title: How to fix the frame rate of camera in Android phone
body: <p>I want to fix the frame rate of camera preview in Android, i.e., 20fps, or 30 fps. However, we find the frame rate is unstable. </p>
  
  <p>In the android document, it is said that the frame rate is fluctuated between the minimum frame rate and the maximum one which are defined in getSupportedPreviewFpsRange.
  <a href="https://developer.android.com/reference/android/hardware/Camera.Parameters.html#getSupportedPreviewFpsRange%28%29" rel="nofollow noreferrer">https://developer.android.com/reference/android/hardware/Camera.Parameters.html#getSupportedPreviewFpsRange%28%29</a></p>
  
  <p>My questions are:
  1) Which factors influence the frame rate? exposure time, white balance, frame resolution, background CPU loading, and etc.?
  2) Is there any method to fix the frame rate by customised above factors? 
  3) In my project, higher frame rate is better. If the frame rate is unstable in the end. Can I increase the minimum frame rate? or fix the minimum frame rate?
  4) It seems that the video taking is somewhat different with preview model, Can I fix the frame rate or minimum frame rate of video taking in Android?</p>
  
  <p>Finally, we found that IOS can fix the frame rate using videoMinFrameDuration and 
  videoMaxFrameDuration.</p>
  
  <p>Thanks.</p>