Sweep/vgdeband: cap x264 at ENCODE_THREADS (2) so conversions stop starving Jellyfin and the live portal

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

bin/vgdeband.sh

@@ -27,7 +27,7 @@ print(d.get("source","none"), 1 if d.get("band_removed") else 0, d.get("timecode
   log "deband $f  (${w}px wide -> crop ${band} rows; tc=$tc)"
   nice -n 15 ionice -c 3 ffmpeg -nostdin -hide_banner -loglevel error -y -i "$f" \
     -map 0:v:0 -map '0:a?' \
-    -c:v libx264 -preset veryfast -crf 18 -maxrate 30M -bufsize 60M -pix_fmt yuv420p -profile:v high \
+    -c:v libx264 -preset veryfast -crf 18 -maxrate 30M -bufsize 60M -pix_fmt yuv420p -profile:v high -threads "${ENCODE_THREADS:-2}" \
     -vf "crop=iw:ih-${band}:0:0" -fps_mode passthrough -c:a copy \
     "${tcargs[@]}" -movflags +faststart -f mp4 "$tmp"
   rc=$?; d1=$(dur "$f"); d2=$(dur "$tmp")