diff --git a/internal/api/resolver_query_configuration.go b/internal/api/resolver_query_configuration.go
index cf2c0e3cc..0098c5769 100644
--- a/internal/api/resolver_query_configuration.go
+++ b/internal/api/resolver_query_configuration.go
@@ -104,6 +104,7 @@ func makeConfigGeneralResult() *ConfigGeneralResult {
 		PreviewAudio:                  config.GetPreviewAudio(),
 		PreviewSegments:               config.GetPreviewSegments(),
 		PreviewSegmentDuration:        config.GetPreviewSegmentDuration(),
+		MaxMarkerPreviewDuration:      config.GetMaxMarkerPreviewDuration(),
 		PreviewExcludeStart:           config.GetPreviewExcludeStart(),
 		PreviewExcludeEnd:             config.GetPreviewExcludeEnd(),
 		PreviewPreset:                 config.GetPreviewPreset(),
diff --git a/internal/manager/config/config.go b/internal/manager/config/config.go
index 05dcf97a4..1c75f4719 100644
--- a/internal/manager/config/config.go
+++ b/internal/manager/config/config.go
@@ -120,7 +120,7 @@ const (
 	previewExcludeEndDefault = "0"
 
 	MaxMarkerPreviewDuration        = "max_marker_preview_duration"
-	maxMarkerPreviewDurationDefault = 20
+	maxMarkerPreviewDurationDefault = 0
 
 	WriteImageThumbnails        = "write_image_thumbnails"
 	writeImageThumbnailsDefault = true
diff --git a/pkg/scene/generate/marker_preview.go b/pkg/scene/generate/marker_preview.go
index 83faec2fa..0f7e612a6 100644
--- a/pkg/scene/generate/marker_preview.go
+++ b/pkg/scene/generate/marker_preview.go
@@ -39,16 +39,19 @@ func (g Generator) MarkerPreviewVideo(ctx context.Context, input string, hash st
 
 	// Honor the marker's explicit interval when present and positive, capped
 	// by the configured safety ceiling. maxDuration <= 0 disables the ceiling.
+	// Non-positive intervals are treated as "no video wanted" and skipped —
+	// if the user intentionally set end = start they didn't want a preview,
+	// and if it's a data mistake we'd rather surface it than silently default.
 	if endSeconds != nil {
 		interval := *endSeconds - seconds
-		if interval > 0 {
-			if maxDuration <= 0 || interval <= float64(maxDuration) {
-				duration = interval
-			} else {
-				duration = float64(maxDuration)
-			}
+		if interval <= 0 {
+			logger.Warnf("[generator] marker at %.2fs has non-positive interval (end=%.2f); skipping video preview generation", seconds, *endSeconds)
+			return nil
+		}
+		if maxDuration <= 0 || interval <= float64(maxDuration) {
+			duration = interval
 		} else {
-			logger.Warnf("[generator] marker at %.2fs has non-positive interval (end=%.2f); falling back to %ds default", seconds, *endSeconds, markerPreviewDefaultDuration)
+			duration = float64(maxDuration)
 		}
 	}
 
diff --git a/ui/v2.5/src/locales/en-GB.json b/ui/v2.5/src/locales/en-GB.json
index 3cc754928..d0e044dcc 100644
--- a/ui/v2.5/src/locales/en-GB.json
+++ b/ui/v2.5/src/locales/en-GB.json
@@ -418,7 +418,7 @@
       "include_audio_desc": "Includes audio stream when generating previews.",
       "include_audio_head": "Include audio",
       "logging": "Logging",
-      "max_marker_preview_duration_desc": "Ceiling (in seconds) applied to generated marker preview videos when the marker has an explicit end time. Protects against unexpectedly long previews from imports or data entry mistakes. Set to 0 to disable the ceiling and honor the marker's end time verbatim.",
+      "max_marker_preview_duration_desc": "Optional ceiling (in seconds) for marker preview videos with explicit end times. Default is 0 (no ceiling, the marker's end time is honored verbatim). Set a positive value to cap preview duration as a safety against imports or data entry mistakes. Markers without an end time use a fixed 20-second default, unaffected by this setting.",
       "max_marker_preview_duration_head": "Max marker preview duration",
       "maximum_streaming_transcode_size_desc": "Maximum size for transcoded streams.",
       "maximum_streaming_transcode_size_head": "Maximum streaming transcode size",