vapoursynth: Simplify resize argument logic

The previous logic was actually redundant (except in weird edge cases
where it may cause equally weird behavior) since frame props always take
precedence over explicit arguments in VapourSynth's resize.

src/video_provider_vs.cpp

@@ -104,19 +104,6 @@ std::string colormatrix_description(int colorFamily, int colorRange, int matrix)
 	}
 }
 
-// Adds an argument to the rescaler if the corresponding frameprop does not exist or is set as unspecified
-void VapourSynthVideoProvider::SetResizeArg(VSMap *args, const VSMap *props, const char *arg_name, const char *prop_name, int64_t deflt, int64_t unspecified) {
-	int err;
-	int64_t result = vs.GetAPI()->mapGetInt(props, prop_name, 0, &err);
-	if (err != 0 || result == unspecified) {
-		result = deflt;
-		if (!strcmp(arg_name, "range_in")) {
-			result = result == VSC_RANGE_FULL ? 1 : 0;
-		}
-		vs.GetAPI()->mapSetInt(args, arg_name, result, maAppend);
-	}
-}
-
 VapourSynthVideoProvider::VapourSynthVideoProvider(agi::fs::path const& filename, std::string const& colormatrix, agi::BackgroundRunner *br) try { try {
 	std::lock_guard<std::mutex> lock(vs.GetMutex());
 
@@ -270,12 +257,13 @@ VapourSynthVideoProvider::VapourSynthVideoProvider(agi::fs::path const& filename
 
 		vs.GetAPI()->mapSetNode(args, "clip", node, maAppend);
 		vs.GetAPI()->mapSetInt(args, "format", pfRGB24, maAppend);
-		if (vi->format.colorFamily != cfGray)
-			SetResizeArg(args, props, "matrix_in", "_Matrix", VSC_MATRIX_BT709, VSC_MATRIX_UNSPECIFIED);
-		SetResizeArg(args, props, "transfer_in", "_Transfer", VSC_TRANSFER_BT709, VSC_TRANSFER_UNSPECIFIED);
-		SetResizeArg(args, props, "primaries_in", "_Primaries", VSC_PRIMARIES_BT709, VSC_PRIMARIES_UNSPECIFIED);
-		SetResizeArg(args, props, "range_in", "_ColorRange", VSC_RANGE_LIMITED);
-		SetResizeArg(args, props, "chromaloc_in", "_ChromaLocation", VSC_CHROMA_LEFT);
+
+		// Set defaults for the colorspace parameters.
+		// If the video node has frame props (like if the video is tagged with
+		// some color space), these will override these arguments.
+		vs.GetAPI()->mapSetInt(args, "matrix_in", VSC_MATRIX_BT709, maAppend);
+		vs.GetAPI()->mapSetInt(args, "range_in", 0, maAppend);
+		vs.GetAPI()->mapSetInt(args, "chromaloc_in", VSC_CHROMA_LEFT, maAppend);
 
 		VSMap *result = vs.GetAPI()->invoke(resize, "Bicubic", args);
 		vs.GetAPI()->freeMap(args);