Blackmagic Streaming Encoder 4K SRT setup: send SRT to Callaba Gateway
Written by Iurii Pakholkov
Founder of Callaba. Building cloud video tools for SRT, RTMP, WebRTC, NDI, live routing, monitoring, recording, and production workflows.
Release: Callaba 8.4
Blackmagic Streaming Encoder 4K can send an SRT contribution feed directly to a cloud receiver. Use this setup when Streaming Encoder 4K is at the venue and Callaba is the cloud SRT receiver for monitoring, recording, routing, multiview, or restreaming. The practical path is SDI into the encoder, outbound SRT over Ethernet or tethered mobile data, then Callaba as the SRT gateway.
Blackmagic’s public specifications list SRT and RTMP for this model. They also list H.264/H.265 streaming for SRT on the 4K unit. I recommend starting with H.264 HD before moving to H.265 or UHD.
Quick answer
To use Blackmagic Streaming Encoder 4K with SRT, set Streaming Encoder 4K as the SRT Caller and send the stream to a cloud SRT Listener. In this guide, Callaba works as the SRT gateway, receiver, monitor, recorder, and routing layer.
The Blackmagic encoder sends one contribution feed into Callaba. After ingest, Callaba can preview, record, route, restream, and feed multiview in parallel, not as mandatory sequential steps.
- SDI sourceCamera or switcher
- Streaming Encoder 4KSRT caller / outbound push
- Callaba GatewaySRT listener / receiver
- Preview
- Record
- Route
- Restream
- Multiview
What this setup does
This Blackmagic Streaming Encoder 4K SRT setup turns the unit into a venue-side contribution encoder. Callaba is the public SRT server, listener, and cloud receiver. After the SRT connection is stable, the same received feed can be used for monitoring, recording, routing, web playback, multiview, or restreaming without asking the encoder to send multiple copies.
What this model can and cannot do in this workflow
- Confirmed: official Blackmagic specs list SRT and RTMP direct streaming for Streaming Encoder 4K.
- Confirmed: SRT is listed with H.264 and H.265; RTMP is listed with H.264.
- Confirmed: the model has a 12G-SDI input and supports HD and Ultra HD workflows up to 2160p60 in the published specs.
- Confirmed: embedded SDI audio is part of the workflow; Blackmagic release notes also mention 16-channel embedded audio support for this 4K encoder line.
- Confirmed: Ethernet is used for streaming and configuration, and USB-C can be used for setup, webcam output, or 4G/5G phone tethering.
- Confirmed: the unit has SDI loop/monitor outputs and HDMI monitoring, useful for checking local source status before blaming the network.
- Caveat: public Blackmagic material confirms SRT key/passphrase and SRT stream-id XML support, but does not clearly publish listener or rendezvous operation for this encoder. Treat outbound caller/push to Callaba as the normal production path.
- Limitation: do not plan Streaming Encoder 4K as a native NDI, RTSP, or ST 2110 source. Those are not listed for this exact model in the official material reviewed.
- Model distinction: Streaming Decoder 4K is the return-feed/receive side of the same family. This page is for the encoder sending SRT into Callaba, not for decoding Callaba back to SDI or HDMI.
Recommended workflow
Use the encoder as the SRT sender at the venue and keep Callaba reachable on a public UDP port. This avoids inbound firewall requirements at the venue. In searched terms: Streaming Encoder 4K is the SRT caller, Callaba is the SRT listener, receiver, server, and gateway.
If SRT is not available on the installed unit or a destination requires only RTMP, use RTMP as the confirmed fallback. I would not build an RTMPS workflow for this model unless the installed unit exposes it or Blackmagic confirms it for that firmware.
When not to use this setup
If your only destination is a platform that accepts RTMP and you do not need cloud monitoring, recording, routing, or multiview, direct RTMP may be enough. If the encoder and destination are in the same rack, local SDI may be simpler. If the production requires NDI or RTSP, add a separate converter or bridge; do not treat Streaming Encoder 4K as a native NDI or RTSP source.
Before you start
- Update or confirm the installed Blackmagic Streaming software/firmware before the event.
- Connect a stable SDI source to the 12G-SDI input and verify local monitor output.
- Use wired Ethernet where possible; mobile tethering is useful, but test it under venue conditions.
- Start with H.264 1080p or 720p. Move to H.265/UHD only after ingest, recording, playback, and restream targets are confirmed.
- Confirm SRT Stream ID/key, passphrase, and compatible SRT behavior on both sides. Stream ID and passphrase values are case-sensitive and whitespace-sensitive.
Create the Callaba ingest
In Callaba, create an SRT server and choose a UDP port that is open to the internet. Set the listener mode for contribution ingest, add a Stream ID or key if your workflow uses one, and set a passphrase if encryption is required. Copy the public host, port, Stream ID/key, and passphrase exactly. A copied newline or trailing space can break the SRT handshake.
Configure Streaming Encoder 4K
Open Blackmagic Streaming Setup and configure a custom SRT destination for the Callaba server URL. The Blackmagic manual describes RTMP/SRT server URLs plus SRT Key and Passphrase fields, and the streaming XML format supports SRT stream-id extension elements. Put the encoder on air only after the source, network, URL, key, and passphrase have been checked.
