Save PreviewFrame as JPEG on external storage (Android)

Question

I am trying to save the preview frames from the camera on the external storage of my device.

These are the permissions in my Manifest:

<uses-permission android:name="android.permission.CAMERA" />
 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

And this is the Callback inside the surfaceChanged():

  mCamera.setPreviewCallback(new PreviewCallback() {

                public void onPreviewFrame(byte[] data, Camera camera) {
                    Camera.Parameters parameters = camera.getParameters();
                  Size size = camera.getParameters().getPreviewSize();
                  frames++;
                  Log.v("Framecount", "Frame: " + frames + "Größe: " + data.length);

                  int width = parameters.getPreviewSize().width;
                  int height = parameters.getPreviewSize().height;

                  ByteArrayOutputStream outstr = new ByteArrayOutputStream();
                  Rect rect = new Rect(0, 0, width, height); 
                  YuvImage yuvimage=new YuvImage(data,ImageFormat.NV21,width,height,null);
                  yuvimage.compressToJpeg(rect, 100, outstr);
                  Bitmap bmp = BitmapFactory.decodeByteArray(outstr.toByteArray(), 0, outstr.size());
                  Bitmap thumbnail = Bitmap.createScaledBitmap(bmp, 20, 20, false);
                try   {
                    File sdCard = Environment.getExternalStorageDirectory();
                    File dir = new File (sdCard.getAbsolutePath() + "/.aaaaaaaaa/");
                    dir.mkdirs();
                    File file = new File(dir, "filename.jpg");
                    FileOutputStream output = new FileOutputStream(file);
                  yuvimage.compressToJpeg(rect, 90, output);
                  output.flush();
                  output.close();
                }
                catch(Exception e) {
                    Log.v("Error", "Error");
                }



                }
              });

Showing the Preview frames on the screen is not the problem, I just can't save them. Does anyone have an idea what could be wrong?

`Log.v("Error", "Error");`. That does not tell you which exception happened. Better: `Log.v("Exception", e.getMessage());`. Also add an `e.printStackTrace();` to that catch block. Please tell which Exception you get. — greenapps, Jun 08 '15 at 17:12
`dir.mkdirs();`. No not like that. Better: `if (!dir.exists()) dir.mkdirs();`. And that is not fully ok too as you should inspect the return value of mkdirs() too and not continue if it fails. Display a toast saying so. Maybe a Toast is not allowed. If so just Log it and return. — greenapps, Jun 08 '15 at 17:14
Thanks for the tips: Logcat gives me the following errors with the tag mm-camera: isp_util_hw_notify_stats: TLDEBUG tintless frame id 1370, isp_tintless_bg_pca_stat_config: pointer okay, isp_tintless_bg_pca_stat_config: lib returned config err=0, dmlroc_entry entering dmlroc_entry — SparklingWater, Jun 08 '15 at 17:39
As you have discovered you will get many frames. So better change `File file = new File(dir, "filename.jpg");` to `File file = new File(dir, "filename." + frames + ".jpg");`.Your code works for me by the way. — greenapps, Jun 08 '15 at 17:39
Sorry i do not understand the errors you posted. What does it have to do with saving to file or Exceptions from that catch block? And i like to know the result of exists() and mkdirs(). How did you check that that hidden directory does not exist? — greenapps, Jun 08 '15 at 17:40
After making all the changes you recommended: !dir.exists() returns false, and it doesn't seem like there is an exception being thrown, Like you said it works for you and there are no errors, but I can't find the files on my sdcard. — SparklingWater, Jun 08 '15 at 17:48
`dir.exists() returns false,` Unclear!. Is that after mkdirs()? You should check it after mkdirs too if you do not return. Please edit your post here to show all exists() and mkdirs() code too. — greenapps, Jun 08 '15 at 17:50
`but I can't find the files on my sdcard.` Well how are you looking for them? And most probably they are not on a removable micro SD card but just on external memory of the device. Look at the path given by `file.getAbsolutePath()` — greenapps, Jun 08 '15 at 17:50
The Gallery app seems to cache the folder structure,so I just restarted my phone and now I am able to see the frames. Thank you for your help! — SparklingWater, Jun 08 '15 at 17:55
No. This code will not care for those pictures beeing visible in the Gallery. Only after reboot of your device this is possible. You should of course use a File Explorer app. In it's settings check 'show hidden files'. . Or do not use a hidden folder for a start. — greenapps, Jun 08 '15 at 17:57
If you want your jpg's immediately visible in the Gallery then invoke the media scanner on every new file. Search for the two lines of code on this site. — greenapps, Jun 08 '15 at 17:59

score 0 · Accepted Answer · answered Jun 08 '15 at 18:00

0

If you want your jpg's immediately visible in the Gallery then invoke the media scanner on every new file. Search for the two lines of code on this site.

answered Jun 08 '15 at 18:00

greenapps

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Save PreviewFrame as JPEG on external storage (Android)

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