diff --git a/gtk2_ardour/transcode_ffmpeg.cc b/gtk2_ardour/transcode_ffmpeg.cc
index 56c55ff4ee..6e8bd07e93 100644
--- a/gtk2_ardour/transcode_ffmpeg.cc
+++ b/gtk2_ardour/transcode_ffmpeg.cc
@@ -114,8 +114,20 @@ TranscodeFfmpeg::probe ()
 		ffexit();
 		return false;
 	}
+
+	/* wait for ffprobe process to exit */
 	ffcmd->wait();
 
+	/* wait for interposer thread to copy all data.
+	 * SystemExec::Terminated is emitted and ffcmd set to NULL */
+	int timeout = 300; // 1.5 sec
+	while (ffcmd && --timeout > 0) {
+		usleep(5000);
+	}
+	if (timeout == 0 || ffoutput.empty()) {
+		return false;
+	}
+
 	/* parse */
 
 	std::vector<std::vector<std::string> > lines;
@@ -231,11 +243,6 @@ TranscodeFfmpeg::probe ()
 	}
 	/* end parse */
 
-
-	int timeout = 500;
-	while (ffcmd && --timeout) usleep (1000); // wait until 'ffprobe' terminated.
-	if (timeout == 0) return false;
-
 #if 0 /* DEBUG */
 	printf("FPS: %f\n", m_fps);
 	printf("Duration: %lu frames\n",(unsigned long)m_duration);