Loop Player

Turn an old Android screen into a looping video sign. Loop Player is a lightweight app that plays the videos in one folder full screen, forever: no playback controls, no status bar, no ads, no accounts, no cloud. It suits cheap tabletop signage players, old tablets, digital photo frames and Android TV boxes running Android 5.0 or newer.

It started as the replacement player for the FYD-835S tabletop sign, but nothing in it is specific to that device.

What it does

• Plays every .mp4, .mkv and .webm in Movies/loop/ on the device's storage (/sdcard/Movies/loop/), in name order, forever. A single file loops seamlessly inside the media player.
• Swipe up to choose what loops. A panel of thumbnails slides up:
  • Tap a video to add it to the loop or take it out. The number on each tile is its place in the order, so tapping three videos plays them back to back in that order.
  • Hold a video to loop just that one (the panel closes and it starts at once).
  • All loops every video in the folder, including ones added later.
  • Tags (the row of buttons under the header, if your videos have tags): tap one to loop every video with that tag, including ones tagged later, and the panel shows just those. Tap more to add them; tap All to go back to everything. See Tags for how to set them.
  • Shuffle plays the loop in a random order, reshuffled each time round (without the same video twice in a row). Off plays it in order.
  • Swipe down, tap above the panel or press Back to close it; it also closes by itself after 30 seconds. Unchosen videos are greyed out, and the one playing now is marked. The choice is remembered across restarts.
• Swipe left to skip to the next video, swipe right to go back to the one before.
• Swipe down to go to the device's home screen, when that's another app (say, a launcher of your own with more things to do on the screen).
• Interludes (optional): a video that stays out of the loop and comes up on its own every so many videos, such as a "sign our guestbook" card. Tapping it can open an app; when that app closes, the loop carries on with the next video. See Interludes.
• Double-tap: sound off/on. It's remembered across restarts.
• Hold a finger down for 3 seconds: opens the menu.
  • Choose videos (the same panel as swiping up)
  • Phone remote on/off (see below)
  • Sound on/off
  • Picture: fit the whole video (letterbox, the default) or fill the screen (crop)
  • Home screen: makes Loop Player the launcher, so it opens at boot and whenever Home is pressed (kiosk mode)
  • Sleep: the screen goes black at its lowest backlight and playback pauses; tap the screen to wake it
  • Reload videos, Android settings, Exit player
• Starts at boot. On Android 9 and older, it does this on its own. On Android 10+, turn on Home screen in the menu, because newer Android won't let apps open a screen at boot any other way.
• Rotation follows the device (and its rotation lock).

Phone remote and schedule

Turn on Phone remote in the hold menu. The screen shows an address such as http://192.168.1.50:8080 and a 6-digit PIN. Open the address in your phone's browser on the same Wi-Fi, enter the PIN once, and you can:

• pick what loops (tap to build the loop, ▶ to loop one, All, tags, Shuffle), with the same rules as the swipe-up panel, and skip back or forward
• tag videos (Tags… then tap a video)
• turn the sound on or off and set the volume
• set the brightness, fit or fill, and put the screen to sleep or wake it
• add videos from your phone, or delete them
• open another app on the device, or bring Loop Player back
• set a schedule: a list of times of day, each of which can turn the screen on or off, set the brightness, turn the sound on or off and change what loops. For example: 17:30 on at full brightness with every video, 21:00 dim to 40% and loop just two, 23:30 off. Each time takes effect once a day; anything you change by hand in between stays until the next time.

Good to know:

• The remote is off until you turn it on, and only the hold menu can turn it on. It answers only devices on your local network, over plain HTTP. Your phone signs in once with the PIN and then stays signed in. Five wrong PINs lock that phone or computer out for a minute, and 20 from anywhere in ten minutes pause all PIN tries; phones already signed in keep working. Anyone on your Wi-Fi who sees the PIN can use it.
• To see the address and PIN again, hold 3 s: they're on the Phone remote line of the menu. New PIN (just below it) makes a fresh PIN, signs out every phone and clears any lockout.
• The schedule and the remote work while Loop Player is open. Sleep dims the backlight to its minimum, since apps can't switch the panel fully off.
• Adding and deleting videos needs storage access on Android 6–10 (Loop Player asks when you turn the remote on).
• Opening other apps from the remote works on Android 9 and older; Android 10+ may block it while Loop Player isn't on screen.

