Eu tenho um aplicativo, em execução no Playframework, que precisa codificar alguns arquivos de vídeo. eu usei

Process pr = Runtime.getRuntime().exec(execCode)

para isso (e funciona perfeitamente), mas como eu preciso de ambos, o fluxo de saída e o fluxo de erro, estou tentando usar ProcessBuilder (como também é recomendado).

Mas não consigo fazê-lo funcionar (testando em um MacBook). Existe uma diferença fundamental entre o método Runtime e o ProcessBuilder?

Este é o meu código para ProcessBuilder (exatamente o mesmo código funciona quando substituído porRuntime.getRuntime().exec())

    String execCode = "/opt/local/bin/ffmpeg -i file [...]"; 
    ProcessBuilder pb = new ProcessBuilder(execCode);
    pb.redirectErrorStream(true);
    pb.directory(new File("/Users/[...]/data/"));
    Process pr = pb.start();

Esta é a saída do console:

11:00:18,277 ERROR ~ There was a problem with with processing MediaFile[13] with error Error during coding process: Cannot run program "/opt/local/bin/ffmpeg -i /Users/[...]/data/media/1/1/test.mov [...] /Users/[...]/data/media/1/13/encoded.mp3" (in directory "/Users/[...]/data"): error=2, No such file or directory
java.lang.Exception: Error during coding process: Cannot run program "/opt/local/bin/ffmpeg -i /Users/Luuk/Documents/Java/idoms-server/data/media/1/1/test.mov -y -f mpegts -acodec libmp3lame -ar 48000 -b:a 64000 -vn -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -subq 5 -trellis 1 -refs 1 -coder 0 -me_range 16 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 200k -maxrate -1 -bufsize -1 -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -level 30  -g 30 -async 2 /Users/Luuk/Documents/Java/idoms-server/data/media/1/13/encoded.mp3" (in directory "/Users/Luuk/Documents/Java/idoms-server/data"): error=2, No such file or directory
    at logic.server.MediaCoder.encodeMediaFile(MediaCoder.java:313)
    at logic.server.MediaCoder.doJob(MediaCoder.java:54)
    at play.jobs.Job.doJobWithResult(Job.java:50)
    at play.jobs.Job.call(Job.java:146)
    at play.jobs.Job$1.call(Job.java:66)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:98)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:206)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:680)
Caused by: java.io.IOException: Cannot run program "/opt/local/bin/ffmpeg -i /Users/Luuk/Documents/Java/idoms-server/data/media/1/1/test.mov -y -f mpegts -acodec libmp3lame -ar 48000 -b:a 64000 -vn -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -subq 5 -trellis 1 -refs 1 -coder 0 -me_range 16 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 200k -maxrate -1 -bufsize -1 -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -level 30  -g 30 -async 2 /Users/Luuk/Documents/Java/idoms-server/data/media/1/13/encoded.mp3" (in directory "/Users/Luuk/Documents/Java/idoms-server/data"): error=2, No such file or directory
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:460)
    at logic.server.MediaCoder.encodeMediaFile(MediaCoder.java:189)
    ... 11 more
Caused by: java.io.IOException: error=2, No such file or directory
    at java.lang.UNIXProcess.forkAndExec(Native Method)
    at java.lang.UNIXProcess.<init>(UNIXProcess.java:53)
    at java.lang.ProcessImpl.start(ProcessImpl.java:91)
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:453)
    ... 12 more