RTMP vs SRT – Which Protocol Should You Use for Live Streaming?
By StreamWithQ EngineeringUpdated 5 min read
Quick answer
Use RTMP when your connection is stable and you want maximum compatibility – every encoder supports it. Use SRT when streaming over Wi-Fi, 4G/5G, long distances or the public internet with packet loss, because SRT recovers lost packets and encrypts the stream. Viewers never see the difference; they watch HLS either way.
RTMP and SRT are ingest protocols – they carry your stream from your encoder to the streaming platform. Your viewers then receive HLS from the CDN.
Comparison
| RTMP / RTMPS | SRT | |
|---|---|---|
| Compatibility | Universal | Most modern encoders |
| Packet loss handling | TCP – stalls on loss | ARQ – retransmits lost packets |
| Bad networks (4G, Wi-Fi) | Drops and reconnects | Stays stable |
| Encryption | RTMPS (TLS) | AES-128/256 built in |
| Latency control | Fixed | Configurable buffer |
| Codecs | H.264/AAC | Codec-agnostic (H.264, HEVC) |
When to use RTMP
- A wired studio connection with plenty of upload.
- Software or services that only offer RTMP.
- Quick setups where compatibility matters most.
When to use SRT
- Outdoor events on 4G/5G bonding, remote studios, long distances.
- Contribution feeds for TV where every frame counts.
- When you need encryption end to end.
Recommended settings
- Bitrate: 1080p30 at 4.5–6 Mbps, 720p30 at 2.5–3.5 Mbps (H.264, keyframe every 2 s).
- Upload: at least 1.5× your bitrate.
- SRT latency: start at 3× your round-trip time (e.g. 300–1000 ms).
- Backup: add a second encoder to the backup ingest for automatic failover.
StreamWithQ Live Streaming accepts RTMP(S) on all plans and SRT from Live Pro.
Frequently asked questions
Yes. OBS Studio supports SRT output – choose "Custom" service and enter the srt:// URL with your stream ID and passphrase.
SRT lets you tune latency and usually matches or beats RTMP on good connections, while staying stable on bad ones. End-to-end viewer latency depends mostly on the delivery format (HLS or LL-HLS).
