diff --git a/toolchain/tv/tv-sync.sh b/toolchain/tv/tv-sync.sh
new file mode 100755
index 0000000000..35e6dea05c
--- /dev/null
+++ b/toolchain/tv/tv-sync.sh
@@ -0,0 +1,102 @@
+#!/bin/sh
+# tv-sync.sh — read, set, or measure a TV station's audio delay, fast.
+#
+# The A/V offset is one number (AV_OFFSET seconds, itsoffset on the pulse
+# input; positive = delay audio, i.e. push early audio later). Tuning it
+# by hand meant ssh + sed + restart every time; this is one line.
+#
+#   tv-sync.sh <station>              show current offset (+ live encoder arg)
+#   tv-sync.sh <station> <ms>         set offset to N milliseconds, restart
+#   tv-sync.sh <station> +<ms>        nudge by N ms (e.g. +20, -15)
+#   tv-sync.sh <station> measure      rig-side A/B card measurement (no Chrome,
+#                                     no YouTube) — prints the true baseline
+#
+#   station = wgtv | actv    host fixed to jasellite (the rig box)
+#
+# Setting restarts the one station (a few-second stream blip); measure
+# swaps in the test card for ~70s then restores. YouTube adds its own
+# viewer-side skew on top of the rig number, so the ear stays the final
+# judge — but this makes each guess cost one command, not five.
+set -eu
+HOST=jasellite
+UNIT="${1:?usage: tv-sync.sh <wgtv|actv> [ms|+ms|measure]}"
+ENV="$UNIT/$UNIT.env"
+
+# ── read ──────────────────────────────────────────────────────────────
+if [ $# -lt 2 ]; then
+  ssh "$HOST" "sh -c '
+    printf \"env:  \"; grep \"^AV_OFFSET=\" $ENV | tail -1
+    printf \"live: \"; ps -eo args | grep -o -- \"itsoffset [0-9.]*\" | sort -u | tail -1'"
+  exit 0
+fi
+
+ARG="$2"
+
+# ── measure (rig-side A/B card) ───────────────────────────────────────
+if [ "$ARG" = "measure" ]; then
+  SIZE=$(ssh "$HOST" "grep '^SIZE=' $UNIT/$UNIT.env | tail -1 | cut -d= -f2")
+  DISP=$(ssh "$HOST" "grep '^DISPLAY_NUM=' $UNIT/$UNIT.env | tail -1 | cut -d= -f2")
+  SINK=$(ssh "$HOST" "grep '^SINK=' $UNIT/$UNIT.env | tail -1 | cut -d= -f2")
+  [ -n "$SIZE" ] || SIZE=1280x720
+  [ -n "$DISP" ] || DISP=:99
+  [ -n "$SINK" ] || SINK=tvsink
+  echo "▸ measuring $UNIT ($SIZE $DISP $SINK) via the sync card — ~70s, station restores after"
+  ssh "$HOST" "sh -c '
+    systemctl --user stop $UNIT-watchdog.timer $UNIT; sleep 2
+    grep -v \"^URL=\" $ENV > /tmp/tvsync.env
+    echo URL=file:///home/jas/wgtv/sync-test.html >> /tmp/tvsync.env
+    echo UNMUTE_CLICK=1 >> /tmp/tvsync.env
+    nohup sh $UNIT/rig.sh /tmp/tvsync.env > $UNIT/sync-rig.log 2>&1 &
+    sleep 25
+    ffmpeg -v error -thread_queue_size 1024 -use_wallclock_as_timestamps 1 \
+      -f x11grab -framerate 30 -video_size $SIZE -i $DISP \
+      -thread_queue_size 1024 -use_wallclock_as_timestamps 1 \
+      -f pulse -fragment_size 1024 -i ${SINK}.monitor \
+      -af aresample=async=1 -fps_mode cfr -t 30 \
+      -c:v libx264 -preset veryfast -pix_fmt yuv420p -c:a aac -y /tmp/tvsync.mp4
+    pkill -f \"user-data-dir=/home/jas/.tv-rig-chrom[e] \" 2>/dev/null || true
+    pkill -f \"Xvfb ${DISP%%:*}:${DISP##*:}\" 2>/dev/null || true
+    pkill -f -- \"-i ${DISP%%x*} \" 2>/dev/null || true
+    sleep 2
+    systemctl --user start $UNIT $UNIT-watchdog.timer
+    echo ===FLASH===
+    ffmpeg -i /tmp/tvsync.mp4 -vf blackdetect=d=0.15:pix_th=0.10 -an -f null - 2>&1 | grep -o \"black_end:[0-9.]*\" | cut -d: -f2 | tr \"\n\" \" \"
+    echo; echo ===BEEP===
+    ffmpeg -i /tmp/tvsync.mp4 -af silencedetect=n=-25dB:d=0.25 -vn -f null - 2>&1 | grep -o \"silence_end: [0-9.]*\" | awk \"{print \\\$2}\" | tr \"\n\" \" \"
+    echo'" 2>/dev/null | FL_BP_READER=1 python3 -c '
+import sys
+fl=bp=None
+for ln in sys.stdin:
+    ln=ln.strip()
+    if ln=="===FLASH===": mode="f"; continue
+    if ln=="===BEEP===": mode="b"; continue
+    vals=[float(x) for x in ln.split()] if ln and ln[0].isdigit() else None
+    if vals and mode=="f": fl=vals
+    if vals and mode=="b": bp=vals
+if not fl or not bp:
+    print("✗ measurement failed (no card events captured)"); sys.exit(1)
+o=sorted((b-min(fl,key=lambda f:abs(f-b)))*1000 for b in bp if abs(b-min(fl,key=lambda f:abs(f-b)))<0.5)
+m=o[len(o)//2]
+print(f"rig A/V offset: {m:+.0f} ms ({\"audio LATE\" if m>0 else \"audio EARLY\"}); spread {o[0]:+.0f}…{o[-1]:+.0f}")
+print(f"suggested: tv-sync.sh {\"'\"$UNIT\"'\"} {int(round(-m))}   (delay audio to cancel it)")
+'
+  exit 0
+fi
+
+# ── set / nudge ───────────────────────────────────────────────────────
+case "$ARG" in
+  +*|-*) # nudge
+    CUR=$(ssh "$HOST" "grep '^AV_OFFSET=' $ENV | tail -1 | cut -d= -f2" || echo 0)
+    [ -n "$CUR" ] || CUR=0
+    NEW=$(awk "BEGIN{printf \"%.3f\", $CUR + ($ARG)/1000}")
+    ;;
+  *) NEW=$(awk "BEGIN{printf \"%.3f\", $ARG/1000}") ;;
+esac
+
+echo "▸ $UNIT AV_OFFSET → ${NEW}s (audio delayed ${NEW}s) — restarting"
+ssh "$HOST" "sh -c '
+  grep -q \"^AV_OFFSET=\" $ENV && sed -i \"s/^AV_OFFSET=.*/AV_OFFSET=$NEW/\" $ENV || echo AV_OFFSET=$NEW >> $ENV
+  systemctl --user restart $UNIT
+  sleep 24
+  systemctl --user is-active $UNIT
+  ps -eo args | grep -o -- \"itsoffset $NEW\" | head -1'"