Covers the Teradek Prism range — Prism Rack, Prism Flex, Prism Mobile and Prism Jetpack. This is Teradek's current encoder line and what they point former VidiU owners at.
Prism has a full SRT stream mode of its own, so it reaches Recast directly on either protocol with nothing else in the path. You do not need Teradek Core unless you want what Core itself adds.
Every model is both an encoder and a decoder depending on how it is configured. This guide only concerns the encoder side. All of them support H.264 and HEVC, and all of them do SRT and RTMP(S).
The setup is the same across the range. Only how you reach the web interface differs, and how much bonding you have available.
In Recast for Business, open Stream Inputs and choose + Stream Input. Pick RTMP or SRT — the choice is fixed once the input is created. Prism does both well, so this is a real choice; see [which should you use](#srt-or-rtmp-on-a-prism) below.
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.
172.16.1.1, or use its Ethernet IPThe default password is prism followed by the last five digits of the serial number — for example prism12345.
On a Rack unit, use one Ethernet port at a time. Both ports active at once is not a supported configuration.
Prism is one of the few encoders where SRT is the straightforward choice rather than the ambitious one. Its SRT defaults already match what Recast wants, and the field set is complete.
Pick SRT if you are on cellular, venue wifi, or any link you do not control. Pick RTMP(S) if you are on a wired connection you trust, or if the venue blocks outbound UDP — which is common enough to be worth testing before the day.
Use no more than 50% of your measured upload bandwidth, measured at the venue on the connection you will use.
Set the codec to H.264 before anything else. Prism encodes HEVC as well as H.264, and Teradek's own note is unambiguous: "Your device must be set to H.264 to stream to any streaming platform." Mux live ingest does not accept HEVC. A Prism left on HEVC will encode happily, connect, and deliver nothing playable — which looks like a Recast problem and is not.
This is the recommended path for a Prism.
global-live.mux.com60010 — let the encoder assign one500 ms, or higher on cellularEuropean users can substitute eu-west.live.mux.com as the Host.
Most of these are already the defaults. Teradek ships SRT set to Caller, 128-bit keys and 500 ms latency — the three values that most often need changing on other manufacturers' encoders. Check them rather than assuming, but expect to be changing Host, Port, Stream ID and Passphrase only.
Encryption must be on. Recast always issues an SRT passphrase, and Mux refuses an unencrypted connection. Key size must be 128 bits; 192 or 256 will fail the handshake.
The Interface field matters on a multi-homed unit. A Prism Mobile with modems and ethernet will send over whichever interface you select here, not over all of them. If you want the stream to leave by a specific SIM or by the wired connection, set it explicitly rather than leaving it to chance.
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.
rtmps://global-live.mux.com:443/appEuropean users can substitute rtmps://eu-west.live.mux.com/app. If the unit will not accept an rtmps:// URL on your firmware, use rtmp://global-live.mux.com:5222/app.
Turn Auto Reconnect on. Recast holds your stream slot open for 30 minutes after a drop, and reconnecting inside that window resumes the same recording. Auto Reconnect is what makes that automatic rather than something you have to notice and fix.
Leave Adaptive Bitrate off to match the CBR guidance above — a predictable stream is a reliable one. The exception is cellular, where a picture that dips in quality beats one that stalls. If you turn it on, set your tier's bitrate as the ceiling rather than the target.
User Agent can be left at its default. If a connection is refused for no other apparent reason, FMLE is the more broadly compatible of the two options.
HEVC is the trap on this range. It is the reason to buy a Prism and the reason a Prism stream fails. Mux live ingest is H.264 only. Confirm the codec before every event on a unit you share with anyone.
Bonding needs Core, and Core is a different path. Prism's bonded cellular needs a Teradek endpoint at the far end to reassemble the connections, which means Core. Mux cannot do that. So a direct stream to Recast uses one interface, however many the unit has. If you need genuine bonding, use the Teradek Core guide and accept the second hop.
Multiple SIMs is not the same as bonding. A Prism Mobile has two internal modems taking two SIMs each. Streaming direct to Recast, that gives you a choice of network and a fallback, not combined bandwidth.
Do not chase low latency. Recast streams run at standard latency (20–30 seconds) by design. Prism can do far better point-to-point, but that is not what is happening here.
One protocol per stream input. A Recast stream input is created as either RTMP or SRT and cannot be switched afterwards.
The unit is also a decoder. Configuration screens exist for both roles. Make sure you are setting the encoder's streaming output and not the decoder's ingest — the SRT field names are nearly identical on both.
Check the stream input is attached to a video and that the video is not a draft. The Prism will report a healthy stream while Recast rejects it.
Then check the codec is H.264, not HEVC. This is the most common cause on this range and it produces exactly this symptom.
Then wait a full 30 seconds before concluding anything.
Check the SRT statistics or the RTMP bitrate graph. A gap between the configured bitrate and what is actually leaving the unit means the network is the constraint — drop a tier, or raise the SRT latency to give it more room.
On a multi-homed unit, confirm the Interface setting is the connection you think it is.
You have 30 minutes to reconnect before Recast treats the stream as ended. Auto Reconnect on the RTMP path handles this for you.
Reduce the bitrate one tier. If Adaptive Bitrate is on, that is expected behaviour under congestion rather than a fault.
Confirm AAC-LC at 48 kHz stereo, and that the correct embedded SDI audio pair is selected.
Prefer embedded audio over a discrete input so audio and video share a clock.
Include the model and firmware version, the codec in use, the protocol, which interface the stream is leaving by, and whether Core is in the path. Say explicitly whether the Streaming tab reports the stream as running.
More detail: Recast live ingest reference
