Develop Reference

Android camera (deprecated) preview resizes when recording

The problem appears on my Nexus 6P device. After going through all the motions to detect optimal previews, aspect ratios, video sizes etc, I end up with the following:
SurfaceView dimens 2392x1440 (full screen)
Once re-measured with the aspect ratio of the camera preview resolution, this changes to 2560x1440 or 2392x1351 depending on the calculation method.
Camera preview size: 1920x1080
This is set on the camera params using setPreviewSize():
params.setPreviewSize(mOptimalPreviewSizes.width, mOptimalPreviewSizes.height);
Media recorder video size: 1920x1080 (forced by the settings)
This is set on the media recorder:
mMediaRecorder.setVideoSize(mOptimalVideoSize.width, mOptimalVideoSize.height);
When I click the record button, the camera preview 'zooms in', i.e. resizes to video size. If I change the video size setting to for example 3840x2160, the preview works fine with no resizing.
I was under impression that it is possible to set video size separatly to the preview size, so I'm a bit confused to why I'm seeing this and how can I work around this.
EDIT:
As an example, OpenCamera seems to be able to separate preview surface resolution from video resolution. https://sourceforge.net/p/opencamera/code/ci/master/tree/src/net/sourceforge/opencamera/
To make sure, I've added a line just before video_recorder.prepare(); to set a custom video size (video_recorder.setVideoSize(640,480);). The preview surface was still measuring near full screen at 2392x1351, and camera preview was still set to 1920x1080. I've also double checked the resulting video and it was 640x480 as expected. Unfortunately I cannot see anything in their code that would indicate how this is achieved.
EDIT 2:
I've also noticed that this 'zooming' action always happens to a specific resolution/value. Regardless of whether I'm recording at 1920x1080 or 320x200, the preview gets zoomed and looses about a cm of the picture that was available before the recording started. The end video has the expected cropping in relation to the resolution.

The problem seems to be related to the video stabilisation. I suppose this actually makes sense as stabilising against shakes usually requires cropping and when the preview resolution is already significantly lower than the surface size, it causes the picture to 'jump' or 'zoom' in. Removing video stabilisation fixes the issue.

Android camera ensure fast response onPictureTaken

I have created a custom camera activity (pretty much followed the Android tutorial)
I implemented a SurfaceView to use a preview and an ImageView to display the image taken on OnPictureTaken
Picture taken takes a while to show up and differs from the preview in terms of aspect ratio, size, lighting, white balance. (probably I didn't set the params properly). The quality of the picture doesn't really matter to me. I just want the app to be responsive, ie still picture shows up immediately, and is identical to the preview.
So what I ended up doing was remove the ImageView and only have the SurfaceView. When the camera button is clicked, I stopPreview(). However, now I don't know how to save the SurfaceView content to bitmap/file. From what I read there isn't really a way to SurfaceView to return a bitmap.
What would be a better way to implement the camera? To reiterate, I need to be able to get a bitmap that is identical to the preview, and have that still image shown to the user immediately.

Android - Distorted Camera Preview

I am currently writing an android app which runs displays a circle drawable on the preview frame, runs edge detection and then takes a photo once the user lines up a coin perfectly in the circle.
For some reason (despite being fullscreen with no title etc.), I am started to realize the camera preview is every so slightly distorted.
I have tried setting the previewsize to 480x640 while also setting the surfaceholder size to 480x640, however if I save the preview to bitmap and also take a photo, you can notice the distortion.
Has anybody else had this kind of problem / or have any ideas as to a solution?

I have encountered the same issue.
Hopefully I found that ApiDemos includes a working example with Camera.
You can find it here: com.example.android.apis.graphics.CameraPreview.
I didn't digged the example, but I saw it's working fine just as my real camera, no distortion at all.

How is the camera preview connected with the final image output?

