Android read image from sdcard. Wrong size

Question

I am creating an android app and want to read a file from sdcard and send it to a rest webservice. Everything works fine but when I read the file from sdcard its filesize is much bigger than its originalsize. A 10 KB file is getting 260 KB.

I am doing the following...

File f = new File(uri);
Log.d("ORIGINAL FILESIZE:"+f.length());

Filesize 10752 Bytes on SDCARD.

This is exactly the same size the image has on the phone.

Bitmap bmp = BitmapFactory.decodeFile(uri);
ByteArrayOutputStream bao = new ByteArrayOutputStream();

bmp.compress(Bitmap.CompressFormat.JPEG, 100, bao);
Log.d("FILESIZE AFTER:"+bao.size());

Filesize 260904 Bytes after decode / compress.

This is the filesize the server receives and writes to disk. It's the same Image and Quality but about 20 times bigger.

Does anyone know what I am doing wrong?

score 0 · Answer 1 · answered Jul 11 '12 at 15:11

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If your original file is a jpeg with high compression rate, it's normal that the decoded bitmap is much larger, especially if you use a quality of 100 in the compress() method (which means high quality).

Did you try using compress() with a lower quality value (cf documentation) ?

answered Jul 11 '12 at 15:11

sdabet

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hi but doesn't the bmp.compress method just read the already compressed image from disk?. I don't want to compress it double times. I want to leave the quality as it is. – Chris Jul 11 '12 at 15:17
not sure. Maybe not. I just need to read the image from sdcard and need to get a byte[] array. Is there a better way doing it? – Chris Jul 11 '12 at 15:26
This may help: http://stackoverflow.com/questions/6058003/beautiful-way-to-read-file-into-byte-array-in-java – sdabet Jul 11 '12 at 15:30

score 0 · Answer 2 · answered Jul 11 '12 at 15:20

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It is not wrong. Or at least it could be. The bytes rapresentation of a bitmap in memory, requires (a 32-bit image) height * widht * 4 bytes. And of course it differs from the file size becaouse of the compression.

answered Jul 11 '12 at 15:20

Blackbelt

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yea but if I write the same file to disc again then the size of the newly created file is still 20 times bigger as it was before. – Chris Jul 11 '12 at 15:23
if apply compress with the same pairo of compress algo/quality, yes it has – Blackbelt Jul 11 '12 at 15:25
I tried using the same compress level as before when I created the image. The filesize is the same now but the quality of the newly created image seems worse. – Chris Jul 11 '12 at 15:32
are you starting from the compressed image and compress it again? – Blackbelt Jul 11 '12 at 15:34
that's why you are getting an image of worse quality – Blackbelt Jul 11 '12 at 15:48

Android read image from sdcard. Wrong size

2 Answers2