perf: lower seek time for thumbnails

src/previews/video.rs

@@ -32,7 +32,7 @@ impl<'a> Previewable for VideoPath<'a> {
             .args(["-threads", "1"])
             .args(["-i", &self.0.to_string_lossy()])
             .args(["-vframes", "1"])
-            .args(["-ss", &(300f64.min(duration / 4.0)).to_string()])
+            .args(["-ss", &(90f64.min(duration / 2.0)).to_string()])
             .arg(&*outfile.path().to_string_lossy())
             .arg("-y")
             .output()?;