Help in synchronizing DX Graphic/Text output

I need to ask: How to add text to graphics in VC++ to allow them to refresh at the same time.

I have a real-time video displayed at high frequency using DirectX.
When I add text onto the graphics, however, they tend to have different refreshing rates and the text starts to blink on top of the video.

I used a mainframe and a buffer, the variable BLT() is used for pixel display. After displaying the picture, I used the TextOut() command to display the text over the picture. Is there any way to program it so the text will refresh with the picture at same rate but not impair the quality of the picture or increase the video size on a network?