Encoder Settings for Osprey Talon

Before you start

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:

• RTMP STREAM URL — SRT STREAM URL
• STREAM KEY — STREAM ID
• SRT input shows: PASSPHRASE

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:

1. The stream input exists and you have its credentials
2. The stream input is attached to a video
3. That video is not a draft

A new stream input is switched off. Recast switches it on only when it is attached to a live, non-draft video.

Configuration is done through the Talon's web dashboard. Find its address on your network, or from the unit's front panel where fitted.

Settings for Recast

• Great — Resolution: 1080p · FPS: 30 · Video bitrate: 5000 kbps
• Good — Resolution: 720p · FPS: 30 · Video bitrate: 3500 kbps
• Works — Resolution: 480p · FPS: 30 · Video bitrate: 1000 kbps

• Video codec — H.264 (AVC)
• Profile — Main
• Rate control — CBR
• Keyframe interval — 2 seconds
• Audio codec — AAC-LC
• Audio bitrate — 128 kbps
• Audio sample rate — 48 kHz
• Audio channels — Stereo

Use no more than 50% of your measured upload bandwidth.

The keyframe interval is set as GOP Size in the encoder settings. At 30 fps use 60; at 25 fps use 50.

SRT setup

1. Open the Talon dashboard and go to the streaming or encoder configuration.
2. Set the output type to TS over SRT.
3. Set SRT Mode to Caller. Mux listens; the Talon calls.
4. Fill in:
   • Host / Address — global-live.mux.com
   • Port — 6001
   • Stream ID — Your Recast STREAM ID
   • Latency — 500 ms

1. Enable AES-128 Encryption.
2. Paste your Recast PASSPHRASE into the passphrase field.
3. Apply, then start the stream.

Encryption must be AES-128. Mux requires a 128-bit key. If the Talon offers AES-192 or AES-256, do not use them — the handshake will fail with an error that gives no indication of the real cause.

European facilities can use eu-west.live.mux.com in place of the global host.

The complete SRT URL Recast is expecting looks like this, for reference — but enter the parts in their own fields rather than pasting the whole string:

srt://global-live.mux.com:6001?streamid=YOUR_STREAM_KEY&passphrase=YOUR_SRT_PASSPHRASE

RTMP setup

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.

1. In the dashboard, set the output type to RTMP.
2. Fill in:
   • URL / Server — rtmps://global-live.mux.com:443/app
   • Stream Name / Key — Your Recast Stream Key

1. Leave any username and password fields blank.
2. Apply, then start the stream.

If your firmware will not accept rtmps://, use rtmp://global-live.mux.com:5222/app.

Confirm you're live

1. Start the stream and check the dashboard status — it should show as connected or streaming.
2. Check the output statistics. For SRT, a stable connection with low retransmission is what you want.
3. Open the video in Recast. Allow 20 to 30 seconds — standard latency means that delay is expected.

Known quirks

Talon is a transport-stream encoder at heart. The SRT path wraps your output in MPEG-TS, which is exactly what Mux expects — hence the "TS over SRT" naming. No action needed, but it explains why the setting is not grouped with the RTMP options.

Multiple outputs share one uplink. If the Talon is feeding more than one destination, the 50% bandwidth headroom rule applies to the total.

Do not chase low latency. Recast streams run at standard latency (20–30 seconds) by design.

One protocol per stream input. A Recast stream input is created as either RTMP or SRT and cannot be switched afterwards.

Troubleshooting

Talon shows the stream as running, but Recast shows nothing

Check the stream input is attached to a video and that the video is not a draft. The Talon will report a healthy stream while Recast rejects it.

Then wait a full 30 seconds before concluding anything.

SRT connection refused or handshake failure

1. Encryption not AES-128 — Mux requires a 128-bit key
2. Stream ID empty or wrong — it must be the Recast Stream Key exactly
3. Passphrase wrong — re-copy it from Recast
4. Encryption disabled — Recast SRT inputs always carry a passphrase, so encryption must be on
5. Protocol mismatch — an SRT Recast input needs SRT
6. UDP 6001 blocked — test with the RTMP path

Stream connects then drops

Check the retransmission statistics. A rising rate means the link cannot carry the bitrate — reduce it, or raise the latency value.

You have 30 minutes to reconnect before Recast treats the stream as ended.

Viewers see stuttering

Compare the configured bitrate with what the statistics show actually leaving the unit. A gap indicates a network constraint rather than an encoder problem.

Audio missing or out of sync

Confirm AAC-LC at 48 kHz stereo, and that the correct embedded audio pair is selected. The Talon will happily encode a silent pair without warning.

Prefer embedded SDI or HDMI audio over a discrete input so both share a clock.

Getting help

Include the model and firmware version, the output type, the protocol, and a screenshot of the dashboard's stream statistics.

More detail: Recast live ingest reference

Sources

• Osprey Talon user guide
• Mux: Configuring your broadcast software for RTMP streams
• Mux: Use SRT to live stream

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