How to connect Matrox Monarch EDGE to Callaba Gateway using SRT

What this setup does

This workflow sends a live video feed from a Matrox hardware encoder to Callaba Gateway over SRT. Callaba receives the stream in the cloud, then the feed can be monitored, routed, recorded, restreamed, used in a web player, or placed into a browser-based multiview board.

The important part is the relationship between the two sides:

• Matrox Monarch EDGE encodes the SDI input and sends the SRT contribution stream.
• Callaba Gateway listens on a public UDP port and accepts the incoming SRT stream.
• Operators use Callaba to check preview, bitrate, codec, packet loss, recording, restreaming, and failover behavior.

Which Matrox devices this guide fits

The main target for this article is Matrox Monarch EDGE, especially the Monarch EDGE E4 encoder and Monarch EDGE S1 encoder/decoder. Matrox describes the E4 as a remote production encoder that can send up to four synchronized HD streams or one UHD 4Kp60 stream over transport protocols such as SRT. The S1 is a single-channel encoder/decoder for contribution and return-feed workflows.

The same SRT thinking can also apply to other Matrox devices with SRT support, such as parts of the Maevex family, but the user interface and product purpose are different. I would treat Maevex as a separate guide because it is often used in AV, enterprise, control room, and multi-display environments.

Recommended SRT mode: Callaba Listener, Matrox Caller

SRT can use different connection modes. In most cloud ingest workflows, the easiest model is:

• Callaba Gateway: Listener
• Matrox Monarch EDGE: Caller

This keeps the public listening port on the Callaba side. The venue only needs to allow the Matrox unit to send outbound UDP traffic to the Callaba IP and port. This is usually easier than asking the venue to expose an inbound port to the encoder.

A typical SRT URL shape looks like this:

srt://YOUR_CALLABA_IP:10080?mode=caller&latency=200&streamid=matrox-edge-main

Some device interfaces ask for these values as separate fields instead of one URL. That is fine. The logic is the same: destination address, destination UDP port, caller mode, latency, optional stream ID, and optional encryption settings.

Before you start

Prepare the connection before touching the live production profile. This avoids the most common mistake: changing many values at once and then not knowing which one broke the stream.

Step 1: create the SRT listener in Callaba

In Callaba, create a new incoming SRT server for the Matrox feed. The exact module name can differ by your UI version, but the operational idea is the same: Callaba opens a UDP port and waits for the Matrox encoder to connect.

1. Open your Callaba environment.
2. Create a new SRT input or SRT server.
3. Set the role to Listener if the UI exposes this option.
4. Choose a UDP port, for example 10080.
5. Set latency, for example 200 ms as a starting point.
6. Add a stream ID if your routing model uses it.
7. Add the same passphrase that you plan to use on Matrox, if encryption is needed.
8. Open the UDP port in your cloud firewall or security group.

Step 2: configure the Matrox SRT output

Open the Matrox Monarch EDGE web interface and choose the output profile that should send the contribution feed. Firmware versions can change the labels, so look for the SRT output, streaming protocol, or transport settings.

1. Select the SDI input or encoded channel you want to send.
2. Set the streaming protocol to SRT.
3. Set the connection mode to Caller.
4. Enter the Callaba public IP address or DNS name as the destination address.
5. Enter the same destination UDP port that Callaba is listening on.
6. Set latency to the same starting value, or close to it.
7. Enter stream ID if Callaba expects one.
8. Enable encryption only if you have already prepared the same passphrase in Callaba.
9. Start the output and watch for connection state in Callaba.

If the Matrox UI supports multiple outputs per input, start with one clean output first. After the first feed is stable, duplicate the settings for backup, lower-resolution monitoring, or a second Callaba destination.

Settings table

This table is the fastest way to avoid mismatches. The words in the Matrox interface can differ, but the values must describe the same SRT connection.

Codec and bitrate notes

A successful SRT connection does not automatically mean the media is right. SRT moves the stream; the encoder settings still decide whether the video is usable downstream.

For the first test, use a conservative profile:

• Codec: H.264 for the first connection test.
• Resolution: 1080p or the native source resolution you expect to process.
• Frame rate: match the production format.
• Bitrate: start lower than your uplink limit, then increase after stability is confirmed.
• Audio: confirm embedded audio is enabled and mapped to the output profile.

After the first clean test, you can tune for higher quality, 10-bit workflows, 4K contribution, multi-stream output, or backup paths. Do not start with the most complex profile. Start with the most debuggable profile.

What to monitor in Callaba after Matrox starts streaming

Once the Matrox output is active, Callaba should become the operational source of truth for the incoming feed. Do not only check whether the stream is connected. Check whether it is useful for production.

