zbarimg fail to decode large QR code created by qrencode

[petterreinholdtsen]

This issue is originally reported to https://bugs.debian.org/719013 .

I just tested this with zbar version 0.22, and sure enough, the problem still exist:

$ yes | dd bs=1 count=3000 | qrencode -S -v 32 -o /tmp/foo.png
$ zbarimg /tmp/foo-0*
scanned 0 barcode symbols from 2 images in 0.16 seconds


WARNING: barcode data was not detected in some image(s)
Things to check:
  - is the barcode type supported? Currently supported symbologies are:
    . EAN/UPC (EAN-13, EAN-8, EAN-2, EAN-5, UPC-A, UPC-E, ISBN-10, ISBN-13)
    . DataBar, DataBar Expanded
    . Code 128
    . Code 93
    . Code 39
    . Codabar
    . Interleaved 2 of 5
    . QR code
    . SQ code
  - is the barcode large enough in the image?
  - is the barcode mostly in focus?
  - is there sufficient contrast/illumination?
  - If the symbol is split in several barcodes, are they combined in one image?
  - Did you enable the barcode type?
    some EAN/UPC codes are disabled by default. To enable all, use:
    $ zbarimg -S*.enable <files>
    Please also notice that some variants take precedence over others.
    Due to that, if you want, for example, ISBN-10, you should do:
    $ zbarimg -Sisbn10.enable <files>

$

I expected zbar to handle QR codes generated by qrencode.

[matheusmoreira]

I was able to reproduce this issue with zbarimg 0.23 as well as the master branch.

$ yes | dd bs=1 count=3000 | qrencode -S -v 32 -o 66.png
$ zbarimg --version
0.23
$ zbarimg -Sdisable -Sqr.enable 66-01.png 66-02.png 2>&1 | grep WARNING
WARNING: barcode data was not detected in some image(s)
$ zbar/zbarimg/zbarimg -Sdisable -Sqr.enable 66-01.png 66-02.png 2>&1 | grep WARNING
WARNING: barcode data was not detected in some image(s)

[jose1711]

possibly related: #65

[jose1711]

by looking at debug.svg it seems that grid finder got totally confused:

[bitcoinhodler]

I noticed this problem recently when attempting to split a large block of data into multiple QR codes to solve this issue. My workaround was to split the data myself and run qrencode multiple times to create separate QR codes, instead of running qrencode once to create a series of "structured append" codes.

It would be nice if zbarimg could decode these, and even better if it could somehow report the structured append metadata (sequence indicator and parity data).

[monperrus]

looking forward to seeing support for structured append in zbar!

[maglub]

@jose1711 how do you generate an debug.svg file?

[ionum]

@jose1711 You have to set DEBUG_SVG and recompile...

[markuzzi]

What is the status of this issue? Is there any chance to recover a QR code that is created with qrencode? It is very large.

[liyaodev]

Maybe try to upgrade zbarimg=0.23, It seem to be a similar issue that Polyconseil/zbarlight#33.

[petterreinholdtsen]

Do you mean you did not see the problem with zbarimg version 0.23, in contradiction to the message in #66 (comment) ? I hope the recipe to reproduce it is simple enough for anyone to test.