Playback Feature

Overview

The playback feature provides powerful playback capabilities for audio and video streams, supporting multiple output formats including MP4, FLV, and fragmented MP4 (fMP4). The system supports real-time playback, on-demand playback, multi-segment merged playback and other playback modes, providing flexible playback controls and rich player integration options.

System Architecture

Key Features

Playback Modes

• Real-time Playback: Low-latency real-time stream playback
• On-demand Playback: Play content from specified time periods
• Multi-segment Merge: Automatically merge multiple recording segments
• Loop Playback: Continuous loop playback mode

Format Support

• MP4: Standard container format, supports complete file download
• fMP4: Fragmented format, supports streaming and real-time playback
• FLV: Traditional format, good compatibility
• WebSocket Stream: Low-latency real-time transmission

Playback Controls

• Time Range Playback: Precise time period playback
• Seek and Speed Control: Flexible playback controls
• Pause and Resume: Real-time playback control
• Progress Adjustment: Jump to any time point

Advanced Features

• Time Range Playback: Precise time period playback
• Multi-segment Auto Merge: Seamlessly connect recording segments
• Seek and Speed Control: Flexible playback control
• Loop Playback: Continuous loop mode

Playback Workflow

participant API as Playback API
participant Engine as Playback Engine
participant Storage as Storage System
participant DB as Database

Player->>API: Request Playback Stream
API->>DB: Query Recording Files
DB-->>API: Return File Info
API->>Engine: Start Playback Task
Engine->>Storage: Read Recording File
Engine-->>Player: Push Audio/Video Stream

Player->>API: Playback Control (Pause/Seek)
API->>Engine: Execute Control Command
Engine->>Storage: Adjust Read Position
Engine-->>Player: Continue Stream Push

## Configuration Examples

### Playback Pull Configuration

```yaml
mp4:
  onsub:
    pull:
      ^vod/(.+)$: live/$1  # vod/camera1 → live/camera1
  pull:
    live/movie: /path/to/movie.mp4
    delayclosetimeout: 3s

Advanced Playback Configuration

mp4:
  onsub:
    pull:
      # Basic playback matching
      ^vod/(.+)$: live/$1
      # Multi-level directory matching
      ^archive/(\d{4})/(\d{2})/(\d{2})/(.+)$: live/$4?start=$1-$2-$3T00:00:00
      # Independent playback progress
      ^vod(\d)/(.+)$: live/$2

Key Parameter Description:

• delayclosetimeout: Delay close time when no subscribers
• Regular expressions support capture groups, referenced with $1, $2
• Time parameters support ISO 8601 format and Unix timestamps

Playback Management API

Query API Endpoints

Function	Method	Path	Description
Recording Files	GET	/mp4/api/list/{streamPath}	Get recording file list
Recording Catalog	GET	/mp4/api/catalog	Get recording directory structure

Stream Control API

Function	Method	Path	Description
Pause Playback	POST	/api/stream/pause/{streamPath}	Pause stream playback
Resume Playback	POST	/api/stream/resume/{streamPath}	Resume stream playback
Set Speed	POST	/api/stream/speed/{streamPath}	Set playback speed
Time Seek	POST	/api/stream/seek/{streamPath}	Seek to specific time

API Usage Examples

// Get recording list
const recordings = await fetch('/mp4/api/list/live/camera1').then(r => r.json());

// Get recording catalog
const catalog = await fetch('/mp4/api/catalog').then(r => r.json());

// Playback control
await fetch('/api/stream/pause/live/camera1', { method: 'POST' });
await fetch('/api/stream/speed/live/camera1', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ speed: 2.0 })
});

// Time seek
await fetch('/api/stream/seek/live/camera1', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ timeStamp: Math.floor(Date.now() / 1000) })
});

Playback URL Formats

Basic playback:http://localhost:8080/flv/live/camera1.flv?start=2024-01-01T12:00:00

Time range playback:http://localhost:8080/mp4/live/camera1.mp4?start=2024-01-01T12:00:00&end=2024-01-01T13:00:00

WebSocket real-time playback:ws://localhost:8080/mp4/live/camera1.mp4

Frontend Player Integration

Supported Playback Methods

Common Player Integration

Player Type	Use Case	Key Features
HTML5 Video	Basic playback	Simple to use, good compatibility
Video.js	Professional playback	Feature-rich, many plugins
HLS.js	Streaming playback	Adaptive bitrate, low latency
Custom MSE	Real-time playback	Precise control, real-time performance

Basic Integration Example

<!-- Basic MP4 playbook -->
<video controls>
  <source src="/mp4/download/live/camera1.mp4" type="video/mp4">
</video>

<!-- fMP4 streaming playbook -->
<video id="player"></video>
<script>
const video = document.getElementById('player');
const ws = new WebSocket('ws://localhost:8080/mp4/live/camera1.mp4');
// Use MSE for streaming playbook
</script>

Performance Optimization Recommendations

System Optimization

Key Parameter Configuration

Parameter	Recommended Value	Description
fragment	10-30s	Balance file size and performance
buffer_size	10-30MB	Adjust based on network conditions
max_connections	100-500	Set based on server performance
cleanup_interval	24h	Regular cleanup of expired files

Troubleshooting

Common Problem Resolution Flow

Monitoring Metrics

• Playback Status: Real-time monitoring of playback task status
• File Reading: Disk IO and read performance
• Network Bandwidth: Download bandwidth usage
• Playback Quality: Latency, frame drop rate, error rate
• User Experience: Buffer time, playback success rate

Summary

Monibuca's playback feature provides a complete video playback solution, supporting multiple formats and playback methods. Through proper configuration and optimization, high-quality, low-latency audio and video playback services can be achieved. Key advantages include:

• Flexible Playback Modes: Support for real-time, on-demand, and multi-segment merged playback
• Multi-format Support: MP4, fMP4, FLV and other formats
• Rich Playback Controls: Pause, seek, speed control and other functions
• Easy Integration: Support for various mainstream players
• High Performance: Optimized storage reading and transmission mechanisms