diff --git a/skills/watch/scripts/frames.py b/skills/watch/scripts/frames.py
index 18f0aa9..d8194e7 100755
--- a/skills/watch/scripts/frames.py
+++ b/skills/watch/scripts/frames.py
@@ -117,9 +117,10 @@ def _sync_option(executable: str) -> tuple[str, str]:
     result = run_text([executable, "-hide_banner", "-h", "full"], timeout=30)
     if result.returncode == 0:
         help_text = result.stdout + result.stderr
-        if re.search(r"(?m)^\s*-fps_mode\s", help_text):
+        # FFmpeg 9 lists options with stream specifiers, e.g. "-fps_mode[:<stream_spec>]".
+        if re.search(r"(?m)^\s*-fps_mode\b", help_text):
             return "-fps_mode", "vfr"
-        if re.search(r"(?m)^\s*-vsync\s", help_text):
+        if re.search(r"(?m)^\s*-vsync\b", help_text):
             return "-vsync", "vfr"
     raise SystemExit(f"{executable} did not advertise -fps_mode or -vsync; check the FFmpeg installation. {diagnostic(result.stderr)}")
 
diff --git a/tests/test_runtime.py b/tests/test_runtime.py
index 0f5d8c8..9feba73 100644
--- a/tests/test_runtime.py
+++ b/tests/test_runtime.py
@@ -53,7 +53,7 @@ def test_invalid_probe_metadata(monkeypatch, data):
         frames.get_metadata('test.mp4')
 
 
-@pytest.mark.parametrize('help_text,expected', [('-vsync  set video sync', '-vsync'), ('-fps_mode  set fps\n-vsync  set sync', '-fps_mode'), ('-fps_mode  set fps', '-fps_mode'), ('unknown option: fps_mode', None)])
+@pytest.mark.parametrize('help_text,expected', [('-vsync  set video sync', '-vsync'), ('-fps_mode  set fps\n-vsync  set sync', '-fps_mode'), ('-fps_mode  set fps', '-fps_mode'), ('-fps_mode[:<stream_spec>]  set framerate mode for matching video streams', '-fps_mode'), ('unknown option: fps_mode', None)])
 def test_sync_capability_probe(monkeypatch, help_text, expected):
     calls = []
     def help_run(cmd, **kw):