I've always been under the impression that the preview and the final output are not connected in any way; meaning that I can set the preview to be some arbitrary dimension and that the final JPG will be whatever specific resolution I set in to be in the params, but I just ran into a very odd situation where the image data coming back in the byte[] that's in the jpg callback is different, depending on what dimensions I set my preview to.
Can someone enlighten me on what actual relationship the preview has on the final JPG? (or point me to documentation on said relationship).
TIA
[Edit]
As per ravi's answer, this was my assumption as well, however, I see no alternative but to surmise that they are, in fact, directly connected based on the evidence. I'll post code if necessary (though there's a lot of it) but here's what I'm doing.
I have a preview screen where the user takes a photo of themselves. I then display the picture captured (from the jpg callback bitmap data) in a subsequent draw view and allow them to trace a shape over their photo. I then pass the points of their polygon into a class that cuts that shape out of the original image, and gives back the cut image.
All of this works, BUT depending on how I present the PREVIEW, the polygon cutting class crashes on an array out of bounds index as it tries to access pixels on the final image that simply don't exist. This effect is produced EXCLUSIVELY by altering the shape of the preview View's dimensions. I'm not altering ANYTHING else in the code, and yet, just by mis-shaping my preview view, I can reproduce this error 100% of the time.
I can't see an explanation other than that the preview and the final are directly connected somehow, since I'm never operating on the preview's data, I only display it in a SurfaceView and then move on to deal exclusively with the data from the JPG callback following the user having taken their photo.

There is no relation between the preview resolution and the final image that is captured.
They are completely independent (at least for the still image capture). The preview resolution and the aspect ratio are not interrelated with the final image resolution and the aspect ratio in anyway.
In the camera application that I have written, the preview is always VGA but the image I capture varies from 5M to VGA (depending on the device capability)
Perhaps if you can explain the situation it would be more helpful.

We are currently developing a camera application and face very similiar problems. In our case, we want to display a 16:9 preview, while capturing a 4:3 picture. On most devices this works without any problems, but on some (e.g. Galaxy Nexus, LG Optimus 3D), the output camera picture depends on the preview you've chosen. In our case the outcoming pictures on that devices are distorted when the preview ratio is different from the picture ratio.
We tried to fix this, by changing the preview resolution to a better one just before capturing the image. But this does not work on some devices and occure error while starting the preview again after capturing is finished.
We also tried to fix this, by enlarging the SurfaceView to fullscreen-width and "over fullscreen"-height to make a 16:9 preview out of a 4:3 preview. But this does not work, because SurfaceViews can not be higher then screenheight.
So there IS any connection on SOME devices, and we really want to know, how to fix/workaround this.

How does android handle differences between preview size/ratio and actual SufaceView size?

I'm writing a small android app where a user can place an image inside the live preview of the camera and take a picture of this. The app will then combine the two images appropriately -- All of this is working fine.
I understand you can get/set the PreviewSize using Camera.getParameters(), I assume this is related to the size of the realtime "camera feed".
However, the size of my SurfaceView where the camera preview is shown is different from the reported (and used) PreviewSizes. For example, in the emulator my available SurfaceView happens to be 360x215, while the PreviewSize is 320x240. Still, the entire SurfaceView is filled with the preview.
But the picture that's generated in the end is (also?) 320x240. How does android compensate for these differences in size and aspect ratio? Is the image truncated?
Or am I simply misunderstanding what the PreviewSize is about - is this related to the size of the generated pictures, or is it related to the "realtime preview" that's projected on the SurfaceView? Are there any non-trivial Camera examples that deal with this?
I need to know how what transformation takes place to, eventually, copy/scale the image correctly into the photo, hence these questions.

I am trying to figure this out myself. Here is what I found out so far..
The surface view has an internal surface called mSurface which is actually used as camera feed and the encoder feed. So this buffer has to be the actual size at which you want do the recording.
You can set the size of this mSurface to be independent of the SurfaceView by using the setFixedSize method
Now you might want to perform a HD recording so the mSurface needs to 1280x760 resolution but you SurfaceView can't be that big (Assuming you are running it on a phone with a WVGA screen). So you try to set to a smaller resolution than 1280x760 which also maintains the same aspect ratio.
Android now performs a resizing on the HD buffer to get the preview resolution, cropping is not done, it is just resized to the SurfaceView reoslutions
So at this point both the mSurface and the previewSize that you set to the camera is the same resolution and hence the resultant video recording will also be of the same resolution.
That being said I am still struggling to get my VGA recorder to work on Nexus S, it is working on a LG Maha device. :)