diff --git a/aegisub/src/ass_file.cpp b/aegisub/src/ass_file.cpp
index da5692f55..534f8746a 100644
--- a/aegisub/src/ass_file.cpp
+++ b/aegisub/src/ass_file.cpp
@@ -455,8 +455,6 @@ void AssFile::LoadDefault(bool defline) {
 	AddLine("Title: Default Aegisub file","[Script Info]",version);
 	AddLine("ScriptType: v4.00+","[Script Info]",version);
 	AddLine("WrapStyle: 0", "[Script Info]",version);
-	AddLine("PlayResX: 640","[Script Info]",version);
-	AddLine("PlayResY: 480","[Script Info]",version);
 	AddLine("ScaledBorderAndShadow: yes","[Script Info]",version);
 	AddLine("Collisions: Normal","[Script Info]",version);
 	AddLine("","[Script Info]",version);
diff --git a/aegisub/src/frame_main.cpp b/aegisub/src/frame_main.cpp
index 9d375b1d6..16a68a40f 100644
--- a/aegisub/src/frame_main.cpp
+++ b/aegisub/src/frame_main.cpp
@@ -407,29 +407,6 @@ void FrameMain::OnVideoOpen() {
 	else if (vidx*3*zoom > windowSize.GetX()*2 || vidy*4*zoom > windowSize.GetY()*3)
 		context->videoDisplay->SetZoom(zoom * .5);
 
-	// Check that the video size matches the script video size specified
-	int scriptx = context->ass->GetScriptInfoAsInt("PlayResX");
-	int scripty = context->ass->GetScriptInfoAsInt("PlayResY");
-	if (scriptx != vidx || scripty != vidy) {
-		switch (OPT_GET("Video/Check Script Res")->GetInt()) {
-			case 1:
-				// Ask to change on mismatch
-				if (wxMessageBox(wxString::Format(_("The resolution of the loaded video and the resolution specified for the subtitles don't match.\n\nVideo resolution:\t%d x %d\nScript resolution:\t%d x %d\n\nChange subtitles resolution to match video?"), vidx, vidy, scriptx, scripty), _("Resolution mismatch"), wxYES_NO, this) != wxYES)
-					break;
-				// Fallthrough to case 2
-			case 2:
-				// Always change script res
-				context->ass->SetScriptInfo("PlayResX", wxString::Format("%d", vidx));
-				context->ass->SetScriptInfo("PlayResY", wxString::Format("%d", vidy));
-				context->ass->Commit(_("Change script resolution"), AssFile::COMMIT_SCRIPTINFO);
-				break;
-			case 0:
-			default:
-				// Never change
-				break;
-		}
-	}
-
 	SetDisplayMode(1,-1);
 
 	if (OPT_GET("Video/Detached/Enabled")->GetBool() && !context->detachedVideo)
diff --git a/aegisub/src/video_context.cpp b/aegisub/src/video_context.cpp
index 33e9d8e9f..1b1036a3a 100644
--- a/aegisub/src/video_context.cpp
+++ b/aegisub/src/video_context.cpp
@@ -159,6 +159,37 @@ void VideoContext::SetVideo(const wxString &filename) {
 		videoProvider = provider->GetVideoProvider();
 		videoFile = filename;
 
+		// Check that the script resolution matches the video resolution
+		int sx = context->ass->GetScriptInfoAsInt("PlayResX");
+		int sy = context->ass->GetScriptInfoAsInt("PlayResY");
+		int vx = GetWidth();
+		int vy = GetHeight();
+
+		// If the script resolution hasn't been set at all just force it to the
+		// video resolution
+		if (sx == 0 && sy == 0) {
+			context->ass->SetScriptInfo("PlayResX", wxString::Format("%d", vx));
+			context->ass->SetScriptInfo("PlayResY", wxString::Format("%d", vy));
+			context->ass->Commit(_("Change script resolution"), AssFile::COMMIT_SCRIPTINFO);
+		}
+		// If it has been set to something other than a multiple of the video
+		// resolution, ask the user if they want it to be fixed
+		else if (sx % vx != 0 || sy % vy != 0) {
+			switch (OPT_GET("Video/Check Script Res")->GetInt()) {
+			case 1: // Ask to change on mismatch
+				if (wxMessageBox(wxString::Format(_("The resolution of the loaded video and the resolution specified for the subtitles don't match.\n\nVideo resolution:\t%d x %d\nScript resolution:\t%d x %d\n\nChange subtitles resolution to match video?"), vx, vy, sx, sy), _("Resolution mismatch"), wxYES_NO, context->parent) != wxYES)
+					break;
+				// Fallthrough to case 2
+			case 2: // Always change script res
+				context->ass->SetScriptInfo("PlayResX", wxString::Format("%d", vx));
+				context->ass->SetScriptInfo("PlayResY", wxString::Format("%d", vy));
+				context->ass->Commit(_("change script resolution"), AssFile::COMMIT_SCRIPTINFO);
+				break;
+			default: // Never change
+				break;
+			}
+		}
+
 		keyFrames = videoProvider->GetKeyFrames();
 
 		// Set frame rate