使用JMF播放MPEG等格式视频抛出CannotRealizeException问题求助

问题描述 #

我正通过相关教程学习使用JMF播放视频，运行时抛出无法实现播放器的错误，选中官方支持格式的视频文件后提示Could not realize Media PLayer，试过mpg、mpeg、au等适配格式都无法正常播放，问题现象如下：

报错信息 #

Unable to handle format: MPEG, 1280x720, FrameRate=23.9, Length=1382400 
Failed to realize: com.sun.media.PlaybackEngine@659a969b 
Error: Unable to realize com.sun.media.PlaybackEngine@659a969b 
javax.media.CannotRealizeException at 
javax.media.Manager.blockingCall(Manager.java:2005) at 
javax.media.Manager.createRealizedPlayer(Manager.java:528) at 
com.mycompany.mavenproject3.MediaPanel.<init>(MediaPanel.java:33) at 
com.mycompany.mavenproject3.MediaTest.main(MediaTest.java:47) 
Could not realize media player

相关代码 #

MediaPanel.java #

import java.awt.BorderLayout;
import java.awt.Component;
import java.io.IOException;
import java.net.URL;
import javax.media.CannotRealizeException;
import javax.media.Manager;
import javax.media.NoPlayerException;
import javax.media.Player;
import javax.swing.JPanel;

public class MediaPanel extends JPanel
{
 public MediaPanel( URL mediaURL )
{
 setLayout( new BorderLayout() ); // use a BorderLayout

 // Use lightweight components for Swing compatibility 
 Manager.setHint( Manager.LIGHTWEIGHT_RENDERER, true );

  try
 {
 // create a player to play the media specified in the URL 
 Player mediaPlayer = Manager.createRealizedPlayer( mediaURL );

 // get the components for the video and the playback controls 
 Component video = mediaPlayer.getVisualComponent(); 
 Component controls = mediaPlayer.getControlPanelComponent(); 

 if ( video != null ){
 add( video, BorderLayout.CENTER ); 
 }

 if ( controls != null ){
 add( controls, BorderLayout.SOUTH ); 
 }

 mediaPlayer.start(); // start playing the media clip
 } // end try
 catch ( NoPlayerException noPlayerException )
 {
 System.err.println( "No media player found" );
 } // end catch
 catch ( CannotRealizeException cannotRealizeException )
 {
 System.err.println( "Could not realize media player" );
 } // end catch
 catch ( IOException iOException )
 {
 System.err.println( "Error reading from the source" );
 } // end catch
 } // end MediaPanel constructor
 } // end class MediaPanel

MediaTest.java #

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import javax.swing.JFileChooser;
import javax.swing.JFrame;

public class MediaTest{

public static void main( String args[] )
{

JFileChooser fileChooser = new JFileChooser();


int result = fileChooser.showOpenDialog( null );

if ( result == JFileChooser.APPROVE_OPTION ) // user chose a file
{
URL mediaURL = null;

try
{

mediaURL = fileChooser.getSelectedFile().toURL();
} 
catch ( MalformedURLException malformedURLException )
{
System.err.println( "Could not create URL for the file" );
} 

if ( mediaURL != null ) 
{
JFrame mediaTest = new JFrame( "Media Tester" );
mediaTest.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );

MediaPanel mediaPanel = new MediaPanel( mediaURL );
mediaTest.add( mediaPanel );

mediaTest.setSize( 300, 300 );
mediaTest.setVisible( true );
} 

} 
} 
}

pom.xml #

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.mycompany</groupId>
    <artifactId>mavenproject3</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <dependencies>
        <dependency>
            <groupId>javax.media</groupId>
            <artifactId>jmf</artifactId>
            <version>2.1.1e</version>
        </dependency>
        <dependency>
            <groupId>com.conviva.sdk</groupId>
            <artifactId>conviva-mediaplayer-sdk</artifactId>
            <version>2.145.0</version>
            <type>aar</type>
        </dependency>
    </dependencies>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>16</maven.compiler.source>
        <maven.compiler.target>16</maven.compiler.target>
    </properties>
</project>

解决方案 #

• 替换JMF依赖包：公共maven仓库中的jmf 2.1.1e是精简版，缺少原生解码组件和格式支持库，需要获取完整的JMF安装包，提取jmf.jar、sound.jar、mediaplayer.jar三个核心包，手动导入到本地maven仓库替换现有依赖。
• 切换兼容JDK版本：JMF最后更新为2004年，仅支持JDK1.4到JDK8版本，你当前使用的JDK16无法兼容，将pom中的maven.compiler.source和maven.compiler.target修改为1.8，本地运行环境同步切换为JDK8。
• 调整视频参数：JMF支持的MPEG1/2视频分辨率最高为720x480，最高帧率30fps，你使用的1280x720规格超出支持范围，将测试视频转码为低分辨率MPEG1格式后再测试。
• 修改Player初始化逻辑：不要直接调用createRealizedPlayer同步初始化，改为分步异步加载避免资源锁问题，修改后的核心代码如下：

import javax.media.ControllerEvent;
import javax.media.ControllerListener;
import javax.media.PrefetchCompleteEvent;
import javax.media.RealizeCompleteEvent;

// 替换原有Player初始化逻辑
Player mediaPlayer = Manager.createPlayer(mediaURL);
mediaPlayer.addControllerListener(new ControllerListener() {
    @Override
    public void controllerUpdate(ControllerEvent event) {
        if (event instanceof RealizeCompleteEvent) {
            mediaPlayer.prefetch();
        } else if (event instanceof PrefetchCompleteEvent) {
            Component video = mediaPlayer.getVisualComponent();
            Component controls = mediaPlayer.getControlPanelComponent();
            if (video != null) add(video, BorderLayout.CENTER);
            if (controls != null) add(controls, BorderLayout.SOUTH);
            revalidate();
            repaint();
            mediaPlayer.start();
        }
    }
});
mediaPlayer.realize();

• 移除无效依赖：pom中的conviva-mediaplayer-sdk是安卓端AAR包，和桌面端JMF项目完全不兼容，直接删除该依赖避免类冲突。

内容的提问来源于stack exchange，提问作者coder_01