如何才能获取到Process

public class ConvertVideo {

private static String INPUT_PATH;  
    private static String OUTPUT_PATH;  
    private static String PROJECT_PATH;  
    private static HashMap<String, String> fileType;  
      
    static 
    {  
        fileType = new HashMap<String, String>();  
        fileType.put("avi", "true");  
        fileType.put("mpg", "true");  
        fileType.put("wmv", "true");  
        fileType.put("3gp", "true");  
        fileType.put("mov", "true");  
        fileType.put("mp4", "true");  
        fileType.put("asf", "true");  
        fileType.put("asx", "true");  
       fileType.put("flv", "true");  
    }  
      
    public static void convertToFLV(String projectPath, String inputFile, String outputFile)  
    {  
        INPUT_PATH = inputFile;  
        OUTPUT_PATH = outputFile;  
        PROJECT_PATH = projectPath;  
        if (checkContentType())  
            processFLV();// 直接将文件转为flv文件  
    }  
 
    private static boolean checkContentType()  
    {  
        String type = INPUT_PATH.substring(INPUT_PATH.lastIndexOf(".") + 1, INPUT_PATH.length()).toLowerCase();  
        // ffmpeg能解析的格式：（asx，asf，mpg，wmv，3gp，mp4，mov，avi，flv等）  
        return "true".equals(fileType.get(type));  
    }  
 
    private static void processFLV()  
   {  
        if (new File(INPUT_PATH).isFile())  
        {  
            try 
            {  
                String cmd = "cmd /c start F:\\project\\abc\\ffmpeg.bat \"" + PROJECT_PATH + "\" \"" + INPUT_PATH + "\" \"" + OUTPUT_PATH +"\"";  
                System.out.println(cmd);
                Process process = Runtime.getRuntime().exec(cmd);
                InputStream is = process.getInputStream();
                BufferedInputStream bis = new BufferedInputStream(is);
                System.out.println(bis);
                int data;
                while((data=bis.read())!=-1){
                System.out.println(data);
                }
                if(data==-1){
                System.out.println("data==null");
                }
            }  
            catch (Exception e)  
            {  
               e.printStackTrace();  
            }  
        }  
    } 
    public static void main(String[] args)  
    {  
        ConvertVideo.convertToFLV("F:\\project\\abc" ,"c:\\3.mpg", "f:\\03.mpg");  
    }

}

用ffmpeg为视频添加logo，但是始终获取不到process的值？转出来的文件确定是有logo的。