Make missing ffmpeg a fatal error. Closes #554

config/config.go

@@ -211,7 +211,7 @@ func (c *config) GetFFMpegPath() string {
 	cmd := exec.Command("which", "ffmpeg")
 	out, err := cmd.CombinedOutput()
 	if err != nil {
-		log.Debugln("Unable to determine path to ffmpeg. Please specify it in the config file.")
+		log.Fatalln("Unable to determine path to ffmpeg. Please specify it in the config file.")
 	}
 
 	path := strings.TrimSpace(string(out))