|Transparant QR code|
Based on an idea of Zack Freedman twitter link, but then with full-color video background possible. Does not work on all readers, zbarimg fails on the PNG, but could be due to PNG alpha channel interpreted in the wrong way.
It is a patch to GPL code, so modified source must be published. For convenience, patch file is encoded in QR as well. Commit message redacted and reduced, xz compression, and it fits!
Sourcecode patch to libqrencode: (xz compressed patchfile)
Additional changes: Reduce location_ishiconstrast() remove the line 6 tests for even more area, seems to be allowed on most phone-based QR readers.
Sample image. Below transparent, PNG32 format file can be overlayed on any graphic and redirects to http://revspace.nl/