On N90 there is a small delay between video and audio (audio is shifted forward). I tried sample VRex application and it has the same delay. But standard application doesn't have the delay. With this delay the recording itself is useless. Maybe Nokia engineers can help with this otherwise I would really regret that I started to develop video recording application on this device.
I tried every setting, changing audio priority, reducing frame rate, bitrate etc. Nothing helps. I achieved the same properties for audio and video streams in MP4 as in standard application (checked with MP4Box), but the delay persists. Maybe they use some custom MMF plug-in commands to shift audio or to start video and audio simultaneously.