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Watch Together (SyncPlay) ​

Since: 0.17.0

NOTE

Words this app uses: the everyday name for this feature is a watch group — everyone pressing play together, staying in step. SyncPlay is the technical name you'll see in settings, URLs and error messages; "room" appears verbatim inside some screens' buttons and fields (the web dialog literally says "Create room" / "Join room"). They all refer to the same thing.

TL;DR ​

A watch group keeps playback in lockstep across everyone's devices, so household members on different TVs — or friends on the other side of the country — can start, pause and seek as one. One person is the host: their play, pause and seek commands lead, and everyone else follows. Your Phlix server coordinates the group; devices never talk to each other directly.

How It Feels to Use It ​

  1. Someone starts a watch group and picks the title.
  2. Everyone else joins — by picking the group from a list, or typing its ID.
  3. From then on it behaves like one shared remote: when the host pauses, all screens pause; when the host seeks ahead, all screens jump.
  4. If someone's playback drifts more than about two seconds behind or ahead, their player quietly corrects itself — no button needed.

Who is the host? ​

  • The first person in the group is the host.
  • Only the host's playback controls move the group. If you join as a follower and press pause on your own player, the group is unaffected — the player shows you're in a group and defers to the host.
  • The host can pass the lead to another member (host transfer).
  • If the host leaves or their connection drops, the group elects the member who joined earliest as the new host automatically. Nobody votes; the rule is simply "oldest member inherits."

What stays synchronized ​

  • Play / pause — the host starts or stops, everyone does
  • Seek — the host jumps to a scene, everyone jumps (small player-side nudges are tolerated, see drift below)
  • Media item — the group shares one current title, and switching within the group's queue moves everyone

What is NOT synchronized (on purpose) ​

  • Volume — everyone sets their own
  • Playback speed — there is no speed control in group commands; each player runs at its own pace setting
  • Subtitle selection and offset — each viewer picks their own track
  • Audio track selection — each viewer picks their own language

Starting or Joining a Watch Group on the Web ​

  1. Open any title in the web player.
  2. In the player's control bar, click the person icon (its tooltip/label is "SyncPlay"; it reads "In SyncPlay room" once you're inside a group).
  3. The dialog offers "Create or join a room":
    • Create room — type a Room name, click Create. You are the host.
    • Join room — pick a group from the Public rooms list when it shows one, or type the Room ID you were given (it looks like sp_…) and click Join.
  4. A "Joined {name}" confirmation appears and the player's sync controls take over: transport buttons become "Play for everyone" / "Pause for everyone", and rewind/fast-forward move the whole group.

Groups created from the player are always open — there is no password box in the dialog. Room IDs are not guessable, which is the practical privacy control: share the ID only with people you want watching.

A standalone page exists at https://your-server/app/syncplay (after signing in) where you can create a group or join by ID before opening a title. A pre-filled invite link you can send to someone is simply:

text
https://your-server/app/syncplay?room=<room-id>

It opens the join form with the ID filled in — the person still has to be signed in to your server with their own account.

On mobile ​

In the mobile player, tap the SyncPlay button in the overlay controls to open the same create/join dialog (create by name, join by ID).

On Roku ​

During playback press the * / Options key to open the Watch Together overlay. It lists the server's existing groups (name and member count; locked ones marked) — select one to join, or press Create Group (the name comes from your device name; the Roku has no text keyboard for it). Roku has real constraints — see Roku client notes.

Watching from Outside Your Home Network ​

The honest picture:

  • Everyone in a group needs to reach the sync service on your server: TCP port 8097. On your home LAN that just works. From outside, you must expose or tunnel that port (a VPN is the safe default; the same port must be reachable plaintext — see the Roku caveat below).
  • Devices signed in through the Hub synchronize your own devices with each other: Hub-relay rooms are scoped to the server's owner, so a friend signing in with their own Hub account lands in their own room namespace, not yours. For multi-household parties, invite people to your server itself (see Share with friends) and have them connect where they can reach :8097.
  • Roku cannot do encrypted WebSockets at all — its plain-socket API speaks ws:// only, so watch-together on a Roku requires the server's plaintext :8097 to be reachable from the device, and refuses to run in Hub mode.
  • Password-protected groups (created from the admin screen) currently can't be joined from the web dialog, and Roku joins to them fail outright — no client sends a password yet. Create open groups and simply keep the room ID to yourselves.

Staying in Step (Drift and Re-syncing) ​

Followers continuously compare their own clock with the host's reported position (the group exchanges position reports and clock-offset messages; the web client reports its position every five seconds and on every command). Behavior you can actually see:

  • A tiny gap is tolerated — no micro-seeks interrupting anyone.
  • Once a player is more than ~2 seconds off, it seeks to the host automatically.
  • The player's status pill tells you the state: "Synced", "Out of sync", or "Re-syncing…" while a correction lands.

There is deliberately no manual "resync" button — corrections are automatic. If someone is still visibly off, check their connection, or have them leave and rejoin the group.

If a connection drops: web clients retry the sync connection automatically with growing delays; a Roku drop ends that device's session and it re-joins manually.

For Administrators ​

There is no SyncPlay settings panel and no server toggle — watch groups are always on. What Admin → SyncPlay does give you is a group management screen:

  • A table of live groups (name, members, host).
  • Create SyncPlay group — give it a name and, optionally, a password ("Leave empty for an open group"). Note the password caveat above: joining clients can't supply one yet, so prefer open groups.
  • Join SyncPlay group — enter a Group ID (intended for checks and demos).

If you want watch-together to work for remote guests, the port to plan for is 8097/tcp in addition to the usual server port — see Remote access.

Troubleshooting ​

"Playback is out of sync" ​

Wait a moment — automatic correction kicks in at roughly a two-second gap (the status pill shows "Re-syncing…"). If it never settles: that viewer's device has a slow or unstable path to your server's :8097; leave and rejoin, and check reachability.

"Cannot join room" ​

  • Room IDs are the sp_… string from the group's detail or the admin table — names don't work for joining on web/mobile.
  • The joiner must be signed in to the same server as the group.
  • If the group was created from the admin screen with a password, joining fails — no client can enter a password yet (see honest limitation above).
  • If nobody can reach the server's :8097, the sync connection itself can't open.

"Video keeps buffering" ​

Sync playback is not the same as video delivery: buffering is about the media stream, not the group. Try a lower quality for that viewer, or check their bandwidth to the server. The group keeps its logical position even if one player buffers; that player catches up automatically when it can.

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