Develop Reference

How to find Camera resolution and aspect ratio in android

I want to get supported camera resolution preview size and aspected ratio in list view like i have shown in the pictures. Currently i am doing this which only show me a list of resolution width and height but i also want to show aspect ration.
public void find_camera_resolution()
{
Camera mCamera = Camera.open();
Camera.Parameters params = mCamera.getParameters();
List<Camera.Size> sizes = params.getSupportedPreviewSizes();
int widths[] = new int[params.getSupportedPreviewSizes().size()];
int heights[] = new int[params.getSupportedPictureSizes().size()];
Camera.Size mSize;
for (Camera.Size size : sizes) {
Toast.makeText(this,"Available resolution: "+widths.length+" "+size.height,Toast.LENGTH_LONG).show();
mSize = size;
}
}
But i want to show like this in the picture

The aspect ratio is just the the ratio of the resolution. So you (just) need to find the Greatest Common Divisor of width and height, divide the both values by the divisior and then you got your ratio.
For example 1600x720 -> GCD: 80 -> 1600/80=20, 720/80=9 -> aspect ratio: 20:9
There are a lot of existing algorithms to solve the Createst Common Divisor Problem and there existist already some implementations which you can use.
Sample source code are here:
int gcd=find_greatest_common_divisor_of_two_number(widths[i], heights[i]);
String ratio =(widths[i]/gcd)+":"+(heights[i]/gcd);
private static int find_greatest_common_divisor_of_two_number(int number1, int number2) {
//base case
if(number2 == 0){
return number1;
}
return find_greatest_common_divisor_of_two_number(number2, number1%number2);
}

Camera Preview distorted

I cannot help myself anymore, I have read every thread about this on stackoverflow, but nothing would fix my problem.
I try to set up my camera preview in a FrameLayout, everything works fine. I determine the correct size for the preview with this code:
private Camera.Size getBestPreviewSize(int width, int height,
Camera.Parameters parameters) {
Camera.Size result = null;
for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
if (size.width <= width && size.height <= height) {
if (result == null) {
result = size;
} else {
int resultArea = result.width * result.height;
int newArea = size.width * size.height;
if (newArea > resultArea) {
result = size;
}
}
}
}
return (result);
}
Afterwards I apply it to my camera:
Camera.Parameters params = mCamera.getParameters();
Camera.Size size = getBestPreviewSize(width, height, params);
params.setPreviewSize(size.width, size.height);
params.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
mCamera.setParameters(params);
The Preview is still distorted afterwards, and my FrameLayout, which I expected to have the same size as the Preview Size I calculated, remains Fullscreen.
Fullscreen means 1920x1200
Preview Size means 1920x1080
So what I did is I set my Size of the FrameLayout manually to the calculated Preview Size. Then, however, my Preview looks even more skewed.
I have no idea what I am doing wrong. I thought when I use a supported Preview Size, this should not happen.
UPDATE:
I ran my application on another device, there everything works fine. Can this be a hardware bug? The device that is not working for me is the Nexus 7 Tablet.

I have finally come to a solution, this is really related to the hardware. There is a bug with some devices:
Bug-Report
The workaround:
This is a known low-level issue with some devices; they require that the still picture size and the preview size have matching aspect ratios, to avoid stretching artifacts.
If possible for your application, match the aspect ratios for setPreviewSize and setPictureSize.
Hope this helps you as well!

Android Camera.Parameters setPictureSize not working

I am trying to set the best possible output picture size in my camera object. So that, i can get a perfect downscaled sample image and display it.
During debugging i observed i am setting output picture size exactly the size of my screen dimensions. But when i DecodeBounds of the returned image by camera. I get some larger number!
Also i am not setting my display dimensions as expected output picture size. Code used to calculate and set the output picture size is given below.
I am using this code for devices having API level < 21, so using camera shouldn't be a problem.
I don't have any idea of why i am getting this behavior. Thanks in advance for help!
Defining Camera parameter
Camera.Parameters parameters = mCamera.getParameters();
setOutputPictureSize(parameters.getSupportedPictureSizes(), parameters); //update paramters in this function.
//set the modified parameters back to mCamera
mCamera.setParameters(parameters);
Optimal picture size calculation
private void setOutputPictureSize(List<Camera.Size> availablePicSize, Camera.Parameters parameters)
{
if (availablePicSize != null) {
int bestScore = (1<<30); //set an impossible value.
Camera.Size bestPictureSize = null;
for (Camera.Size pictureSize : availablePicSize) {
int curScore = calcOutputScore(pictureSize); //calculate sore of the current picture size
if (curScore < bestScore) { //update best picture size
bestScore = curScore;
bestPictureSize = pictureSize;
}
}
if (bestPictureSize != null) {
parameters.setPictureSize(bestPictureSize.width, bestPictureSize.height);
}
}
}
//calculates score of a target picture size compared to screen dimensions.
//scores are non-negative where 0 is the best score.
private int calcOutputScore(Camera.Size pictureSize)
{
Point displaySize = AppData.getDiaplaySize();
int score = (1<<30);//set an impossible value.
if (pictureSize.height < displaySize.x || pictureSize.width < displaySize.y) {
return score; //return the worst possible score.
}
for (int i = 1; ; ++i) {
if (displaySize.x * i > pictureSize.height || displaySize.y * i > pictureSize.width) {
break;
}
score = Math.min(score, Math.max(pictureSize.height-displaySize.x*i, pictureSize.width-displaySize.y*i));
}
return score;
}

Finally i resolved the issue after many attempts! Below are my findings:
Step 1. If we are already previewing, call mCamera.stopPreview()
Step 2. Set modified parameters by calling mCamera.setParameters(...)
Step 3. Start previewing again, call mCamera.startPreview()
If i call mCamera.setParameters without stopping preview (Assuming camera is previewing). Camera seems to ignore the updated parameters.
I came up with this solution after several trail and errors. Anyone know better way to update parameters during preview please share.

