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Bilbycast Bilbycast

Your First Flow

This guide walks you through creating a simple SRT-to-RTP media flow.

What is a Flow?

Section titled “What is a Flow?”

A flow in bilbycast is a single input fanning out to one or more outputs. The input receives media (e.g., from an SRT source) and each output independently delivers it to a destination.

Input (SRT) ──► broadcast channel ──► Output 1 (RTP)
                                  ──► Output 2 (UDP)
                                  ──► Output 3 (RTMP)

Slow outputs drop packets rather than causing backpressure — they never affect the input or other outputs.

Step 1: Create the Config

Section titled “Step 1: Create the Config”

Create a config.json with an SRT listener input and an RTP output:

{
  "version": 1,
  "server": {
    "listen_addr": "0.0.0.0",
    "listen_port": 8080
  },
  "monitor": {
    "listen_addr": "0.0.0.0",
    "listen_port": 9090
  },
  "flows": [
    {
      "id": "my-first-flow",
      "name": "SRT to RTP",
      "enabled": true,
      "input": {
        "type": "srt",
        "mode": "listener",
        "local_addr": "0.0.0.0:9000",
        "latency_ms": 120
      },
      "outputs": [
        {
          "type": "rtp",
          "id": "rtp-out",
          "name": "RTP Output",
          "dest_addr": "127.0.0.1:5004"
        }
      ]
    }
  ]
}

Step 2: Start the Edge

Section titled “Step 2: Start the Edge”
Terminal window
./target/release/bilbycast-edge --config config.json

The edge starts listening for SRT connections on port 9000.

Step 3: Send Media

Section titled “Step 3: Send Media”

Use any SRT-capable tool to send media to the edge:

Terminal window
# Using srt-live-transmit
srt-live-transmit udp://source:1234 srt://edge-ip:9000


# Using ffmpeg (if SRT support is compiled in)
ffmpeg -re -i input.mp4 -c copy -f mpegts srt://edge-ip:9000

Step 4: Receive the Output

Section titled “Step 4: Receive the Output”

The RTP output is sent to 127.0.0.1:5004. View it with:

Terminal window
# Using ffplay
ffplay -i rtp://127.0.0.1:5004


# Using VLC
vlc rtp://127.0.0.1:5004

Step 5: Monitor

Section titled “Step 5: Monitor”
  • REST API: http://localhost:8080/api/v1/stats
  • Monitor Dashboard: http://localhost:9090
  • Prometheus Metrics: http://localhost:9090/metrics

Adding More Outputs

Section titled “Adding More Outputs”

Add multiple outputs to the same flow. Each subscribes independently to the broadcast channel:

{
  "outputs": [
    {
      "type": "rtp",
      "id": "rtp-out",
      "name": "RTP Multicast",
      "dest_addr": "239.1.1.1:5004"
    },
    {
      "type": "srt",
      "id": "srt-out",
      "name": "SRT Forward",
      "mode": "caller",
      "remote_addr": "destination:9001",
      "latency_ms": 120
    },
    {
      "type": "rtmp",
      "id": "rtmp-out",
      "name": "YouTube Live",
      "url": "rtmp://a.rtmp.youtube.com/live2",
      "stream_key": "your-stream-key"
    }
  ]
}

Next Steps

Section titled “Next Steps”