Issues in executing FFmpeg command in Java code in Linux

Question

I have problems executing this ffmpeg command in my java code:

ffmpeg -i sample.mp4 -i ad.mp4 -filter_complex "[0:v]trim=0:15,setpts=PTS-STARTPTS[v0]; [1:v]trim=0:5,setpts=PTS-STARTPTS[v1]; [0:v]trim=20:30,setpts=PTS-STARTPTS[v2]; [v0][v1][v2]concat=n=3:v=1:a=0[out]" -map "[out]" output.mp4

I used the getRuntime() method below, but that doesn't work for me. Even if I simply remove the ", still it doesn't work. When I simply copy-paste the equivalent string in terminal, it works.

String c1=" -i "+dir+"sample.mp4 "+"-i "+dir+"ad.mp4 -fi‌​lter_complex [0:v]‌​trim=0:15,setpts=PTS‌​-STARTPTS[v0]; [1:v]trim=0:5,setpts=PTS-STARTPTS[v1]; [0:v]trim=20:30,setpts=PTS-STARTPTS[v2]; [v0][v1][v2]concat=n=3:v=1:a=0[out] -map [out] "+dir+"output.‌​mp4";
RunCommand("ffmpeg"+c1);

Using this method:

private static void RunCommand(String command) throws InterruptedException {
    try {
        // Execute command
        Process proc = Runtime.getRuntime().exec(command);
        System.out.println(proc.exitValue());

        // Get output stream to write from it
        // Read the output

        BufferedReader reader =  
                new BufferedReader(new InputStreamReader(proc.getInputStream()));
        String line = "";
        while((line = reader.readLine()) != null) {
            System.out.print(line + "\n");
            //              System.out.println(ads.get(0));
        }
        proc.waitFor();  

    } catch (IOException e) {
    }
}

This one doesn't work also, and printing the exit value shows this:

Exception in thread "main" java.lang.IllegalThreadStateException: process hasn't exited
    at java.lang.UNIXProcess.exitValue(UNIXProcess.java:423)
    at parser.Parser.RunCommand(Parser.java:106)
    at parser.Parser.commandGenerator2(Parser.java:79)
    at parser.Parser.main(Parser.java:44)

If I move the proc.waitFor(); before printing the exit value, it is 1.

What is the problem? Why it doesn't run in Java code?

Answer 1

There is some issue on your code, First, use thread to stream in and err of inner process to the console

Create a pipe stream class like :

class PipeStream extends Thread {
    InputStream is;
    OutputStream os;

    public PipeStream(InputStream is, OutputStream os) {
        this.is = is;
        this.os = os;
    }

    public void run() {
        byte[] buffer=new byte[1024];
        int len;
        try {
            while ((len=is.read(buffer))>=0){
                os.write(buffer,0,len);
            }
        } catch (IOException e) {
            e.printStackTrace();  
        }
    }
}

Then adapt the runtime part to:

System.out.println("Launching command: "+command);
ProcessBuilder pb = new ProcessBuilder("/bin/sh", "-c", command);
Process proc=pb.start();

PipeStream out=new PipeStream(proc.getInputStream(), System.out);
PipeStream err=new PipeStream(proc.getErrorStream(), System.err);
out.start();
err.start();

proc.waitFor();
System.out.println("Exit value is: "+proc.exitValue());

It will show the command that will be run, the logs and potentially the error.

You will be able to copy paste the command to check on a terminal what is going on if needed.

EDIT: This is very funny. You code was missing some escape char AND there is not visible char in your code. I saw them when I copy paste the line of code. Copy paste the following line in your code, it will remove the error :

String command="ffmpeg -i "+dir+"sample.mp4 -i "+dir+"ad.mp4 -filter_complex '[0:v]trim=0:15,setpts=PTS-STARTPTS[v0]; [1:v]trim=0:5,setpts=PTS-STARTPTS[v1]; [0:v]trim=20:30,setpts=PTS-STARTPTS[v2]; [v0][v1][v2]concat=n=3:v=1:a=0[out]' -map '[out]' "+dir+"output.mp4";