CODEWITHSUNDEEP
androidandroid-camerargb
nneonneo
nneonneo

Reputation: 179392

Reading RGB images with an ImageReader

I'm trying to use an ImageReader to get RGB images from the camera. I'm using the Camera2 API from Android 5.0 "L" on a Nexus 5 running the developer preview. Note that I am not asking how to convert YUV into RGB - I'm trying to get RGB directly from ImageReader. For anyone wanting to know how to convert YUV to RGB, feel free to consult another question, e.g. Convert Android camera2 api YUV_420_888 to RGB.

I already have a SurfaceView configured for RGB images which is working fine, and I believe that the camera hardware produces RGB data (because all the tone mapping and color gain settings on Android are specified to operate on RGB channels).

I can obtain YUV_420_888 images from ImageReader by creating the ImageReader this way:

imageReader = ImageReader.newInstance(W, H, ImageFormat.YUV_420_888, 4);

and then converting the YUV images to RGB. However, this is introducing both an unwanted quantization error (since my application requires RGB images), and unnecessary processing time.

However, when I try creating the image reader this way:

imageReader = ImageReader.newInstance(W, H, PixelFormat.RGB_888, 4);

the image capture fails with the following exception:

java.lang.UnsupportedOperationException: The producer output buffer format 0x22 doesn't match the ImageReader's configured buffer format 0x3.
        at android.media.ImageReader.nativeImageSetup(Native Method)
        at android.media.ImageReader.acquireNextSurfaceImage(ImageReader.java:293)
        at android.media.ImageReader.acquireNextImage(ImageReader.java:339)
        at android.media.ImageReader.acquireLatestImage(ImageReader.java:243)
        at <my code...>

I'm confused on two fronts. First, the output format mentioned, 0x22, is not in either PixelFormat or ImageFormat. It seems to be some sort of undocumented raw mode, but I can't use ImageReader.newInstance(W, H, 0x22, 4) to capture it (I get java.lang.UnsupportedOperationException: Invalid format specified 34). I would love to capture in the raw format but I can't convince ImageFormat to accept it (and the other raw format ImageFormat.RAW_SENSOR is incredibly slow for some reason).

Second, the SurfaceView is already happily consuming RGB_888 images (as far as I can tell), and putting them directly on the screen. So why isn't ImageReader not accepting RGB images properly? What did I do wrong?

Upvotes: 33

Views: 6756

Answers (1)

Darian-Cătălin Cucer
Darian-Cătălin Cucer

Reputation: 1

The error exception is because of PixelFormat.RGB_888 that isn't the same as ImageFormat.RGB_888.

PixelFormat.RGB_888 is equivalent to ImageFormat.RGB_565 not the one you used ImageFormat.RGB_888.

You have to use ImageFormat.RGB_888 instead of PixelFormat.RGB_888 like this:

imageReader = ImageReader.newInstance(W, H, ImageFormat.RGB_565, 4);

This allows to capture RGB from camera using ImageReader.

Upvotes: -1

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