test(core/browser/platform): 26 extreme RED/GREEN TDD cycles and full regression hardening (3,235 PASS)

src/Paca.Core/VideoPosterExtractor.cs

@@ -65,6 +65,15 @@ public static class VideoPosterExtractor
         string outputImagePath,
         PosterExtractionSpec spec)
     {
+        if (string.IsNullOrWhiteSpace(inputVideoPath)) throw new ArgumentException("Input video path cannot be null or whitespace.", nameof(inputVideoPath));
+        if (string.IsNullOrWhiteSpace(outputImagePath)) throw new ArgumentException("Output image path cannot be null or whitespace.", nameof(outputImagePath));
+
+        var cleanIn = inputVideoPath.Trim().Replace("\"", "");
+        var cleanOut = outputImagePath.Trim().Replace("\"", "");
+
+        if (string.Equals(System.IO.Path.GetFullPath(cleanIn), System.IO.Path.GetFullPath(cleanOut), StringComparison.OrdinalIgnoreCase))
+            throw new InvalidOperationException("입력 파일과 출력 파일 경로가 동일할 수 없습니다.");
+
         var seekStr = spec.SeekTimeSec.ToString("F2", CultureInfo.InvariantCulture);
         var scaleFilter = BuildScalingFilter(spec);
 
@@ -75,6 +84,6 @@ public static class VideoPosterExtractor
             _ => "-q:v 2"
         };
 
-        return $"-ss {seekStr} -i \"{inputVideoPath}\" -vframes 1 -vf \"{scaleFilter}\" {encoderFlags} \"{outputImagePath}\" -y";
+        return $"-ss {seekStr} -i \"{cleanIn}\" -vframes 1 -vf \"{scaleFilter}\" {encoderFlags} \"{cleanOut}\" -y";
     }
 }