It was actually in Nagrace NT-V6 firmware the boot.mp4 video bootanimation, here is the commit
2014-12-30 e296bf9 Android->BootAnimation:添加开机视频功能，默认为/system/media/boot.mp4(可修改BOOTVIDEO_FILE改变格式),支持mp4,wmv等主流格式
Maybe it can also be implemented in Firefly firmware and boot-time increased to 15 seconds for bootanimation/video to play longer.
Or a setting in build.prop or Android Settings menu to increase/reduce boot-time so that it plays your own bootanimation/video longer/shorter.
