Transcoding

Transcoding is an important feature in Monibuca that allows converting video streams to different encoding formats and resolutions.

Feature Highlights

• Supports multiple encoding formats
• Supports multiple resolutions
• Supports bitrate control
• Supports framerate control
• Supports hardware acceleration

Environment Requirements

The transcoding plugin depends on the FFmpeg transcoding engine. Before using, please ensure:

1. FFmpeg is properly installed in the system
2. FFmpeg's execution path is added to the system's PATH environment variable
3. You can verify the installation by running ffmpeg -version directly in the command line

Note: If FFmpeg is not properly configured, the transcoding feature will not work. The method to configure PATH environment variables varies by operating system. Please refer to the relevant system documentation.

Usage Examples

Configuring Transcoding Rules

Here's an example of transcoding configuration in YAML format:

transcode:
  onpub:
    transform:
      ^live.+:  # Use regular expression to match stream names
        input:
          mode: rtsp  # Input mode
        output:
          - target: rtmp://localhost/trans/$0/small  # Output target, $0 represents the matched stream name
            conf: -loglevel debug -c:a aac -c:v h264 -vf scale=320:240  # FFmpeg configuration parameters

This configuration will match all streams starting with "live" and create a transcoded output with resolution 320x240.

Custom Transcoding Configuration

You can also set multiple different transcoding configurations for specific streams:

transcode:
  transform:
    camera1:  # Specific stream name
      input:
        mode: rtsp
      output:
        - target: rtmp://localhost/trans/camera1/hd
          conf: -c:a aac -c:v h264 -vf scale=1280:720 -b:v 2000k -b:a 128k
        - target: rtmp://localhost/trans/camera1/sd
          conf: -c:a aac -c:v h264 -vf scale=640:360 -b:v 800k -b:a 64k

Adding Transcoding Rules via API

POST /api/v1/transcode/rules
Content-Type: application/json

{
    "streamPath": "camera1",
    "transform": {
        "input": {
            "mode": "rtsp"
        },
        "output": [
            {
                "target": "rtmp://localhost/trans/camera1/hd",
                "conf": "-c:a aac -c:v h264 -vf scale=1280:720 -b:v 2000k -b:a 128k"
            }
        ]
    }
}

Important Notes

1. Ensure sufficient hardware resources
2. Set reasonable transcoding parameters
3. Pay attention to transcoding latency
4. Monitor system load
5. Regularly check transcoding quality

Common Issues

1. Transcoding Failure

   • Check hardware status
   • Verify transcoding parameters
   • Confirm input stream is normal

2. Transcoding Latency

   • Optimize transcoding parameters
   • Use hardware acceleration
   • Adjust buffer size

3. Transcoding Quality

   • Check bitrate settings
   • Verify resolution
   • Confirm encoding parameters

Best Practices

1. Hardware Acceleration

   • Use GPU acceleration when available
   • Monitor GPU utilization
   • Balance quality and performance

2. Resource Management

   • Monitor CPU usage
   • Track memory consumption
   • Implement load balancing
   • Set resource limits

3. Quality Control

   • Regular quality checks
   • Monitor bitrate stability
   • Verify output consistency
   • Implement quality metrics

Advanced Configuration

1. Input Configuration

   input:
     mode: rtsp
     buffer: 2s
     reconnect: true
     reconnect_interval: 5s

2. Output Configuration

   output:
     - target: rtmp://localhost/trans/$0/hd
       conf: |
         -c:a aac -b:a 128k
         -c:v h264 -preset medium
         -b:v 2000k -maxrate 2500k
         -bufsize 4000k
         -vf scale=1280:720
         -r 30

3. Error Handling

   error:
     retry: true
     max_retries: 3
     retry_interval: 5s
     on_failure: log

Monitoring and Management

1. Status Monitoring

   GET /api/v1/transcode/status/{streamPath}

2. Performance Metrics

   GET /api/v1/transcode/metrics/{streamPath}

3. Resource Usage

   GET /api/v1/transcode/resources