如何压缩Camera.takepicture拍摄的照片

Question

I'm developing an app where the user has the ability to take a picture through my CameraActivity (SurfaceView+Camera) and save it. After that the bitmap will be processed.

Said that let me walk you through details. The picture is taken with:

mCamera.takePicture(null, null, new PictureCallback() {...}

I'm not specifying .jpeg quality.
Testing with HTC One S, the picture is taken and then saved. The picture size never exceeds 100kb
Testing with Samsung GT-I9000, the picture is taken and then saved but the difference here is the size, it exceeds 1,2Mb.

Since I'll need to process the bitmap latter on I'm having some OutOfMemory issues with the GT-I9000 when I try to decode the bimap to process it:

try {
    FileInputStream fis = new FileInputStream(new File(imagePath));
    Bitmap savedPicture = BitmapFactory.decodeStream(fis);

I've tried to change Camera Parameters .setJpegQuality(quality) but I it didn't made a huge difference.

The image will occupy all the screen size and I used this approach Loading Large Bitmaps Efficiently It worked, I got rid of OutOfMemory Exceptions but still I've some questions:

1. File size differences between devices? I assume HTC One S is better than GT-I9000 so why doesn't save bigger pictures?

2. Image resolution, HTC One S 640x480, GT-I9000 2560x1920 why? Well this answer the first question, but why is this happening?

Thanks for your time ;)

Answer 1

Your problem is not with the image compression, but with resolution, ie size. Different Android devices have different default Picture sizes. But luckily, you have the Camera.Parameters.setPictureSize(int width, int height) method. You can set the size any time before you call Camera.takePicture() like this:

Camera.Parameters param = mCamera.getParameters();
param.setPictureSize(640, 480);
mCamera.setParameters(param);

Note that different Android devices support different picture sizes, too. Ie you cannot set an arbitrary size, you must choose one from the list specific to the device. There is a method Camera.Parameters.getSupportedPictureSizes().

Note that the supported picture sizes on the same device are different for the two cameras (if the device has front facing camera and rear facing camera). Open the correct camera before you start the queries and sets.

Finally, I should confess that all devices I ever heard about, all supported 640x480 picture size.