Use correct fixed frame rate for metrics

Author: n00mkrad

ff-utils-winforms/IO/IoUtils.cs

@@ -351,7 +351,7 @@ public static async Task<Fraction> GetVideoFramerate (string path)
 			}
 			catch
             {
-				Logger.Log("Failed to read FPS - Please enter it manually.");
+				Logger.Log("Failed to read FPS.");
 			}
 
 			return fps;

ff-utils-winforms/UI/Tasks/UtilGetMetrics.cs

@@ -42,9 +42,10 @@ public static async Task Run(bool fixRate = true)
                 form.ShowDialog();
                 Program.mainForm.SetMetricsVarsFromForm(form);
 
-                Logger.Log($"Getting metrics for {Path.GetFileName(vidLq)} compared against {Path.GetFileName(vidHq)}.");
+                Logger.Log($"Getting metrics for {Path.GetFileName(vidLq)} compared against {Path.GetFileName(vidHq)}...");
 
-                string r = fixRate ? "-r 24" : "";
+                Fraction fps = await IoUtils.GetVideoFramerate(vidLq);
+                string r = fixRate ? $"-r {(fps.GetFloat() > 0f ? fps.ToString() : "24")}" : "";
                 string f = await GetAlignFilters();
                 FfmpegOutputHandler.overrideTargetDurationMs = await FfmpegCommands.GetDurationMs(vidLq);