mp4box does not encode any video, it is only used to re-package existing content. So my guess is that you already have an encoded video and then use
mp4box to add the
hint option. While that workflow doesn't really make sense to me at first, let me explain what
-hint option is probably called in order to introduce a so called Hint Track to the video file.
What is a hint track? Well, your video file itself is a series of bits, nothing more, and in some applications, this is very inefficient. Take the example of a server that streams the video. It has to encapsule the video into packets that are sent over the network. But how does the server know which parts of the video to put in which packet? If the server doesn't know the structure of the bitstream, it will not be able to correctly packetize it.
Here is where the hint track comes into play. It is generated to allow a streaming server to correctly packetize the video into RTP packets. Basically such a hint track says "Put part XY of the video in packet AB".
That all being said a true h.264 does not need to have a hint track for streaming, as h.264 has a Network Abstraction Layer that provides a streaming server with all the necessary information to packetize the video. Hinting is only necessary for MPEG-4 Visual videos (for example encoded with DivX or XviD).
Check if your encoder already outputs a valid
mp4 file — which one do you use actually?