HDMI output

What it is for

A lobby display, a day-room television, a waiting-room screen. Somewhere a single fixed channel needs to be on all day, the display is close enough to the appliance to be reached with a cable, and installing a set-top box or a small-form-factor PC to do it would be disproportionate.

It is not a monitoring feature. If you want to check that a channel is working, use the browser preview or the UDP bitrate figure — see Monitoring and metrics.

Configuration

There are two fields and a switch.

Name

A label for the output, used in the status display and the log view. It is not written into any transport stream, because nothing here produces one.

URL

The source to play. This can be one of the multicast groups Castmux is already producing, or any other URL the appliance can reach.

Active

Starts and stops playback. Turning it off stops the player; turning it on starts it and keeps it running.

Status and logs

The output reports whether it is currently playing and how long it has been doing so. Uptime is the more useful of the two: a status that reads as playing but an uptime that keeps resetting to a few seconds means the player is crashing and being restarted, which is a different fault from one that will not start at all.

A log view shows the player’s own output. This is where to look when a URL plays in VLC on a laptop but not here — usually a codec the appliance’s display pipeline cannot handle, or a source the appliance cannot reach.

Automatic restart

If the player exits — a crash, a source that disappears, a stream that ends — it is restarted automatically. A screen in a public area that has been showing a blank display since some point on Tuesday is a fault nobody reports and everybody sees, so recovering without intervention is the sensible default. The uptime figure is what tells you it has been happening.

Independence from UDP channels

The HDMI output is a separate process from the channels. It does not occupy a multicast group, it does not appear in a DVB-C multiplex, and it has no destination address.

One consequence is worth knowing if you point it at one of your own multicast groups: the HDMI output joins that group like any other receiver, so it counts as a viewer for on-demand streaming. An on-demand channel with the HDMI output pointed at it will never stop, which is correct behaviour and occasionally surprising.

Output device

Video goes to the appliance’s display device and audio is carried over HDMI. There is no separate audio output selection.

One source at a time

The HDMI output plays a single stream. There is no video wall, no mosaic and no scheduled rotation between sources. If you need two screens showing two channels, you need two appliances or a set-top box for the second screen.