I'm specifically asking if, and what, is the specification for formatting the text inside a QR code - not how to generate a code (which I can do).
I need to put hCard data into a QR code, however I don't know how to mark the QR code as VCF data (versus URL, text, etc) so the decoder knows what to do.
All the info I've seen online has to do with generating the QR code, not formatting the data inside.
Who says you have to pay for this info? just go to this page http://qrcodenet.codeplex.com/ and scroll to the bottom REFERENCES section and you should find a free download like tited 4. ISO/IEC 18004:2006(E) - QR code specification ISOIEC 18004_2006Cor 1_2009.pdf
There is no official specification for this -- the QR code spec does not say anything about the contents. Everything I know about the commonly-used and de facto formats and conventions is summarized in this wiki:
https://github.com/zxing/zxing/wiki/Barcode-Contents
See http://www.denso-wave.com/qrcode/qrstandard-e.html
and http://www.denso-wave.com/qrcode/aboutqr-e.html
QR Code is a kind of 2-D
(two-dimensional) symbology developed
by Denso Wave (a division of Denso
Corporation at the time) and released
in 1994 with the primary aim of being
a symbol that is easily interpreted by
scanner equipment.
...
QR Code is open in the sense that the
specification of QR Code is disclosed
and that the patent right owned by
Denso Wave is not exercised.
from http://www.denso-wave.com/qrcode/qrstandard-e.html:
QR Code is established as an ISO (ISO/IEC18004) standard. QR Code
specification can, therefore, be purchased from this organization.
Please seach by inputting ISO No.18004 to "Search
and ISO Catalogue".
http://www.iso.ch/iso/en/prods-services/ISOstore/store.html
In the past I have found information at http://www.nttdocomo.co.jp/english/service/imode/make/content/barcode/function/, a page which I can not trace (easily?) anymore.
See http://www.onbarcode.com/qr_code/ for helpful info - both about encoding and generating, and several libraries to use as well.
The official spec is available here from iso.org, but you have to pay for it.