Runtime.getRuntime().exec() not working in a module

Wowza Developer Dojo
1

Hi,

I need to run a process using java’s Runtime.getRuntime().exec() when a stream gets unPublished. So I implemented IMediaStreamActionNotify3 on my Module and registered the notifier with the stream. In onUnPublish(), I tried to execute Runtime.getRuntime().exec(). As i can see, it starts the process, but execution of the created process just hangs(i can see process name in my taskmanager with 0% cpu and no change in memory). If I close the instance of the server, the created process executes and gives me desired output.

Note : Am running wowza in windows 8/64 bit. Behaviour is same if i run server instance from eclipse or as standalone application(startup.bat) . If i execute the same command through simple java class with a main() method, it just works fine.

Command i was executing was:

"ffmpeg -y -i in.mp4 -i in2.mp4 -filter_complex “[0] trim=start=40:end=70:duration=30, setpts=PTS-STARTPTS, scale=512:288 [v2] ;[0] trim=start=60:end=80:duration=20, setpts=PTS-STARTPTS, scale=512:288 [v1] ; [1] trim=start=0:end=30:duration=30, setpts=PTS-STARTPTS, scale=512:288 [v4] ; [1] trim=start=20:end=40:duration=20, setpts=PTS-STARTPTS, scale=512:288 [v3] ; [v2][v4][v1][v3] concat=n=4:v=1:a=0 [outv]; [0] atrim=start=40:end=70:duration=30, asetpts=PTS-STARTPTS [a2] ;[0] atrim=start=60:end=80:duration=20, asetpts=PTS-STARTPTS [a1] ; [1] atrim=start=0:end=30:duration=30, asetpts=PTS-STARTPTS [a4] ; [1] atrim=start=20:end=40:duration=20, asetpts=PTS-STARTPTS [a3]; [a2][a4][a1][a3] concat=n=4:v=0:a=1 [outa] " -map [outv] -map [outa] -profile:v main -level 3.1 -b:v 440k -ar 48000 -ab 128k -s 720x400 -vcodec h264 -acodec libvo_aacenc test.mp4”

ffmpeg with 2 input files(usage of -i twice): ffmpeg hangs till i close server instance and once i close server, works fine

Other command(works fine):

"ffmpeg -y -i in.mp4 -filter_complex “[0] trim=start=40:end=70:duration=30, setpts=PTS-STARTPTS, scale=512:288 [v2] ;[0] trim=start=60:end=80:duration=20, setpts=PTS-STARTPTS, scale=512:288 [v1] ; movie=in2.mp4, trim=start=0:end=30:duration=30, setpts=PTS-STARTPTS, scale=512:288 [v4] ; movie=in2.mp4, trim=start=20:end=40:duration=20, setpts=PTS-STARTPTS, scale=512:288 [v3] ; [v2][v4][v1][v3] concat=n=4:v=1:a=0 [outv]; [0] atrim=start=40:end=70:duration=30, asetpts=PTS-STARTPTS [a2] ;[0] atrim=start=60:end=80:duration=20, asetpts=PTS-STARTPTS [a1] ; amovie=in2.mp4, atrim=start=0:end=30:duration=30, asetpts=PTS-STARTPTS [a4] ; amovie=in2.mp4, atrim=start=20:end=40:duration=20, asetpts=PTS-STARTPTS [a3]; [a2][a4][a1][a3] concat=n=4:v=0:a=1 [outa] " -map [outv] -map [outa] -profile:v main -level 3.1 -b:v 440k -ar 48000 -ab 128k -s 720x400 -vcodec h264 -acodec libvo_aacenc test.mp4”

ffmpeg with 1 input file(usage of -i once. 2nd input is used with movie/amovie filter option, a work around to replace usage of -i option): ffmpeg executes normal

Both commands works fine from a simple java class with main() method(as module is java class too i expect both the commands to work on wowza module too). What difference it makes to execution if i supply ffmpeg 2 inputs(-i twice) through wowza module? Can there be any memory/cpu usage contrains on my newly created process by the instance of wowza server?

Krishna

2

Hi Krishna,

I’m not really sure why it is working in some cases but not others but this appropriately named article, When Runtime.exec() won’t, may indicate why.

In the past, I have used ProcessBuilder instead of Runtime.exec() in a separate thread to run external processes from within Wowza.

The following is a class that I have used previously to write a series of timestamped images out to an mp4 file. It was run every 24 hours on a timer thread to process the images. I know it is different to what you are doing but it does show how to invoke ffmpeg from within wowza using ProcessBuilder.

	private class TimeLapseWriter extends Thread {
		Calendar cal;
		File filePath;
		private TimeLapseWriter(File filePath) {
			cal = Calendar.getInstance();
			this.filePath = filePath;
			cal.add(Calendar.DATE, -1);
		}
		public void run() {
			String yesterday = dateFormat.format(cal.getTime());
			File yesterdaysFolder = new File(filePath.getAbsolutePath()
					+ File.separator + yesterday);
			if (yesterdaysFolder.exists()) {
				try {
					File outFolder = new File(appInstance
							.getStreamStoragePath()
							+ File.separator + yesterday);
					if (!outFolder.exists())
						outFolder.mkdirs();
					String[] parts = fileName.split("\\.");
					String ffmpegPath = props.getPropertyStr("ffmpegPath",
							"/usr/bin/ffmpeg");
					String[] execStr = {
							ffmpegPath,
							"-f",
							"image2",
							"-r",
							"10",
							"-i",
							yesterdaysFolder.getAbsolutePath() + File.separator
									+ parts[0] + "%04d." + parts[1],
							"-vcodec",
							"libx264",
							"-vpre",
							"default",
							"-vpre",
							"baseline",
							"-s",
							"512x288",
							outFolder.getAbsolutePath() + File.separator
									+ streamName + ".mp4" };
					for (String arg : execStr)
						System.out.println(arg);
					ProcessBuilder pb = new ProcessBuilder(execStr);
//					pb.environment().put("LD_LIBRARY_PATH",
//							"/usr/local/av/lib:/usr/lib:/lib");
//					pb
//							.environment()
//							.put("PATH",
//									"/usr/local/av/bin:/usr/kerberos/bin:/usr/bin:/bin:/usr/sbin:/sbin");
					pb.redirectErrorStream(true);
					Process p = pb.start();
					BufferedReader in = new BufferedReader(
							new InputStreamReader(p.getInputStream()));
					String line = null;
					while ((line = in.readLine()) != null) {
						System.out.println(line);
					}
					if (p.waitFor() == 0) {
						logger.info("File " + outFolder + File.separator
								+ streamName + ".mp4 Written Successfully.");
					} else {
						logger.error("File " + outFolder + File.separator
								+ streamName + ".mp4 Write Error.");
					}
				} catch (IOException e) {
					e.printStackTrace();
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}

Hope this helps.

Roger.

3

Hi,

Good to hear it is working. It’s a long time since I did anything with this and I do recall having similar issues with Runtime.exec.

Roger.

4

Hi Roger,

Appreciate ur reply. The link provided by u is very detailed. Applying the measures described(handling error and input streams of process) in that post helped me to fix my ‘process blocking’ problem. Thanx man.

Krishna