Settings table
| Where | What to do / field to fill | First-test value | Why / check |
|---|---|---|---|
| Callaba SRT server | Create SRT server and choose UDP port | One dedicated public UDP port | Callaba must be reachable by the venue encoder. |
| Callaba SRT server | Set Stream ID or access key if used | Simple event-specific value | Must match the Blackmagic SRT Key or stream-id mapping exactly. |
| Callaba SRT server | Set passphrase if encryption is used | Strong shared passphrase | Match case, spaces, and length on both sides. |
| Blackmagic Streaming Setup | Server URL | srt://your-callaba-host:port | Points the encoder to the Callaba listener. |
| Blackmagic Streaming Setup | SRT Key | Same value as Callaba Stream ID/key | Confirmed field in Blackmagic documentation; avoid trailing spaces. |
| Blackmagic Streaming Setup | Passphrase | Same value as Callaba | Required when encryption is enabled. |
| Blackmagic streaming profile | Codec and resolution | H.264 1080p30 at 4-6 Mb/s | Use H.265 or 2160p only after downstream checks pass. |
| Blackmagic monitor / front workflow | Go ON AIR | After Callaba is listening | Look for SRT protocol status, stable data rate, and no cache growth. |
Monitoring
In Callaba, check incoming bitrate, connection uptime, RTT, packet loss, retransmits, preview, and audio meters. On the Blackmagic side, use the monitor status for input signal, audio, data rate, cache, and protocol. If the device shows SRT but Callaba has no incoming bitrate, check firewall and destination URL first.
Failover and local ingest options
For production events, plan what happens if the main encoder, venue uplink, or primary contribution path fails. Callaba can be part of that continuity plan without changing the basic Blackmagic Streaming Encoder 4K ingest workflow.
Recording and playback
Once ingest is stable, record in Callaba and test the playback path that the production will actually use. H.265 and UHD can be attractive on this 4K encoder, but every downstream recorder, player, decoder, and restream destination must support that codec and resolution. For first line checks, H.264 HD is faster to diagnose.
Troubleshooting
| Symptom | Check in Callaba | Check on device | Likely fix |
|---|---|---|---|
| No connection | Server listening, UDP port open, no incoming session | Server URL, ON AIR state, network route | Correct host/port and open the UDP path to Callaba. |
| Handshake fails | Stream ID/key and passphrase values | SRT Key and Passphrase fields | Remove copied newlines, trailing spaces, or capitalization differences. |
| Connects then drops | RTT, packet loss, retransmits, uptime | Cache/data rate and uplink quality | Raise practical latency if exposed, reduce bitrate, or improve uplink. |
| Video but no audio | Audio meters and recording audio track | Embedded SDI audio and channel routing | Confirm the SDI source embeds audio and the route handles the expected channels. |
| Preview fails with HEVC | Codec shown on received stream | H.265 profile/UHD setting | Switch to H.264 HD, then retest HEVC with compatible players and outputs. |
| Unclear SRT compatibility | Server build/support information | Blackmagic firmware and support notes | Confirm compatible SRT behavior with vendor support before the event. |
Official references
Vendor references
- Blackmagic Streaming Processors tech specs
- Blackmagic Streaming Processors product page
- Blackmagic Streaming Processors monitoring page
- Blackmagic Streaming Processors manual
- Blackmagic Design support center
Protocol references
Callaba resources
FAQ
Does Blackmagic Streaming Encoder 4K support SRT to cloud?
Yes. Blackmagic’s official specifications list SRT for Streaming Encoder 4K, including H.264/H.265 use. In this workflow, Callaba is the cloud SRT receiver.
Is Streaming Encoder 4K an SRT caller, listener, or receiver?
For this setup, treat it as the outbound SRT caller/push encoder. Callaba is the SRT listener, server, gateway, and receiver. Public Blackmagic docs reviewed do not clearly confirm listener or rendezvous operation for the encoder.
How should I enter the SRT Stream ID and passphrase?
Match Callaba exactly. The Blackmagic manual describes SRT Key and Passphrase fields and SRT stream-id support in the streaming XML format. These values are case-sensitive and whitespace-sensitive.
Can I use RTMP or RTMPS instead?
RTMP is confirmed in the official specs and is a practical H.264 fallback. RTMPS was not confirmed in the official Blackmagic material reviewed, so do not rely on it unless the installed unit exposes it or Blackmagic confirms it.
Does Streaming Encoder 4K support native NDI or RTSP?
No official NDI or RTSP output is listed for this exact model. Use SRT or RTMP directly, or add a separate conversion bridge if a production system requires NDI or RTSP.
Should I use H.265 and 2160p immediately?
Not for the first test. Start with H.264 HD, confirm ingest and monitoring, then test H.265 or UHD only if the receiver, recorder, player, and restream targets support it.
Next steps
Create one Callaba SRT server, test the Blackmagic feed with H.264 HD, confirm audio and connection statistics, then add recording, multiview, routing, or restreaming as parallel outputs. Before a live job, rehearse the exact Stream ID/key, passphrase, codec, bitrate, and firewall path that will be used on site.
Try Callaba Gateway with Blackmagic Streaming Encoder 4K SRT
Create an SRT server in Callaba, send the device feed to the gateway, and check the received stream. After ingest is stable, use Callaba outputs for preview, recording, restreaming, multiview, playback, routing, or API workflows as parallel downstream options.