To stream your MP4 video file to Owncast using FFmpeg, follow these steps:

1. Locate Your Owncast RTMP Credentials

• In your Owncast admin dashboard (http://your-server:8080/admin), go to Configuration → Stream Keys.
• Copy the Stream URL (e.g., rtmp://your-server/live) and Stream Key (e.g., abc123-secret-key).

2. Basic FFmpeg Command

fffmpeg -re -stream_loop -1 -i video.mp4 \
       -map 0:v -map 0:a \
       -c:v libx264 -preset veryfast -b:v 2500k -maxrate 2500k -bufsize 5000k -g 60 -pix_fmt yuv420p \
       -c:a aac -b:a 128k -ar 44100 \
       -f flv 'rtmp://localhost:1935/live/key'

Explanation of Flags:

• -re: Read input at native frame rate (avoids streaming too fast).
• -stream_loop -1: Loop the video infinitely (remove this to stream once).
• -c:v libx264: Use H.264 video codec.
• -preset veryfast: Balances speed and compression efficiency.
• -b:v 2500k: Video bitrate (adjust based on your video resolution).
• -g 60: Keyframe interval (2 seconds for 30fps; critical for seeking).
• -pix_fmt yuv420p: Ensures compatibility with players.
• -c:a aac: Use AAC audio codec.
• -f flv: Output format for RTMP.

3. Advanced Options

a. Hardware Acceleration (if supported):

ffmpeg -hwaccel cuda -re -i input.mp4 -c:v h264_nvenc ... (rest of the command)

Replace cuda/h264_nvenc with your GPU's acceleration method (e.g., vaapi for Intel).

b. No Looping (stream once):

Remove -stream_loop -1.

c. Custom Resolution (e.g., 720p):

Add -vf "scale=1280:720" before -c:v libx264.

4. Verify the Stream

1. Run the FFmpeg command in your terminal.
2. Visit your Owncast instance at http://your-server:8080 to watch the stream.

5. Troubleshooting

• Codec Errors: Ensure your FFmpeg supports libx264 and aac (install with ffmpeg -codecs | grep -E 'libx264|aac').
• Connection Issues: Check firewall rules (RTMP typically uses port 1935).
• Quality Adjustments: Lower -b:v if bandwidth is limited (e.g., 1000k for 720p).