diff --git a/package.json b/package.json
index 1822e7f..170158d 100644
--- a/package.json
+++ b/package.json
@@ -43,7 +43,7 @@
     "install": "node scripts/install.js",
     "build": "node-gyp rebuild",
     "demo": "node demo/demo.js",
-    "test": "node test/app-lifecycle.js && node test/animation.js && node test/layer-transform.js && node test/contents-gravity.js && node test/contents-center.js && node test/accessibility-display.js && node test/ignores-mouse-events.js && node test/popup-menu.js && node test/pasteboard-write.js && node test/surface-blit.js && node test/surface-faded.js && node test/image-smoothing.js && node test/surface-colorspace.js && node test/video-surface.js && node test/player.js && node test/round-rect-xy.js && node test/clip-rule.js && node test/radial-gradient.js && node test/control-bezels.js && node test/text-features.js && node test/font-from-data.js && node test/text-coverage.js && node test/text-typesetter.js && node test/text-line-height.js && node test/text-line-width.js && node test/text-justify.js && node test/text-scale.js && node test/symbols.js && node test/eventkit-permissions.js && node test/calendars.js && node test/calendar-writes.js && node test/screencolor.js && node test/notifications.js && node test/threaded.js && node test/threaded-verbs.js && node test/threaded-frames.js && node test/threaded-resize.js && node test/ending-worker.js && node test/live-resize.js && node test/window-states.js && node test/threaded-window-states.js && node test/activation-policy.js && node test/last-input.js"
+    "test": "node test/app-lifecycle.js && node test/animation.js && node test/layer-transform.js && node test/contents-gravity.js && node test/contents-center.js && node test/accessibility-display.js && node test/ignores-mouse-events.js && node test/popup-menu.js && node test/pasteboard-write.js && node test/surface-blit.js && node test/surface-faded.js && node test/image-smoothing.js && node test/surface-colorspace.js && node test/video-surface.js && node test/player.js && node test/player-vp9.js && node test/round-rect-xy.js && node test/clip-rule.js && node test/radial-gradient.js && node test/control-bezels.js && node test/text-features.js && node test/font-from-data.js && node test/text-coverage.js && node test/text-typesetter.js && node test/text-line-height.js && node test/text-line-width.js && node test/text-justify.js && node test/text-scale.js && node test/symbols.js && node test/eventkit-permissions.js && node test/calendars.js && node test/calendar-writes.js && node test/screencolor.js && node test/notifications.js && node test/threaded.js && node test/threaded-verbs.js && node test/threaded-frames.js && node test/threaded-resize.js && node test/ending-worker.js && node test/live-resize.js && node test/window-states.js && node test/threaded-window-states.js && node test/activation-policy.js && node test/last-input.js"
   },
   "dependencies": {
     "node-addon-api": "^8.3.0"
diff --git a/src/player.mm b/src/player.mm
index e38c0b8..55a00a9 100644
--- a/src/player.mm
+++ b/src/player.mm
@@ -31,6 +31,7 @@
 
 #include <napi.h>
 #import <AVFoundation/AVFoundation.h>
+#import <VideoToolbox/VideoToolbox.h>
 #import <CoreMedia/CoreMedia.h>
 #import <CoreVideo/CoreVideo.h>
 #import <QuartzCore/QuartzCore.h>
@@ -259,8 +260,21 @@ static void Apply(CALPlayer* p, const PlayerSettings& s) {
   }
 }
 
+// VP9 is one of VideoToolbox's supplemental decoders, which a process has to
+// ask for before AVFoundation can use one. Without this a `vp09` track in an
+// MP4 opens and comes ready, and reports a picture of no size and hands out
+// no frames, with no error anywhere. Asked once, and of nothing on a Mac that
+// has no such decoder: its VP9 then fails as any format it cannot play does.
