RTMP to SRT Migration: Complete Step-by-Step Guide

#srt #rtmp #streaming #migration

Why Migrate from RTMP to SRT?

RTMP was designed for a different internet. SRT was built for unreliable networks with UDP transport, selective retransmission (ARQ), and built-in AES encryption.

What you gain:

Built-in encryption: AES-128 or AES-256, native to the protocol
Lower latency: UDP avoids TCP head-of-line blocking
Better error recovery: tolerates up to 30% packet loss
Real-time diagnostics: RTT, jitter, packet loss, bandwidth estimation
Bonding: SRTLA aggregates multiple connections

Before You Start

Inventory Your RTMP Endpoints

List every ingest point and output destination.

Check Encoder SRT Support

Encoder	SRT Support
OBS Studio	Yes (v27+)
vMix	Yes
Wirecast	Yes (v14+)
FFmpeg	Yes
BELABOX	Yes + SRTLA
Older hardware	Often no

Encoders without SRT need protocol conversion at the gateway.

Check Your Network

SRT uses UDP. Most corporate firewalls block it by default:

# Server side
nc -u -l 9000
# Encoder side
echo "test" | nc -u your-server.com 9000

Step 1: Set Up Your SRT Gateway

Use a gateway as the central conversion point. Migrate one encoder at a time.

Create SRT Listener on port 9000
Set latency based on network path (60ms LAN to 3000ms cellular)
Enable AES-256 encryption

Step 2: Configure OBS for SRT

srt://your-server:9000?latency=500000&passphrase=YourPassphrase&pbkeylen=32

OBS uses microseconds: 500ms = 500000.

Output settings: CBR, 6000 Kbps, keyframe 2s, zerolatency tune.

Step 3: Configure FFmpeg

ffmpeg -i input.mp4 \
  -c:v libx264 -b:v 6000k -g 60 \
  -c:a aac -b:a 128k \
  -f mpegts \
  "srt://your-server:9000?mode=caller&latency=500000&passphrase=YourPassphrase&pbkeylen=32"

Key: -f mpegts because SRT uses MPEG-TS, not FLV.

Step 4: Keep RTMP Outputs Where Needed

YouTube, Twitch, Facebook still require RTMP. Your gateway converts:

Encoder -> SRT (encrypted) -> Gateway -> RTMP -> YouTube/Twitch
                                       -> SRT  -> Production
                                       -> SRT  -> Recording

Step 5: Set Up Failover

With SRT real-time health metrics, detect degradation before full failure:

Packet loss: switch at >5% sustained for 2 seconds
Timeout: switch after 500ms of no data
Bitrate floor: switch if below 50% expected

Validation Checklist

[ ] SRT connection establishes
[ ] Encryption active (AES-256)
[ ] No unrecovered packet loss
[ ] Video plays cleanly on all outputs
[ ] Audio in sync
[ ] Failover tested
[ ] 4-hour duration test passed

Migration Timeline

Week	Action
1	Audit RTMP setup
2	Deploy SRT gateway, test
3	Migrate first encoder, run parallel
4	Validate, test failover
5	Migrate remaining encoders
6	Decommission RTMP ingest points