src/video/ffmpeg.rs

@@ -273,7 +273,7 @@ pub async fn generate_preview_clip(input_file: &str, output_file: &str) -> Resul
         let interval = duration / segment_count as f64;
 
         let vf = format!(
-            "select='lt(mod(t,{:.4}),1)',setpts=N/FRAME_RATE/TB,scale=-2:480",
+            "select='lt(mod(t,{:.4}),1)',setpts=N/30/TB,scale=-2:480",
             interval
         );
         let af = format!(
@@ -285,6 +285,10 @@ pub async fn generate_preview_clip(input_file: &str, output_file: &str) -> Resul
         cmd.args(["-af", &af]);
     }
 
+    // Force 30fps output so high-framerate sources (60fps) don't play back
+    // at double speed due to select/setpts timestamp mismatches.
+    cmd.args(["-r", "30"]);
+
     // Use NVENC for encoding when available, otherwise fall back to libx264
     if use_nvenc {
         cmd.args(["-c:v", "h264_nvenc", "-preset", "p4", "-cq:v", "28"]);