+static void RegisterSupplementalDecoders() {
+  static dispatch_once_t once;
+  dispatch_once(&once, ^{
+    VTRegisterSupplementalVideoDecoderIfAvailable(kCMVideoCodecType_VP9);
+  });
+}
+
 static Napi::Value CreatePlayer(const Napi::CallbackInfo& info) {
   Napi::Env env = info.Env();
+  RegisterSupplementalDecoders();
   if (!info[0].IsString() || info[0].As<Napi::String>().Utf8Value().empty()) {
     Napi::TypeError::New(env, "createPlayer(url, options): url is a path or a URL string")
         .ThrowAsJavaScriptException();
diff --git a/test/fixtures/clip-vp9.mp4 b/test/fixtures/clip-vp9.mp4
new file mode 100644
index 0000000..ff99078
Binary files /dev/null and b/test/fixtures/clip-vp9.mp4 differ
diff --git a/test/player-vp9.js b/test/player-vp9.js
new file mode 100644
index 0000000..e3f04eb
--- /dev/null
+++ b/test/player-vp9.js
@@ -0,0 +1,77 @@
+'use strict';
+// A `vp09` track in an MP4 (src/player.mm, RegisterSupplementalDecoders):
+// VP9 is a decoder VideoToolbox hands out only to a process that asks, and
+// without one the item comes ready with a picture of no size and no frames
+// ever, with no error. This is that picture having its size, and a seek
+// landing on a frame.
+//
+// test/fixtures/clip-vp9.mp4 is half a second of one colour, 160x90 VP9,
+// written by
+//
+//   ffmpeg -f lavfi -i color=c=0xE07030:s=160x90:r=30:d=0.5 \
+//     -c:v libvpx-vp9 -g 4 -tag:v vp09 -an -movflags +faststart clip-vp9.mp4
+//
+// A Mac with no such decoder has nothing to show, and CI's virtual ones may
+// be that: there, and only there, no picture is news and not a failure.
+//
+// Exits 0 when every expectation held.
+
+const path = require('path');
+const { native } = require('..');
+
+const CLIP = path.join(__dirname, 'fixtures', 'clip-vp9.mp4');
+
+const fail = (msg, ...rest) => {
+  console.error('player-vp9:', msg, ...rest);
+  process.exit(1);
+};
+
+function pumpUntil(pred, ms = 5000) {
+  return new Promise((resolve, reject) => {
+    const deadline = Date.now() + ms;
+    const tick = setInterval(() => {
+      native.pump2();
+      if (pred()) {
+        clearInterval(tick);
+        resolve();
+      } else if (Date.now() > deadline) {
+        clearInterval(tick);
+        reject(new Error('timed out'));
+      }
+    }, 8);
+  });
+}
+
+async function main() {
+  native.initApp();
+  const events = [];
+  native.setBackendEventCallback((ev) => {
+    if (String(ev.type).startsWith('player-')) events.push(ev);
+  });
+  const { id } = native.createPlayer(CLIP, { muted: true });
+  const said = (type) => events.find((e) => e.id === id && e.type === type);
+  await pumpUntil(() => said('player-metadata') || said('player-error')).catch(
+    () => fail('the item never came ready'),
+  );
+  if (said('player-error')) fail('the clip failed', said('player-error'));
+  // the item can come ready first and find its size after
+  await pumpUntil(() => events.some((e) => e.type === 'player-metadata' && e.width), 1500).catch(() => {});
+  const sized = events.find((e) => e.type === 'player-metadata' && e.width);
+  if (!sized) {
+    if (process.env.CI) {
+      console.log('player-vp9: no VP9 decoder on this machine');
+      process.exit(0);
+    }
+    fail('a picture of no size: nothing asked for the VP9 decoder');
+  }
+  if (sized.width !== 160 || sized.height !== 90) fail('its size', sized);
+  native.playerSeek(id, 0.2);
+  await pumpUntil(() => events.some((e) => e.type === 'player-time' && e.currentTime > 0.15)).catch(
+    () => fail('the seek landed nowhere'),
+  );
+  native.releasePlayer(id);
+  console.log('player-vp9: ok');
+  process.exit(0);
+}
+
+main().catch((err) => fail(err));