java调用ffmpeg获取视频时长

public static void main(String[] args) {  
  
    String result =    processFLV("E:\\video\\test.mp4");  
     
     
    PatternCompiler compiler =new Perl5Compiler();  
    try {  
        String regexDuration ="Duration: (.*?), start: (.*?), bitrate: (\\d*) kb\\/s";  
        String regexVideo ="Video: (.*?), (.*?), (.*?)[,\\s]";  
        String regexAudio ="Audio: (\\w*), (\\d*) Hz";  
     
        Pattern patternDuration = compiler.compile(regexDuration,Perl5Compiler.CASE_INSENSITIVE_MASK);  
        PatternMatcher matcherDuration = new Perl5Matcher();  
        if(matcherDuration.contains(result, patternDuration)){  
            MatchResult re = matcherDuration.getMatch();  
  
            System.out.println("提取出播放时间  ===" +re.group(1));  
            System.out.println("开始时间        =====" +re.group(2));  
            System.out.println("bitrate 码率 单位 kb==" +re.group(3));  
        }  
         
        Pattern patternVideo = compiler.compile(regexVideo,Perl5Compiler.CASE_INSENSITIVE_MASK);  
        PatternMatcher matcherVideo = new Perl5Matcher();  
         
        if(matcherVideo.contains(result, patternVideo)){  
            MatchResult re = matcherVideo.getMatch();  
            System.out.println("编码格式  ===" +re.group(1));  
            System.out.println("视频格式 ===" +re.group(2));  
            System.out.println(" 分辨率  == =" +re.group(3));  
        }  
         
        Pattern patternAudio = compiler.compile(regexAudio,Perl5Compiler.CASE_INSENSITIVE_MASK);  
        PatternMatcher matcherAudio = new Perl5Matcher();  
         
        if(matcherAudio.contains(result, patternAudio)){  
            MatchResult re = matcherAudio.getMatch();  
            System.out.println("音频编码             ===" +re.group(1));  
            System.out.println("音频采样频率  ===" +re.group(2));  
        }  
  
    } catch (MalformedPatternException e) {  
        e.printStackTrace();  
    }  
  
    }  
     
  
//  ffmpeg能解析的格式：（asx，asf，mpg，wmv，3gp，mp4，mov，avi，flv等）  
    private static String processFLV(String inputPath) {  
/* 
      if (!checkfile(inputPath)){ 
          _log.warn(inputPath+" is not file"); 
          return false; 
         } 
*/  
        List<String> commend=new java.util.ArrayList<String>();  
         
//        commend.add("D:\\ffmpeg-20140727-git-ad91bf8-win32-static\\bin\\ffmpeg ");//可以设置环境变量从而省去这行  
       commend.add("ffmpeg");  
        commend.add("-i");  
        commend.add(inputPath);  
        
        try {  
  
            ProcessBuilder builder = new ProcessBuilder();  
            builder.command(commend);  
            builder.redirectErrorStream(true);  
            Process p= builder.start();  
  
           //1. start  
            BufferedReader buf = null; // 保存ffmpeg的输出结果流  
            String line = null;  
          //read the standard output  
  
            buf = new BufferedReader(new InputStreamReader(p.getInputStream()));  
             
            StringBuffer sb= new StringBuffer();  
            while ((line = buf.readLine()) != null) {  
             System.out.println(line);  
             sb.append(line);  
             continue;  
                 }  
            int ret = p.waitFor();//这里线程阻塞，将等待外部转换进程运行成功运行结束后，才往下执行  
            //1. end  
            return sb.toString();  
        } catch (Exception e) {  
//            System.out.println(e);  
            return null;  
        }  
    }