In Recast for Business, open Stream Inputs and choose + Stream Input. Pick RTMP or SRT — the choice is fixed once the input is created.
Recast then shows the values your encoder needs. Copy them from there rather than retyping them:
Note that an SRT input labels its credential STREAM ID, not Stream Key. It is the same value, under the name SRT uses for it.
Then confirm all three of these, or your stream will be refused:
A new stream input is switched off. Recast switches it on only when it is attached to a live, non-draft video.
Not on the device. Destinations are configured in the LiveU Solo web portal (solo.liveu.tv), and the unit collects them when it comes online. Set up your Recast destination before you leave for the venue — you do not want to be doing this on a phone in a car park.
SRT on the Solo needs both of the following:
LiveU Reliable Transport (LRT) is the Solo's own bonding protocol. The unit sends LRT to the LiveU cloud, and the cloud converts it to SRT for delivery to Recast. This means SRT is not a device-to-Mux connection — it is a device-to-cloud-to-Mux connection, which has consequences described below.
Without an LRT subscription, use RTMP.
Bonded cellular bandwidth varies constantly. 720p is the sensible default for a Solo; reserve 1080p for situations where you have tested the bonded uplink at the venue and know it holds up.
Use no more than 50% of your measured upload bandwidth. On bonded cellular, measure with the Solo's own bandwidth display at the venue, at the time of day you will be streaming — cell congestion at 3pm tells you nothing about 8pm.
Which URL? Recast displays rtmp://global-live.mux.com:5222/app as your RTMP STREAM URL, and that works. This guide uses rtmps:// on port 443 instead: it is the same Mux ingest wrapped in TLS, so your stream key is not sent in clear text, and port 443 passes through restrictive venue networks that block port 5222. Use whichever your encoder supports.
Recastrtmps://global-live.mux.com:443/appThe Solo supports RTMPS in the Generic destination type, so use the rtmps:// URL on port 443.
The Solo offers an RTMP Direct mode that bypasses the LiveU cloud and sends straight from the device. It removes a hop, but it also removes bonding — you are on a single interface. Use it only when you have one reliable connection and no LRT subscription.
Requires firmware 7.1 or later and an active LRT subscription.
Recast SRTsrt://global-live.mux.com:6001Key length must be 128-bit if the portal exposes the choice. Mux requires it.
Because the SRT leg runs from the LiveU cloud to Mux — not from the device — SRT does not improve the resilience of the cellular link itself. That job is already done by LRT between the unit and the cloud.
What SRT buys you is a more robust cloud-to-Mux hop than RTMP provides. That is worth having, but if your problem is patchy cellular at the venue, SRT is not the fix. More modems, better antenna placement, or a lower bitrate is.
The delay includes a cloud hop. LiveU adds its own latency between the unit and the cloud, configurable in the portal, on top of Recast's standard latency. Expect noticeably more than 30 seconds end to end. This is normal.
Check your data allowance. A 3500 kbps stream is roughly 1.5 GB per hour, per bonded modem carrying a share of it. Long events on metered SIMs get expensive quickly, and a SIM hitting its cap mid-event looks exactly like a coverage failure.
Modem placement matters more than settings. The Solo's antennas are directional enough that moving the unit a metre, or off a metal surface, can change available bandwidth substantially. Do this before lowering the bitrate.
Configure destinations in advance. Portal changes take effect when the unit next contacts the cloud, which is not instant.
One protocol per stream input. A Recast stream input is created as either RTMP or SRT and cannot be switched afterwards.
Check the stream input is attached to a video and that the video is not a draft. The Solo will report a healthy stream to the LiveU cloud while Recast rejects the final delivery.
Then wait a full 40 seconds — the extra cloud hop means longer than usual.
Look at the modem status on the unit's display. Losing modems means losing bandwidth, and the Solo will reduce quality to compensate before it drops.
Move the unit. Then reduce the bitrate a tier. Then check SIM data allowances.
You have 30 minutes to reconnect before Recast treats the stream as ended.
On a bonded uplink this nearly always means the bitrate is too high for the cellular conditions. Drop to 480p rather than persisting at 720p — a stable lower resolution looks considerably better than an unstable higher one.
Confirm the audio source on the Solo's input — the unit takes embedded SDI or HDMI audio, or an analogue input, and selecting the wrong one produces silence.
Prefer embedded audio so the audio and video share a clock across the cloud hop.
Include the unit model and firmware version, whether you have an LRT subscription, the destination type, the number of modems connected, and the bitrate you were sending.
More detail: Recast live ingest reference
