How to make it possible to save raw photos on Samsung Galaxy A3 2017?

Question

I have a rooted Galaxy A3 2017 (SM-A320F) running Android 8.0.0. I'm trying to capture raw photos, but neither the stock Camera app nor Open Camera show any relevant options (I have enabled Camera2 API). This option wasn't present before rooting too. On another phone, unrooted Galaxy Note8, the option is present at least in Open Camera.

So I suppose the option is somehow disabled in my A3. Can it be re-enabled without switching to a completely different firmware? How?

Note that another question proposed as a duplicate is 1) asking about very old version of Android — 4.2.2, which doesn't have Camera2 API, and 2) asks simply whether there exist any apps with such functionality, which today is of course yes. So this one is not a duplicate. This question is about how to re-enable the missing raw photo support instead.

Answer 1

Camera2 API alone doesn't necessarily mean you can shoot RAW, though you can run the free app Manual Camera Compatibility. If it shows that your phone supports RAW, you should be able to shoot RAW with the Manual Camera app itself.

Photoshop Lightroom is another app capable of capturing and editing RAW, so maybe that's worth a shot aswell.

Answer 2

It appears to already be possible, with the stock firmware! I was about to try tracing an NDK-powered camera app (thanks to Sisik's tutorial with a demo) with strace to see which API calls lead to which ioctls to aid further searches, when, while trimming down the demo, I noticed that the native camera API exposes AIMAGE_FORMAT_RAW16 with dimensions 4144×3106 on my Galaxy SM-A320F/DS. After I went ahead and tried capturing an image in this format, I indeed got a true 16-bit Bayer output, which after simplistic demosaicing and white-balancing resulted in a pretty decent raw image.

There's a small strangeness though: the bottom part of the image (pixels 2333 through 3106) is always filled with zeros. I'm not sure why this is so, but at least the upper 75% of the data are present and usable.

How to get RAW support in OpenCamera

Currently, OpenCamera detects whether a camera supports RAW by REQUEST_AVAILABLE_CAPABILITIES_RAW. If there's no such capability, the detection simply gives negative result. For SM-A320F this is incorrect, because it doesn't report this capability, but RAW16 format is among the supported output formats.

To work around this misdetection, we can apply the following patch to OpenCamera 1.47.3, and build our own APK. This patch will stub out the check for the capability, making OpenCamera search for the format desired regardless.

diff --git a/app/src/main/java/net/sourceforge/opencamera/cameracontroller/CameraController2.java b/app/src/main/java/net/sourceforge/opencamera/cameracontroller/CameraController2.java
index 2c6463c..939b00b 100644
--- a/app/src/main/java/net/sourceforge/opencamera/cameracontroller/CameraController2.java
+++ b/app/src/main/java/net/sourceforge/opencamera/cameracontroller/CameraController2.java
@@ -2062,7 +2062,7 @@ public class CameraController2 extends CameraController {
         //camera_features.picture_sizes.get(0).supports_burst = false;

         raw_size = null;
-        if( capabilities_raw ) {
+        if( true || capabilities_raw ) {
             android.util.Size [] raw_camera_picture_sizes = configs.getOutputSizes(ImageFormat.RAW_SENSOR);
             if( raw_camera_picture_sizes == null ) {
                 if( MyDebug.LOG )

I've reported this at OpenCamera's issue tracker as ticket 661.