Device compatibility

Read this first

This is not a “supported devices” list. The TreeT viewer runs on standard web technology, so it generally works on devices that aren’t listed here.

What this page records is the devices we actually tested and what came out of it — and, more importantly, how you can judge a device yourself. One screen is all you need to look at.

Why not just publish a list

New devices keep appearing, and the same model behaves differently on different OS builds. “It’s on the list, so it works” goes stale fast. So we give you the test as well — that doesn’t go stale.

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1. Devices we tested

Android

Device	Android	Playback	Sync	Recommended playback mode
Galaxy S9 (SM-G960N)	10	✅	✅ 28 ms	Native (fine to switch from the default)
LG G6	9	✅	✅ 21 ms	🔴 웹뷰 (WebView) — native has a problem
Galaxy S8+ · S9+	9–10	✅	—	Default (automatic → 웹뷰 / WebView)

The Sync column is the median position error when several screens are kept in step. It is how far apart the same video runs on two devices — anything at or under 30 ms is invisible to the eye.

Desktop and others

Device	What we tested	Sync
Windows PC	Running in production	✅ 25 ms
Raspberry Pi 5 (Debian 13)	Running in production	✅ 26 ms
Ubuntu PC (x86-64)	Boot and playback	—

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2. 🔴 Limitations worth knowing

Being on the list doesn’t mean every device behaves the same. We only record what actually bit us.

2-a. Some devices need a different video playback mode

An Android device has two ways to play video — 웹뷰 (WebView) and 네이티브 (native). The default is automatic, and automatic means WebView; a value set per device wins. You choose it under Devices → that device → TreeTview tab → [Edit] on the 화면설정 (Display settings) group → 영상 재생 방식 (video playback mode).

On some devices, native can’t keep several screens in step

Some devices acknowledge the fine playback-speed adjustment but never actually apply it. When that happens, multiple screens cannot be kept aligned.

The three devices we tested split like this:

Device	On native	After switching to 웹뷰 (WebView)
Galaxy S9	✅ holds at 28 ms	— (no need to switch)
LG G6	🔴 stuck 2 seconds off	✅ 21 ms
Galaxy Note 4	🔴 195 ms off	✅ 24 ms

⚠️ The Note 4 gave these results with a short test video, but with a real 1080p schedule on site its WebView couldn’t open the video properly (15 errors in 40 minutes · p95 offset 4951 ms). Played natively, the same schedule ran 45 minutes with 0 errors · p95 98 ms — so native is now the default (below).

⭐ These are all Android, and they still differ. You can’t predict it from the spec sheet — you have to measure. Section 3 is how.

Then why not put everything on WebView

WebView isn’t always better. Native is the path that plays video more smoothly on weaker hardware. So we recommend leaving the default (automatic) and switching only when you see a problem.

2-b. Very old devices may never show a picture

The viewer runs on the web engine build that ships inside the device. If that is too old, the app can’t start at all. ⚠️ The deciding factor is the web engine build, not the Android version — two devices on the same Android 7 can differ.

👉 If you install the app and it never moves past a black screen, this is the case. Tell your administrator.

⚠️ The supported minimum is Android 7.0. The app does not install on Android 6 or earlier. Android 6 devices that already have it stay on the earlier version and receive no further updates — even on that version, remote commands and screen capture (the video area comes out black) did not work.

2-c. Video codecs

Devices differ in which video formats they can play. H.264 + AAC (mp4) is the safest choice. See the video encoding guide for details.

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When the screen turns off and on — playback shows over the lock screen

The Android player shows playback over the lock screen, leaving the device lock (PIN etc.) as it is (from TreeTviewAndroid 2026.9.321). So playback stays visible even with a lock set, and you need to unlock the device to operate it. On earlier versions, once the screen turned off and on, the lock screen could stay on top of playback — in that case unlock the device once on site.

The CMS screen capture shows only the player window. So even when the capture looks normal, another window (such as the lock screen) may be covering the real screen.

3. 🔵 Judging a device that isn’t listed

Connect one and just use it. Then check these three things.

① Does a picture appear

Install it, switch it on, and see whether content plays. If it does, the basics work. If it never moves past a black screen, see 2-b.

② If you run several screens in step — check the sync

This only applies if you align several devices on the same video. Skip it if you use one screen.

By eye: put two devices side by side and play the same video. If they look the same to you, that’s enough. If they visibly differ, switch 영상 재생 방식 (video playback mode) to 웹뷰 (WebView) and look again after two minutes.

🔵 Use the test video when you compare by eye — ordinary footage hides the difference

Comparing with your own content hides a mismatch. A landscape or a logo looks the same to a person even a tenth of a second apart.

So we ship a video with milliseconds printed on it — it is in your media library as TreeT 싱크 시험 (120초·30fps) (TreeT sync test, 120 seconds). Schedule it on both devices and watch them side by side.

If it is not in the list

When you install the CMS, it is there from the start. If it was deleted, upload TreeT-synctest-1080p30-120s.webm from the seed folder of the CMS install package in Content management; it is the same video.

Three things are on screen at once. Any one of them is enough — pick whichever reads easiest.

What to look at	How to read it
The large number 00:01.750	The two screens are fine if the numbers are the same, or one step apart
The sweeping bar	Fine if the two bars are level with each other. Easier to catch than the digits
The blinking band	Fine if both bands brighten together. Visible from across the room, out of the corner of your eye

⚠️ Why “one step apart” is normal: video shows one second as 30 pictures. One picture is 33 ms, so nothing finer than that can appear on screen at all. 👉 One step = normal · several steps = worth looking into

⚠️ If devices play videos with different frame rates, don’t compare the FRAME counter in the corner — at the same instant a 60 fps video shows 001800 and a 30 fps video 000900. The three things in the table above (big number · bar · band) follow the same clock, so they compare directly even when the frame rates differ.

🔴 If they differ a lot (numbers tens or hundreds apart), switch 영상 재생 방식 (video playback mode) in 2-a to 웹뷰 (WebView) and look again after two minutes.

By number: ask your administrator for that device’s sync report. It contains this line:

옮김 9회(배속놓고 7)

What you see	What it means
옮김 0회, or no parentheses	✅ That device keeps in step
🔴 (배속놓고 N) with N of 1 or more	That device cannot stay in step on native — switch it to 웹뷰 (WebView)

③ Leave it running for a while

Some device problems only show up after a day or two (heat, memory, power). Leave it on for at least a day and check that the picture keeps playing.

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4. What to tell us

If you test a new device, please send us the result. It saves the next person from repeating it.

• The device name and its Android version (Settings → About phone)
• Which of ①②③ above it failed at
• If it failed, the exact text shown on screen

Why the exact text

“It doesn’t work” has ten possible causes. One line from the screen usually settles it on the spot.