avfilter/vf_stack: use ff_formats_pixdesc_filter()

libavfilter/vf_stack.c

@@ -60,24 +60,21 @@ typedef struct StackContext {
 
 static int query_formats(AVFilterContext *ctx)
 {
-    AVFilterFormats *pix_fmts = NULL;
+    AVFilterFormats *formats = NULL;
     StackContext *s = ctx->priv;
-    int fmt, ret;
+    int ret;
 
     if (s->fillcolor_enable) {
         return ff_set_common_formats(ctx, ff_draw_supported_pixel_formats(0));
     }
 
-    for (fmt = 0; av_pix_fmt_desc_get(fmt); fmt++) {
-        const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
-        if (!(desc->flags & AV_PIX_FMT_FLAG_PAL ||
-              desc->flags & AV_PIX_FMT_FLAG_HWACCEL ||
-              desc->flags & AV_PIX_FMT_FLAG_BITSTREAM) &&
-            (ret = ff_add_format(&pix_fmts, fmt)) < 0)
-            return ret;
-    }
-
-    return ff_set_common_formats(ctx, pix_fmts);
+    ret = ff_formats_pixdesc_filter(&formats, 0,
+                                    AV_PIX_FMT_FLAG_HWACCEL |
+                                    AV_PIX_FMT_FLAG_BITSTREAM |
+                                    AV_PIX_FMT_FLAG_PAL);
+    if (ret < 0)
+        return ret;
+    return ff_set_common_formats(ctx, formats);
 }
 
 static av_cold int init(AVFilterContext *ctx)