How to solve distorted image issue in android custom camera for galaxy S4

I am working on custom camera application for android. The problem is that the camera capture and showing preview good in other devices (example Samsung Galaxy S3) , but It shows distorted
image on Galaxy s4, Can any one help me??
My code for Picturesize() method is as follows:
Camera.Size getBestPicturSize(int width, int height, Camera.Parameters parameters) {
Camera.Size result=null;
float dr = Float.MAX_VALUE;
float ratio = (float)width/(float)height;
for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
float r = (float)size.width/(float)size.height;
if( Math.abs(r - ratio) < dr && size.width <= width && size.height <= height ) {
dr = Math.abs(r - ratio);
result = size;
}
}
return result;
}

I had the same problem, if you mean that photos were taken with aspect ratio 4:3 and saved with aspect ratio 16:9 (they were outstretched). My problem was, that since I chose one of supported PictureSizes, I didn't do the same with the PreviewSizes.
Supported PictureSizes for Samsung G S4 are only with aspect ratio 16:9, however default PreviewSize was set to 1440x1080, which is 4:3. When I set both sizes with the same aspect ratio, picture was taken with no distortion.
Hope it will help.

Camera.getParameters() return null on Galaxy Tab

Here is my surface-changed event handling code:
public void surfaceChanged(SurfaceHolder holder,
int format, int width,
int height) {
Camera.Parameters parameters = camera.getParameters();
Camera.Size size = getBestPreviewSize(width, height,
parameters);
//...
}
private Camera.Size getBestPreviewSize(int width, int height,
Camera.Parameters parameters) {
Camera.Size result = null;
// it fails with NullPointerExceptiopn here,
// when accessing "getSupportedPreviewSizes" method:
// that means "parameters" is null
for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
///...
}
}
I initialize camera like this:
#Override
public void onResume() {
super.onResume();
camera = Camera.open();
}
This problem doesn't occur on my Galaxy S Plus neither it happen on LG Optimus Black phone. Has anyone thoughts what's wrong here?

I've solved this.
parameters.getSupportedPreviewSizes()
Returns NULL on Galaxy Tab. So I just make a check if it is null and don't set new preview size in such case. To this conclusion I've came after looking into standard Camera application sources.

Looks like the camera variable was never initialized so you are calling getParameters() on null. Try calling camera = Camera.open(); first

camera initialization depends a lot on the specific device. For instance a specific Samsung device GT5500 is reporting null (width = 0, height = 0) as a valid resolution for preview, but crashes the whole phone ("hard" reboot) if you try to use it. We experienced it with mixare augmented reality engine (http://www.mixare.org) and it was PITA to debug (since we didn't have the phone and could not reproduce the bug on any other hardware).
However, about getting the "right" preview size you can take a look at our code (it's a free and open source app) on github. In the file: https://github.com/mixare/mixare/blob/master/src/org/mixare/MixView.java (row 871 and onwards)
List<Camera.Size> supportedSizes = null;
//On older devices (<1.6) the following will fail
//the camera will work nevertheless
supportedSizes = Compatibility.getSupportedPreviewSizes(parameters);
//preview form factor
float ff = (float)w/h;
Log.d("Mixare", "Screen res: w:"+ w + " h:" + h + " aspect ratio:" + ff);
//holder for the best form factor and size
float bff = 0;
int bestw = 0;
int besth = 0;
Iterator<Camera.Size> itr = supportedSizes.iterator();
//we look for the best preview size, it has to be the closest to the
//screen form factor, and be less wide than the screen itself
//the latter requirement is because the HTC Hero with update 2.1 will
//report camera preview sizes larger than the screen, and it will fail
//to initialize the camera
//other devices could work with previews larger than the screen though
while(itr.hasNext()) {
Camera.Size element = itr.next();
//current form factor
float cff = (float)element.width/element.height;
//check if the current element is a candidate to replace the best match so far
//current form factor should be closer to the bff
//preview width should be less than screen width
//preview width should be more than current bestw
//this combination will ensure that the highest resolution will win
Log.d("Mixare", "Candidate camera element: w:"+ element.width + " h:" + element.height + " aspect ratio:" + cff);
if ((ff-cff <= ff-bff) && (element.width <= w) && (element.width >= bestw)) {
bff=cff;
bestw = element.width;
besth = element.height;
}
}
Log.d("Mixare", "Chosen camera element: w:"+ bestw + " h:" + besth + " aspect ratio:" + bff);
//Some Samsung phones will end up with bestw and besth = 0 because their minimum preview size is bigger then the screen size.
//In this case, we use the default values: 480x320
if ((bestw == 0) || (besth == 0)){
Log.d("Mixare", "Using default camera parameters!");
bestw = 480;
besth = 320;
}
parameters.setPreviewSize(bestw, besth);
As you see we're not using directly the call to getSupportedPreviewSizes of the Camera class, but instead added a compatibility layer (the code is here: https://github.com/mixare/mixare/blob/master/src/org/mixare/Compatibility.java ) because we needed compatibility with older phones. If you don't want to support older android releases you can use the method of the Camera class directly.
HTH
Daniele