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I would like to save a preview frame as a jpeg image.

I have tried to write the following code:

public void onPreviewFrame(byte[] _data, Camera _camera) { if(settings.isRecording()) { Camera.Parameters params = _camera.getParameters(); params.setPictureFormat(PixelFormat.JPEG); _camera.setParameters(params); String path = "ImageDir" + frameCount; fileRW.setPath(path); fileRW.WriteToFile(_data); frameCount++; } }

but it's not possible to open a saved file as a jpeg image. Does anyone know how to save preview frames as jpeg images?

Thanks

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6 Answers 6

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9

checkout this code. i hope it helps

camera.setPreviewCallback(new PreviewCallback() { @Override public void onPreviewFrame(byte[] data, Camera camera) { // TODO Auto-generated method stub Camera.Parameters parameters = camera.getParameters(); Size size = parameters.getPreviewSize(); YuvImage image = new YuvImage(data, ImageFormat.NV21, size.width, size.height, null); Rect rectangle = new Rect(); rectangle.bottom = size.height; rectangle.top = 0; rectangle.left = 0; rectangle.right = size.width; ByteArrayOutputStream out2 = new ByteArrayOutputStream(); image.compressToJpeg(rectangle, 100, out2); DataInputStream in = new DataInputStream(); in.write(out2.toByteArray()); } } }); camera.startPreview();
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1

You have to convert it manually, there are some examples on the android-developers list if you browse the archive - mostly dealing with the format (luminance/chrominance,etc) conversion, then writing the image to a bitmap, then saving to a file.

It's all a bit of a pain really.

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0

I set the PreviewFormat with Camera.Parameters.setPreviewFormat(PixelFormat.JPEG) before preview,but it seems that it can't really set the previewformat...... By the way, the default format of the preview is YCbCr_420_SP....

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0

You must first check what are the supported preview formats for your device by calling getSupportedPreviewFormats(). Make sure JPEG is supported before calling setPreviewFormat(PixelFormat.JPEG).

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0

JPEG is not a format for Camera Preview. As official documentation says,

"Only ImageFormat.NV21 and ImageFormat.YUY2 are supported for now"

In order to get a picture from Camera Preview, you need to define preview format, as below:

Camera.Parameters parameters; parameters.setPreviewFormat(ImageFormat.NV21); //or ImageFormat.YU2

After that, you compress & save JPEG as in Dany's example.

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Comments

-1

_data probably isn't in JPEG format. Did you call Camera.Parameters.setPreviewFormat(PixelFormat.JPEG) before calling start preview?

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1 Comment

all android cameras dosent support jpeg format for preview data

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