diff --git a/SpineViewer/ViewModels/Exporters/CustomFFmpegExporterViewModel.cs b/SpineViewer/ViewModels/Exporters/CustomFFmpegExporterViewModel.cs
index bb90b00..6dc050b 100644
--- a/SpineViewer/ViewModels/Exporters/CustomFFmpegExporterViewModel.cs
+++ b/SpineViewer/ViewModels/Exporters/CustomFFmpegExporterViewModel.cs
@@ -92,7 +92,7 @@ namespace SpineViewer.ViewModels.Exporters
                 var output = Path.Combine(_outputDir!, filename);
 
                 if (_autoResolution) SetAutoResolutionAnimated(exporter, spines);
-                if (_duration < 0) exporter.Duration = spines.Select(sp => sp.GetAnimationMaxDuration()).DefaultIfEmpty(0).Max();
+                exporter.Duration = _duration >= 0 ? _duration : spines.Select(sp => sp.GetAnimationMaxDuration()).DefaultIfEmpty(0).Max();
 
                 exporter.ProgressReporter = (total, done, text) =>
                 {
diff --git a/SpineViewer/ViewModels/Exporters/FFmpegVideoExporterViewModel.cs b/SpineViewer/ViewModels/Exporters/FFmpegVideoExporterViewModel.cs
index 5af1e78..97468ee 100644
--- a/SpineViewer/ViewModels/Exporters/FFmpegVideoExporterViewModel.cs
+++ b/SpineViewer/ViewModels/Exporters/FFmpegVideoExporterViewModel.cs
@@ -83,7 +83,7 @@ namespace SpineViewer.ViewModels.Exporters
                 var output = Path.Combine(_outputDir!, filename);
 
                 if (_autoResolution) SetAutoResolutionAnimated(exporter, spines);
-                if (_duration < 0) exporter.Duration = spines.Select(sp => sp.GetAnimationMaxDuration()).DefaultIfEmpty(0).Max();
+                exporter.Duration = _duration >= 0 ? _duration : spines.Select(sp => sp.GetAnimationMaxDuration()).DefaultIfEmpty(0).Max();
 
                 exporter.ProgressReporter = (total, done, text) =>
                 {
diff --git a/SpineViewer/ViewModels/Exporters/FrameSequenceExporterViewModel.cs b/SpineViewer/ViewModels/Exporters/FrameSequenceExporterViewModel.cs
index ac91c91..68fcdd6 100644
--- a/SpineViewer/ViewModels/Exporters/FrameSequenceExporterViewModel.cs
+++ b/SpineViewer/ViewModels/Exporters/FrameSequenceExporterViewModel.cs
@@ -56,12 +56,12 @@ namespace SpineViewer.ViewModels.Exporters
                 var output = Path.Combine(_outputDir!, folderName);
 
                 if (_autoResolution) SetAutoResolutionAnimated(exporter, spines);
-                if (_duration < 0) exporter.Duration = spines.Select(sp => sp.GetAnimationMaxDuration()).DefaultIfEmpty(0).Max();
+                exporter.Duration = _duration >= 0 ? _duration : spines.Select(sp => sp.GetAnimationMaxDuration()).DefaultIfEmpty(0).Max();
 
                 exporter.ProgressReporter = (total, done, text) =>
                 {
-                    pr.Total = total; 
-                    pr.Done = done; 
+                    pr.Total = total;
+                    pr.Done = done;
                     pr.ProgressText = text;
                     _vmMain.ProgressValue = pr.Done / pr.Total;
                 };