Reduce size of a large JPEG without changing resolution

Question

I have a JPEG from my camera that is 3264x1952. This file is about 1.7 megabytes.

I'm wondering is there anyway to compress this image to a smaller file size without changing the resolution. i.e. I want my resultant image to also be 3264x1952.

I cannot even open this JPEG as a bitmap without using the inSampleSize option to scale down the image.

Anyone know what my options are? Is there any way to reduce color bit depth/increase compression/reduce quality?

edit: I'm specifically looking for a solution for Android. Main problem being I can't open the full res JPEG without hitting a OOM error, so I don't know how to proceed.

Ideally I'd like to do:

bitmap.compress(Bitmap.CompressFormat.JPEG, 50, out);

But the application will crash when I do:

Bitmap bitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());

possible duplicate of [Programatically Reducing JPEG file size](http://stackoverflow.com/questions/6830478/programatically-reducing-jpeg-file-size) — Burkhard, Jun 26 '13 at 06:57
@Segi I can't reduce my image quality because I can't open the file as a bitmap in the first place... — blinduck, Jun 26 '13 at 07:00
Maybe this helps, there is a section about loading a scaled down version of an IMage into mem: http://developer.android.com/training/displaying-bitmaps/load-bitmap.html — Fildor, Jun 26 '13 at 07:15

score 1 · Answer 1 · answered Jun 26 '13 at 07:21

you can use the BitmapFactory.decodeFile method that takes as second paramter a BitmapFactory.Options object and use inSampleSize to scale the image. For instance an inSampleSize = 2 will produce an output image of width/2 and height/2, . Just remember that your bitmap need always width x heigth x 4 bytes of memory

Ken · Answer 2 · 2013-06-26T07:37:36.323

0

I think you want to use BitmapFactory.decodeStream, taking in a stream from the JPEG file. You can modify the density before the bitmap is returned.

edited Jun 26 '13 at 07:37

answered Jun 26 '13 at 07:19

Ken

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score 0 · Answer 3 · answered Jun 26 '13 at 07:33

You need to scale down your image.

http://developer.android.com/training/displaying-bitmaps/load-bitmap.html.

Use appropriate Bitmap.decode method and scale down the image.

Bitmap.decode

Example :

Call the method with the required parameters.

public static Bitmap decodeFile(File f,int WIDTH,int HIGHT){
 try {
     //Decode image size
     BitmapFactory.Options o = new BitmapFactory.Options();
     o.inJustDecodeBounds = true;
     BitmapFactory.decodeStream(new FileInputStream(f),null,o);

     //The new size we want to scale to
     final int REQUIRED_WIDTH=WIDTH;
     final int REQUIRED_HIGHT=HIGHT;
     //Find the correct scale value. It should be the power of 2.
     int scale=1;
     while(o.outWidth/scale/2>=REQUIRED_WIDTH && o.outHeight/scale/2>=REQUIRED_HIGHT)
         scale*=2;

     //Decode with inSampleSize
     BitmapFactory.Options o2 = new BitmapFactory.Options();
     o2.inSampleSize=scale;
     return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
 } catch (FileNotFoundException e) {}
 return null;
}

Reduce size of a large JPEG without changing resolution

3 Answers3