Install

1. Download LoopPlayer.apk from Releases and install it: open it on the device (allow installs from unknown sources), or from a computer run adb install -r LoopPlayer.apk.
2. Open Loop Player and allow access to videos. On Android 13+, choose Allow all; with "selected only" it can't see new files.
3. Put videos in Movies/loop/ with USB file transfer, a file manager, or:

   adb shell mkdir -p /sdcard/Movies/loop
   adb push my-loop.mp4 /sdcard/Movies/loop/

4. Hold 3 s → Reload videos (or restart the app).

Tags

Tags group videos so you can loop a set (say, everything for Halloween) without picking them one by one. They live in tags.json next to the videos in Movies/loop/:

{
  "order": ["Halloween", "Christmas", "Music"],
  "videos": {
    "pumpkins.mp4": ["Halloween"],
    "carols.mp4": ["Christmas", "Music"]
  }
}

order sets the order of the tag buttons; tags not listed come after, most-used first. A video can have any number of tags, and tags match regardless of case. Edit the file on a computer and push it with adb push tags.json /sdcard/Movies/loop/, then reload, or tag videos from the phone remote (which writes the same file). Videos without tags still play under All.

Interludes

An interlude is a video that comes up between the others instead of being part of the loop: once every so many videos, whatever is looping (All, tags or picks). Add them to the same tags.json:

"interludes": {
  "guestbook.mp4": {"every": 5, "open": "com.example.guestbook"}
}

• every: how many videos play between showings (5 here: it comes up after every fifth video).
• open (optional): an app to open when someone taps the screen during the interlude, by package name, or a particular screen of it as package/.ActivityName. When that app closes (or brings Loop Player back), the loop carries on with the next video.

Interludes don't appear in the swipe-up panel or the remote's video list. A single video looping on its own plays no interludes, since it never ends.

Remote control over ADB

adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --ez reload true   # rescan the folder
adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --es play intro.mp4        # loop just this one
adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --es playlist "a.mp4,b.mp4"  # these, in order
adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --ez all true      # every video
adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --es tags "Halloween,Music"  # these tags
adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --ez shuffle true  # or false (in order)
adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --ez next true     # skip ahead
adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --ez previous true # back one
adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --ez mute true     # or false
adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --ez fill true     # or false (fit)
adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --ez home true     # or false
adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --ez remote false  # phone remote off
adb shell am start -n io.github.robbiemueller.loopplayer/.PlayerActivity --ez sleep true    # screen to sleep, or false

The phone remote's JSON API works from scripts too: send the PIN as an X-Pin header, and an X-Remote: 1 header on anything that changes something, e.g. curl -H "X-Pin: 123456" http://192.168.1.50:8080/api/state. The endpoints are listed at the top of RemoteServer.java.

Tips for the video

• Encode it for the screen. Match the panel's resolution and use plain H.264 (Main profile) in an MP4. Old hardware decoders choke on HEVC, 10-bit and very high bitrates:

  ffmpeg -i in.mp4 -vf scale=1280:-2 -c:v libx264 -profile:v main -crf 20 -pix_fmt yuv420p \
    -c:a aac -b:a 160k -movflags +faststart out.mp4

• Seamless loops: start and end on the same frame (black is easiest) with the sound faded out.
• Tiny speakers: master loud (about -13 LUFS) and roll off everything below about 140 Hz.

Tested

On an FYD-835S (Rockchip RK3126, Android 6.0.1), we tested:

• the permission prompt
• playback and seamless looping
• the swipe-up picker (tap to add or remove, hold to loop one, All, tags, Shuffle, swipe down to close)
• swiping left and right to skip ahead and back
• an interlude every five videos, opening an app on a tap and carrying on when it closes; swiping down to another home screen
• the phone remote: PIN, sessions and lockout, picking videos, sound, brightness, sleep and wake, uploading and deleting
• the schedule (sleep, wake, brightness and loop changes firing at their times)
• double-tap mute
• fit and fill
• the hold menu
• the home-screen chooser

It builds for Android 15 (target SDK 35), but hasn't been run on Android 10+ hardware yet. Reports welcome.

Known quirk: on that device's old Launcher3, uninstalling Loop Player right after offering it as a home screen made Launcher3 crash once ("Launcher3 has stopped" → OK). It recovered by itself.

Build

No Gradle or Android Studio project: just the SDK command-line tools (javac, d8, aapt2, zipalign, apksigner) from an Android Studio install.

./build.sh --install     # macOS / Linux (untested so far)
.\build.ps1 -Install     # Windows (tested)

The first build creates local.keystore here (git-ignored). Releases are signed with a different key, so to switch from a release to your own build, uninstall first.

License

MIT