What crew members see

When a crew member opens the Viewer URL in a browser, they see the LTCast viewer — a live page that follows the show. It is read-only: crew cannot control playback or change anything in LTCast. The two things they can send back are status reports and acknowledgements of alerts. No app, login or plugin is needed.

First visit: the identity screen

The first time a browser opens the page it asks who you are. The crew member enters:

• Name — up to 20 characters. It is attached to the reports they send, so it shows up in the Stage Monitor.
• Role — tap one or more department chips, or leave ALL. The chips are built from the departments used by the cues in the setlist, so they appear once the page has connected to LTCast.
• Show public cues — whether to also show cues that have no department.
• Display fields — switch individual blocks on or off: CLOCK, TIMECODE, ELAPSED, REMAINING, NEXT CUE, UPCOMING, LYRICS. All are on by default.

The choices are saved in that browser. The name button in the page header (it reads ⚙ 設定身份 before a name is set, then shows the name and roles) reopens the screen. The old ?role=lighting&name=Sam address parameters still work, but only to pre-fill a browser that has no saved identity yet.

What is on the screen

From top to bottom:

• Header — the song number and name, always visible; the timecode pill (SMPTE time, with the connection light beside it); a CHASE, FREEWHEEL or LOST pill when LTCast is following an external clock; the state pill PLAYING, PAUSED or STOPPED; and the identity button.
• Pre-show clock — the viewer's own time of day, shown while the show is stopped.
• ELAPSED and REMAINING — two large timers for the current song.
• NEXT — the next cue: its number in the song, department pill, a large countdown, a colour bar and the cue name. During the last 3 seconds before it fires (while playing) the card is highlighted.
• NOW and ON-DECK — the cue currently running, with how long it has been up, and the cue after the next one, with its countdown.
• UPCOMING — the next cues in a list: up to 5 rows when the song has lyrics, and up to 7 rows, fading with distance, when it has none.
• Next-song strip — the next song's name and a countdown to the end of this one.
• Lyrics — when the song has timed lyrics, a scrolling teleprompter: the current line is highlighted and kept in view, lines already sung are dimmed, who sings and stage positions are shown beside the lines. A− and A+ change the text size.
• REPORT — see below.

If the page is connected but no song is loaded, a message says there is no setlist yet, so nobody mistakes the empty timers for a failure.

On a phone held upright everything is one column. On a wide screen, when the song has lyrics, the cues and the report panel sit on the left and the lyrics fill the right.

Roles and which cues show

The cue blocks (NEXT, NOW, ON-DECK, UPCOMING) show the cues whose department matches one of the crew member's roles, plus the cues with no department if Show public cues is on. With no role chosen (ALL) every cue shows. The lyrics, timers and song name are the same for everyone.

Stage reporting

The REPORT panel at the bottom has three status buttons — green 正常 (OK), amber 注意 (WARN) and red 異常 (ERROR) — and a text box for a short message of up to 100 characters. Reports appear in the operator's Stage Monitor, labelled with the crew member's role and name.

• OK and WARN send on a single tap. ERROR must be pressed and held for 1.5 seconds (a ring fills while you hold) so it cannot be sent by accident. On a keyboard, Shift+E sends ERROR directly.
• Tapping the same status again within 3 seconds is ignored, and a button is locked for 1.5 seconds after it fires.
• Typing a message and pressing send reports WARN, unless a status button was tapped in the last 5 seconds — then the message goes with that status.
• If the connection is down, the panel says the report was not delivered. The panel can be collapsed with its header.

Connection light

A small light beside the timecode pill shows how fresh the data is:

• Green — updates are arriving.
• Yellow, "Flying blind Ns · host still up" — nothing has arrived for more than 2 seconds but the connection is open. The page keeps counting by itself: ELAPSED, REMAINING, the countdowns and the lyrics carry on from the last update. Only the SMPTE text in the timecode pill stays at what the last update carried.
• Red, "Host lost — frozen — for reference only" — the connection has been down for more than 4 seconds, or LTCast closed it cleanly. After a clean close nothing is extrapolated any more. A shorter blip is not shown. The page reconnects by itself.

If the connection stays down and the last update is more than 5 minutes old, a red OUT OF SYNC banner appears with the age of that update. Adding ?trust=10 to the address raises the limit to 10 minutes (the value can be 1 to 30; anything under 5 has no effect).

Alerts

When the operator sends an alert or a HOLD, a centred ALERT card appears over the page with the message, over a dark backdrop. If the alert asks for acknowledgement the card has an ACKNOWLEDGE button and stays until it is tapped; otherwise it disappears by itself after 5 seconds.

Compatibility

The viewer works in any modern browser — Chrome, Firefox, Safari and Edge on phones, tablets and laptops. It is designed first for a phone but adapts to larger screens.