• Connection state: the Matrox caller should appear as connected to the Callaba listener.
• Bitrate: confirm that the live bitrate matches the expected encoder profile.
• Codec: confirm H.264/H.265 and profile compatibility with the next part of the workflow.
• Resolution and frame rate: confirm the received values match the production format.
• Audio: check that audio exists and is routed as expected.
• Packet loss / stability: watch for packet loss, reconnects, or jitter symptoms.
• Preview: use browser preview or multiview to confirm the picture is actually live.

Troubleshooting

Most SRT problems fall into a small number of buckets. Check them in this order.

1. No connection in Callaba

• Confirm Callaba is in Listener mode.
• Confirm Matrox is in Caller mode.
• Check the destination IP or DNS name in the Matrox profile.
• Check that the UDP port is open in the cloud firewall.
• Check that the venue network allows outbound UDP to that port.

2. Connected, but no picture

• Confirm the Matrox input has a valid SDI signal.
• Confirm the output profile is active.
• Start with H.264 before testing more specific profiles.
• Check resolution, frame rate, and audio mapping.
• Restart only the stream output first, not the whole device, so you can isolate the issue.

3. Stream drops or stutters

• Increase SRT latency.
• Lower bitrate and test again.
• Check uplink speed from the venue.
• Watch packet loss and reconnect behavior in Callaba.
• Avoid Wi-Fi for the encoder path when possible.

4. Encryption fails

• Check that encryption is enabled on both sides or disabled on both sides.
• Use the exact same passphrase on Matrox and Callaba.
• Make sure the passphrase is not too short.
• Confirm any AES/key-length option if the interface exposes it.

5. Wrong source appears

• Check stream ID.
• Do not reuse the same port for unrelated test streams unless your routing design expects it.
• Use clear names such as matrox-edge-main, matrox-edge-backup, or venue-a-camera-1.

Where this fits in a real production workflow

A Matrox encoder is usually only the first part of the chain. The more valuable workflow starts after Callaba receives the SRT stream.

This is the real reason to connect hardware encoders to a gateway. The goal is not only to receive packets. The goal is to make the hardware source part of a controlled live workflow.

Official references used for this guide

These references are useful if you want to check the device family or SRT behavior against vendor documentation:

• Matrox Monarch EDGE E4 official page
• Matrox Monarch EDGE technical specifications
• SRT protocol draft
• SRT encryption and passphrase reference

FAQ

Can Matrox Monarch EDGE send SRT to Callaba Gateway?

Yes. Monarch EDGE supports SRT and can be used as a hardware SRT contribution encoder. In a simple cloud ingest setup, Callaba Gateway listens for the incoming SRT stream and the Matrox encoder connects as the caller.

Should Matrox be Caller or Listener?

For most public cloud workflows, set Callaba as the SRT Listener and set Matrox as the SRT Caller. This keeps the open UDP port on the cloud side and usually makes firewall rules easier at the venue.

Which SRT values must match?

The UDP port, stream ID if used, encryption/passphrase if used, and latency policy must be aligned between Matrox and Callaba. A mismatch in one of these values can stop the stream from connecting or showing the expected source.

What latency should I use?

Start with 120 to 500 ms for normal internet contribution and increase it if the network is unstable. Very low latency can work on clean networks, but it gives less room for jitter and packet recovery.

Can I use SRT encryption?

Yes. Use the same passphrase and encryption setting on both sides. SRT passphrases are commonly required to be 10 to 79 UTF-8 printable characters.

Why does the stream connect but show no picture?

The transport may be connected while the media settings are still wrong. Check the video input, codec profile, resolution, audio settings, and whether the Matrox output profile is actually active.

Can I monitor the Matrox feed in a browser?

Yes. After Callaba receives the SRT stream, you can use Callaba monitoring tools, including browser preview and multiview workflows, depending on your deployment and version.

Does this guide apply to Matrox Maevex?

The SRT concept is similar, but Maevex has a different product family and management workflow. This article focuses on Monarch EDGE; Maevex deserves a separate setup article.

Final practical rule

Make the first Matrox → Callaba SRT connection boring. One output, one UDP port, one listener, one caller, no unnecessary routing. When that is stable, add encryption, stream ID, backup paths, multiview, recording, and destinations.

Try Callaba Gateway with your Matrox encoder

Create an SRT listener in Callaba, send a Monarch EDGE stream to the gateway, and monitor the feed before routing it to recording, restreaming, multiview, or player delivery.

Explore Callaba SRT server See live routing workflows