How long does QR code scan take?

[Rick Solaro]

I am trying to use the QRcode reader and I can sit there with the QR code in the "viewfinder rectangle" for 30+ seconds and all it does is flashes little yellow lights in the corners of the QR code but never completes the scan.

Please advise.

[Sean Owen]

It takes about 0.1 seconds on a normal phone. This means something's wrong, like the code is invalid and will never scan. Impossible to say more without more info.

[Rick Solaro]

On closer inspection, the camera is reversing everything so that all images are mirrored, text is backwards, etc, which might be the reason it is invalid.  I am holding the camera up to QRcodes on my computer monitor.

Is this just a settings issue?  I have looked at my settings for the camera and the QRcode reader and it doesn't seem to work.

Have you heard of this issue?

Rick

[Sean Owen]

Yes, you can't flip a QR code. It is not valid when reversed. Are you talking about an Android device that's scanning it? When you use a front camera, the device will mirror the image when presented on screen since it is more intuitive to act like a mirror. But the image data is presented as seen, unmirrored, to the app. Of course that is only what should happen. From what I gather there may be devices that don't do this correctly, and then it just wouldn't work. I know Lachezar has just added a patch to efficiently scan for mirrored codes anyway, so in the build from HEAD now (and a future release) it shouldn't matter whether the device works correctly or not.

[Rick Solaro]

I see.  The device where my app will be installed is an Android tablet with a front-facing camera only.  Also, it is an aftermarket build that we had specially mass produced by a company in China, which may account for the incorrect behavior of the camera.

When should I expect the release that will work with mirrored QR codes?  Until I have it, I won't be able to utilize the QRcode reader in my tablet app at all.

[Sean Owen]

It will probably be months, can you build from SVN? I can post a current debug build if not.

[Lavan Kumar]

I am no professional, but can you try mirroring the QR code that you are scanning. Not a permanent solution but a quick fix i would say :)