFilterLink *link, AVFrame *in)
         return res;
     }
 
+    out->colorspace =      s->out_csp;
+    out->color_range =     s->user_rng == AVCOL_RANGE_UNSPECIFIED ?
+                           in->color_range : s->user_rng;
     out->color_primaries = s->user_prm == AVCOL_PRI_UNSPECIFIED ?
                            default_prm[FFMIN(s->user_all, CS_NB)] : s->user_prm;
     if (s->user_trc == AVCOL_TRC_UNSPECIFIED) {
@@ -746,10 +750,6 @@ static int filter_frame(AVFilterLink *link, AVFrame *in)
     } else {
         out->color_trc   = s->user_trc;
     }
-    out->colorspace      = s->user_csp == AVCOL_SPC_UNSPECIFIED ?
-                           default_csp[FFMIN(s->user_all, CS_NB)] : s->user_csp;
-    out->color_range     = s->user_rng == AVCOL_RANGE_UNSPECIFIED ?
-                           in->color_range : s->user_rng;
     if (rgb_sz != s->rgb_sz) {
         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(out->format);
         int uvw = in->width >> desc->log2_chroma_w;
@@ -841,8 +841,18 @@ static int query_formats(AVFilterContext *ctx)
     };
     int res;
     ColorSpaceContext *s = ctx->priv;
+    AVFilterLink *outlink = ctx->outputs[0];
     AVFilterFormats *formats = ff_make_format_list(pix_fmts);
 
+    res = ff_formats_ref(ff_make_formats_list_singleton(s->out_csp), &outlink->incfg.color_spaces);
+    if (res < 0)
+        return res;
+    if (s->user_rng != AVCOL_RANGE_UNSPECIFIED) {
+        res = ff_formats_ref(ff_make_formats_list_singleton(s->user_rng), &outlink->incfg.color_ranges);
+        if (res < 0)
+            return res;
+    }
+
     if (!formats)
         return AVERROR(ENOMEM);
     if (s->user_format == AV_PIX_FMT_NONE)
@@ -855,7 +865,7 @@ static int query_formats(AVFilterContext *ctx)
     if (res < 0)
         return res;
 
-    return ff_formats_ref(formats, &ctx->outputs[0]->incfg.formats);
+    return ff_formats_ref(formats, &outlink->incfg.formats);
 }
 
 static int config_props(AVFilterLink *outlink)