Recently, a project required backend video recording. Following a friend’s recommendation, I used the zlmediakit service, which solved the video recording problem.

1. zlmediakit Installation and Configuration

Deploy using docker-compose, mapping the conf and media directories for easy configuration file modification and persistence of recording files.

docker-compose.yml configuration (with streaming recording enabled):

version: "3.9"

services:
  zlmediakit:
    image: registry.cn-beijing.aliyuncs.com/wuhm/zlmediakit:master
    container_name: zlmediakit
    privileged: true
    command: /opt/media/bin/MediaServer -c /opt/media/conf/config.ini
    ports:
      - "11935:1935"
      - "180:80"
      - "1554:554"
      - "9009:9000/udp"
      - "10000:10000/tcp"
      - "10000:10000/udp"
      - "30000-30500:30000-30500/tcp"
      - "30000-30500:30000-30500/udp"
    volumes:
      - ./conf/config.ini:/opt/media/conf/config.ini
      - ./media:/opt/media/bin/www
    environment:
      TZ: "Asia/Shanghai"
    restart: "on-failure:3"

The conf directory contains only one config.ini configuration file. The most important configuration is the secret for API calls.

Files can be accessed directly in the browser:

2. Client Streaming

2.1 Add Dependency

I’m using Java, and there’s a ready-made package available:

<!-- FFmpeg Java Wrapper -->
<dependency>
    <groupId>org.bytedeco</groupId>
    <artifactId>javacv-platform</artifactId>
    <version>1.5.8</version>
</dependency>

2.2 Start Streaming

This example streams using an unencrypted FLV URL to RTMP using JavaCV. The code includes configuration for FFmpeg grabber and recorder, handling video and audio codecs, frame rate control, and continuous streaming with proper resource management.

3. Recording

3.1 Start ZLM Recording

Use the ZLM API to start recording with custom path and segment duration:

public void startZLMRecordingViaAPI(String zlmHost, String zlmApiPort, String secret,
                                   String appName, String streamId) {
    String apiUrl = String.format("http://%s:%s/index/api/startRecord", zlmHost, zlmApiPort);
    Map<String, Object> params = new HashMap<>();
    params.put("secret", secret);
    params.put("type", 0); // 0=hls,1=mp4
    params.put("vhost", "__defaultVhost__");
    params.put("app", appName);
    params.put("stream", streamId);
    params.put("max_second", 30); // 30 second segments
    // Send HTTP request...
}

3.2 Stop ZLM Recording

public void stopZLMRecordingViaAPI(String zlmHost, String zlmApiPort, String secret,
                                  String appName, String streamId) {
    // Similar to start, with /stopRecord endpoint
}

3.3 Get Recording Files

Recording files require some time to be generated. Scan the directory to find the generated MP4 files.

With the video files, you can store them in services like MinIO.