When playing a MP4 file VLC tells me the video and audio codecs are mp4v and mp4a. The quality is good at low bitrates. However, the MP4 Streaming Faq tells me that mp4v means raw MPEG4 streams. What does this mean? It clearly isn't unencoded video.
VLC is telling you the truth - it looks to me (without actually seeing the file) that your MP4 file is a MPEG-4 container with MPEG-4 codecs being used for the audio and video.
If we were talking about the MP4 container, you could see these types of codecs in them:
MP4V and MP4A stand for Mpeg 4 Video and Audio.
For better clarification of actual codecs used try: