cubase 7 and video

does anyone know how to export video and audio in cubase? all i get is the sound no vid…
also…the play back in video player is terrible…
any thoughts welcome

Cubase does not export audio and video together. You need to export your mix to a file, then replace the audio in the video file.
You do this with a function called “replace audio in video file” from within Cubase.
Before you do this. Make a copy of the video file you want to replace the audio in, and put that in it’s own folder.
Export your mix, then replace the audio in the copied video file. This will leave your original untouched.
Look in the manual on page 679:

Replacing the audio in a video file
Once you have edited all audio and MIDI data to the video and created a final mix, you will need to put the new audio back with the video. You can do this by embedding the audio in another stream within the video container file.
To replace the audio stream in a video file, proceed as follows:
1.Place the left locator at the start of the video file in Cubase. This will ensure that your audio and video streams are synchronized.
2.Open the File menu and select the Audio Mixdown option from the Export submenu to export the audio file you wish to insert into the video container file (for detailed information on this function, see the chapter “Export Audio Mixdown” on page 638).
3.From the File menu, select “Replace Audio in Video File…”.
A file dialog opens prompting you to locate the video file.
4.Select the video file and click Open.
Next, you are prompted to locate the corresponding audio file.
5.Select the audio file and click Open.
The audio is added to the video file, replacing its current audio stream.
Once the process is completed, open the video file in a native media player and check for proper synchronization.