Support process options

README.md

@@ -1402,6 +1402,21 @@ command.clone()
 command.save('/path/to/output-original-size.mp4');
 ```
 
+### Child Process Options
+
+You can pass child-process options to the spawn method.
+See [child_process.spawn](https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options).
+
+```js
+// Create a detached process command to convert source.avi to MP4
+var command = ffmpeg('/path/to/source.avi')
+  .withProcessOptions({
+    detached: true
+  })
+  .format('mp4')
+  .save('/path/to/output.mp4');
+```
+
 
 ## Contributing
 

lib/processor.js

@@ -431,16 +431,18 @@ module.exports = function(proto) {
         return emitEnd(err);
       }
 
+      var options = Object.assign({
+        captureStdout: !outputStream,
+        niceness: self.options.niceness,
+        cwd: self.options.cwd,
+        windowsHide: true
+      }, self.options.processOptions || {});
+
       // Run ffmpeg
       self._spawnFfmpeg(
         args,
-        {
-          captureStdout: !outputStream,
-          niceness: self.options.niceness,
-          cwd: self.options.cwd,
-          windowsHide: true
-        }, 
-
+        options,
+
         function processCB(ffmpegProc, stdoutRing, stderrRing) {
           self.ffmpegProc = ffmpegProc;
           self.emit('start', 'ffmpeg ' + args.join(' '));
@@ -641,6 +643,21 @@ module.exports = function(proto) {
   };
 
 
+  /**
+   * Add process options to spawn
+   *
+   * @method FfmpegCommand#withProcessOptions
+   * @category Processing
+   *
+   * @see [child_process.spawn](https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options)
+   * @return FfmpegCommand
+   */
+  proto.withProcessOptions = function(options) {
+    options = options || {};
+    this.options.processOptions = options;
+    return this;
+  };
+
   /**
    * Kill current ffmpeg process, if any
    *