<p>Anyone know a QR decoder that works on mac or that might be online? I just need to decode one single image.</p>

Unfortunately, the most used library
libdecodeqr
is depends on OpenCV (gtk2) and it is too hard to compile it on OS X. (Tried to compile it because it is needed by
```
Image::DecodeQR
```
perl module - but unsuccessful).
Fortunately, found this link:
http://macscripter.net/viewtopic.php?id=37404
from citing the next:
Download the
ZBar source code
.
Unpack the the tarball, and open the resulting directory in a Terminal window.
Type
```
./configure --disable-video --without-python --without-gtk --without-qt
```
to configure the build process, limiting dependencies to ImageMagick.
Type "make" to invoke the build process.
Type "sudo make install", and enter an administrator password when prompted.
You will need
```
ImageMagick
```
what can be installed from
macports
.
After installing the ZBar, you can nicely decode qrcode with a command
```
```
zbarimg qrcode_file.png
```
```
Tested on OS X Mavericks 10.9.2 (and Lion/10.7.5)- and works nicely. Becasue it only depends on ImageMagick (exists in macports)- should be easily "compilable" on other OS X versions too.