Chase from Art-Net

In addition to chasing audio LTC, LTCast can follow timecode that arrives over the network as Art-Net OpTimeCode packets — from another instance of LTCast, or from any device that sends Art-Net timecode. That lets you run a multi-machine setup over standard Ethernet or Wi-Fi with no audio cable between the machines.

Enabling Art-Net network input

Open Settings → Timecode In → Chase and tick Art-Net Network Input. LTCast starts listening on UDP port 6454. When the first packet arrives from a new sender, a message tells you which address it came from. No configuration is needed on the sending side. If the port cannot be opened, LTCast shows the error and unticks the box again.

Like the rest of the Chase tab, the control is dimmed unless the session is Pro (an active trial counts).

How Art-Net chase works

The incoming timecode goes to the same chase engine as an audio LTC input, so everything on Chasing external LTC applies: the timecode display shows the external time, the setlist song is found through the LTC scanned in the song files (songs without LTC cannot be chased yet), triggers fire as the external time passes them, and local audio follows only if Output audio while chasing is on. The sending machine is the master; the receiving machine is the follower. Chase itself does not send the received time on to MTC, Art-Net or OSC — see the TC Bridge section below.

You can have the LTC input device and the Art-Net input active at the same time, but there is no priority or source lock: both feed the chase engine as their frames arrive, so two different masters would fight over the clock. Use one master at a time.

Packets from this computer are ignored

LTCast drops Art-Net packets that come from any of this computer's own IP addresses, including 127.0.0.1. That is what prevents a loop when Art-Net output and Art-Net input are both on here. The side effect is that another program running on the same computer cannot be the source either — the master has to be a different machine. LTCast also limits each sender to 200 packets per second, which is far above any timecode stream.

Art-Net Input Offset

The Art-Net Input Offset (frames) field adds a fixed number of frames, from −99 to +99, to the received timecode before it is used. A positive value makes the timecode later; a negative value makes it earlier. Use it to:

• compensate for network latency between the sending and receiving machine, or
• apply an intentional sync offset when the two machines need to be deliberately out of phase (for example, one machine drives displays that are physically offset from the stage).

Start with 0 and adjust based on the drift you observe on your own network. The offset applies to Art-Net input only, not to an audio LTC input, and it also applies to anything TC Bridge forwards from the Art-Net input.

Art-Net input and TC Bridge

With Art-Net input on, TC Bridge (if it is on) also forwards the received timecode, whether or not chase is enabled. It forwards to MTC and OSC only — never back out as Art-Net, because that would send the same timecode back onto the network it came from.