 for camera preview images since
 API level 12; for earlier API versions, check
 <code><a href="../../../reference/android/hardware/Camera.Parameters.html#getSupportedPreviewFormats()">getSupportedPreviewFormats()</a></code>.

 <p>Note that for camera preview callback use (see
 <code><a href="../../../reference/android/hardware/Camera.html#setPreviewCallback(android.hardware.Camera.PreviewCallback)">setPreviewCallback(Camera.PreviewCallback)</a></code>), the
 <var>stride</var> value is the smallest possible