Record video with a different preview size than the resulting video file

Question

I am attempting to allow users to record video that is a different size than the actual on-screen preview that they can see while recording. This seems to be possible from this documentation concerning the getSupportedVideoSizes function which states:

If the returned list is not null, the returned list will contain at least one Size and one of the sizes in the returned list must be passed to MediaRecorder.setVideoSize() for camcorder application if camera is used as the video source. In this case, the size of the preview can be different from the resolution of the recorded video during video recording.

This suggests that some phones will return null from this fn (in my experience the Galaxy SIII does) but for those who do not, it is possible to provide a preview with a different resolution than the actual video. Is this understanding correct? Do some phones allow the behavior and others not?

Attempting a Solution:

In the official description of the setPreviewDisplay function, which is used in the lengthy process of setting up for video recording, it is mentioned that:

If this method is called with null surface or not called at all, media recorder will not change the preview surface of the camera.

This seems to be what I want, but unfortunately if I do this, the whole video recording process is completely messed up. I am assuming that this function can not be passed null or not called at all in the process of recording video. Perhaps in other contexts this is okay. Unfortunately though, this does not seem to help me.

My only next steps are to look into TextureViews and to use a preview Texture as opposed to a typical SurfaceView implementation in order to use openGL to stretch the texture to my desired size that differs from the actual resolution (and crop any excess off the screen), and then to Construct a Surface for the setPreviewDisplay function with the Surface(SurfaceTexture surfaceTexture) constructor for a Surface. I would like to avoid using a TextureView due to incompatibility below ICS, and also because this adds significant complexity.

This seems like a delicate process, but I am hoping someone can offer some advice in this area.

Thank you.

Answer 1

a.Assume the user sets the size of x,y as video size

b.Now with getSupportedVideoSizes function get the entire list and see if x,y falls in one of them and set the MediaRecorder.setVideoSize().If x,y does not fall in the getSupportedVideoSizes list,then set the default profile for the video record.

This is about the video size

Now coming to the preview size,Not much workaround options. Take a RelativeLayout which holds the SurfaceView.

<android.view.SurfaceView xmlns:android="http://schemas.android.com/apk/res/android"
 android:id="@+id/preview"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 />

preview is the name of the SurfaceView. Here i have given a sample of re-sizing it to half of the width and height.

resetCamera();  //reset the camera   

ViewGroup.LayoutParams params = preview.getLayoutParams();
RelativeLayout myRelLayout = (RelativeLayout) findViewById(R.id.myRelLayout);
params.width = (int) (myRelLayout.getWidth()/2);
params.height = (int)(myRelLayout.getHeight()/2);
preview.setLayoutParams(params);

initCamera(); //initiate the camera(open camera, set parameter, setPreviewDisplay,startPreview)

please look at the resolution of the preview and then scale down the height or width accordingly based on the video size.

Hope it helps.