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.
SRT support arrived in the ATEM line at version 9.5 and is documented as requiring 9.6 on both the software and the switcher's own firmware. Updating one without the other is a common mistake: ATEM Software Control updates the switcher firmware when you connect, so run the updater and let it finish.
For RTMP, any recent version works.
Use no more than 50% of your measured upload bandwidth.
The ATEM Mini does not do true constant bitrate. Its streaming engine is variable-bitrate, and there is no setting to change that. This is fine for Recast — but because the peaks are higher than the average, leave more headroom than usual. Treat a 5000 kbps profile as needing 12 Mbps of real upload rather than 10.
Most encoder settings are not directly exposed. You choose a streaming quality profile and the hardware picks the rest.
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.
ATEM Software Control reads its list of streaming platforms from a file called Streaming.xml. Adding Recast means editing that file.
The file lives at:
/Library/Application Support/Blackmagic Design/Switchers/Streaming.xmlC:\Program Files (x86)\Blackmagic Design\Blackmagic ATEM Switchers\ATEM Software Control\Streaming.xmlDo this before the day. It needs administrator rights and an application restart.
Streaming.xml somewhere safe before you touch it.<service>
<name>Recast</name>
<servers>
<server>
<name>Primary</name>
<url>rtmps://global-live.mux.com:443/app</url>
</server>
</servers>
<profiles>
<profile>
<name>Streaming High</name>
<config resolution="1080p" fps="30">
<bitrate>5000000</bitrate>
<audio-bitrate>128000</audio-bitrate>
</config>
</profile>
<profile>
<name>Streaming Medium</name>
<config resolution="720p" fps="30">
<bitrate>3500000</bitrate>
<audio-bitrate>128000</audio-bitrate>
</config>
</profile>
</profiles>
</service>Match the structure and indentation of the service blocks already in your file — the exact schema varies between ATEM versions, and copying the shape of a working entry is more reliable than copying this one verbatim. Note that bitrates here are in bits per second, so 5000 kbps is 5000000.Streaming.xml in exactly that folder; renaming it breaks the list entirely.If you have a Web Presenter rather than an ATEM Mini, configure it through Blackmagic Web Presenter Setup, which accepts a custom RTMP server and key directly without the XML step.
Requires ATEM 9.6 or Web Presenter 3.4, as above.
Blackmagic's SRT implementation is configured in the Stream palette, or in Web Presenter Setup, with these values:
Callerglobal-live.mux.com6001500 msKey length must be 128-bit. Mux requires it.
If your version presents SRT as a single URL field rather than separate fields, use:
srt://global-live.mux.com:6001?streamid=YOUR_STREAM_KEY&passphrase=YOUR_SRT_PASSPHRASE&pbkeylen=16
If there is no SRT option at all, your firmware predates it. Update, or use RTMP.
Editing Streaming.xml is a per-computer job. The file lives on the computer running ATEM Software Control, not on the switcher. Move to a different laptop and you must do it again. Keep your edited file somewhere you can find it, and carry it to the venue with the kit.
Software updates overwrite the file. Updating ATEM Software Control usually replaces Streaming.xml and your Recast entry disappears. This is a nasty surprise on show day. Keep your edited copy and reapply it after every update.
No true CBR. As above — leave extra bandwidth headroom.
Keep the software and firmware in step. ATEM Software Control updates the switcher's firmware on connection. If SRT options are missing after an update, connect the switcher and let the updater run.
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.
The Streaming.xml edit did not take. In order:
Streaming.xml, in the original folder?.txt extension? Windows hides this by default.Check the stream input is attached to a video and that the video is not a draft. The ATEM will show a healthy stream while Recast rejects it.
Then wait a full 30 seconds before concluding anything.
<url> elementUsually bandwidth, and the variable bitrate makes the ATEM more sensitive to a marginal connection than other encoders. Drop to the next quality profile down rather than adjusting anything else.
Then use ethernet rather than sharing a phone's connection, which is a common ATEM Mini setup and a common cause of dropouts.
You have 30 minutes to reconnect before Recast treats the stream as ended.
Drop a quality profile. Because you cannot fine-tune the bitrate, the profile list is your only lever — and the next one down is usually the right answer.
Check the audio mixer in ATEM Software Control: the relevant input may be muted or set to follow the programme source rather than being on. This is by far the most common cause of silence on an ATEM.
For sync, use the audio delay control in the mixer. Prefer audio embedded in the HDMI or SDI signal over the separate 3.5 mm input, so both share a clock.
Include the model, the ATEM Software Control version and switcher firmware version, the quality profile in use, the protocol, and your measured upload speed. If Recast is missing from the platform list, attach your Streaming.xml.
More detail: Recast live ingest reference
