Choosing an encoder

Any encoder that sends RTMPS works with Cardinal. RTMPS is RTMP inside an encrypted (TLS) connection, the same way YouTube, Facebook and Twitch take a stream. Plain RTMP is not accepted: it would send your stream key across the internet in clear text. Encoders that support SRT can send encrypted SRT instead, with a passphrase of the stream’s own. See Encrypted ingest.

Settings every encoder needs

	1080p	4K
Resolution	1920 × 1080	3840 × 2160
Frame rate	30	30
Video	H.264, about 6,000 Kbps	H.264, about 16,000 Kbps
Upload you need	10 Mbps or more	25 Mbps or more
Keyframe interval	2 seconds	2 seconds
Audio	AAC, 48 kHz stereo, 160 Kbps	the same

The 2-second keyframe interval matters. Video is cut into segments at keyframes; a longer interval makes them uneven and lengthens the gap after a reconnect.

Set your encoder to reconnect by itself, as quickly as it allows. In OBS: Settings → Advanced → Automatically Reconnect, Retry Delay 1.

Encoders that work well

Encoder	RTMPS	Notes
OBS Studio (Windows, Mac, Linux)	version 22 and later	Free. Step-by-step guide.
vMix	version 21 and later
Wirecast	yes
Blackmagic ATEM Mini Pro and Extreme	firmware 8.6.1 and later	Update the firmware first.
Magewell Ultra Encode	yes

Most hardware encoders made in the last few years support RTMPS. Look for RTMPS or a secure option in the encoder’s streaming settings. An encoder that offers only plain RTMP can’t connect; streaming from a computer with OBS is the simplest way around it.