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Show HN: QRaro, store binary data into QR Codes and retrieve it later

20 points by tcsenpai 2y ago

Of course this is just for fun

tcsenpai 2y ago
Update: added qrtools as a second decoder; now you can use 1000 (or more) chunks per qrcode. The pika image included can now be stored in just (!!) 124 qr codes. EDIT: And added gzip compression too
altbdoor 2y ago
I used to have a similar idea. In general, generate a series of QR codes for any file, and convert them into a GIF. But then I quickly realized I probably have to design a metadata structure (e.g., how many total QRs, where is start, where is end, etc). I didn't continue after that :-P Obviously this wouldn't scale in real world application, but it was a fun idea.
- tcsenpai 2y ago
  Oh yea indeed in each qr code there is a small header that indicates some metadata, is just a small string value that is useful for the decoder. I must admit claude sonnet helped in the most boring parts of it lol
ranger_danger 2y ago
Why not just use base64 or something
- matheusmoreira 2y ago
  Because that leads to lower capacity. For example, a 4096 bit RSA secret key will fit in a binary mode QR code but can't be stored base 64 encoded in a text mode QR code.
- vrighter 2y ago
  qr codes can store binary data. Base-64 is for stuff that can only store text. It otherwise wastes 2 bits per byte (25%)
- tcsenpai 2y ago
  cause it wasn't that funny imho
matheusmoreira 2y ago
This is great. Have you looked into QR code's structured append support? It provides the sequencing metadata required for reconstructing the data of multiple QR codes even if scanned out of order. It's limited and other schemes would still be valuable but it might still be worth supporting since it's native to the format. Does it have camera support? I added binary decoding feature to zbar a few years ago, zxing already had it and seemed to be in far better shape overall but zbar had builtin camera support which was necessary for my use case.
- tcsenpai 2y ago
  No I didn't look at that QR code feature, I am nowhere near an expert in that field so I am gonna dig to find what it is, especially if it can enhance the qr decoding which fails often on big files
rahimnathwani 2y ago
This reminds me of the Danmere Backer, a PC backup system that used VHS tapes. https://linbacker.sourceforge.net/screenshots.html https://linbacker.sourceforge.net/screenshots.html
- tcsenpai 2y ago
  Now i need to buy some vhs tapes

20 points by tcsenpai 2y ago

Of course this is just for fun

Update: added qrtools as a second decoder; now you can use 1000 (or more) chunks per qrcode. The pika image included can now be stored in just (!!) 124 qr codes. EDIT: And added gzip compression too

altbdoor 2y ago

I used to have a similar idea. In general, generate a series of QR codes for any file, and convert them into a GIF. But then I quickly realized I probably have to design a metadata structure (e.g., how many total QRs, where is start, where is end, etc). I didn't continue after that :-P Obviously this wouldn't scale in real world application, but it was a fun idea.

tcsenpai 2y ago
Oh yea indeed in each qr code there is a small header that indicates some metadata, is just a small string value that is useful for the decoder. I must admit claude sonnet helped in the most boring parts of it lol

ranger_danger 2y ago

Why not just use base64 or something

matheusmoreira 2y ago
Because that leads to lower capacity. For example, a 4096 bit RSA secret key will fit in a binary mode QR code but can't be stored base 64 encoded in a text mode QR code.
vrighter 2y ago
qr codes can store binary data. Base-64 is for stuff that can only store text. It otherwise wastes 2 bits per byte (25%)
tcsenpai 2y ago
cause it wasn't that funny imho

matheusmoreira 2y ago

This is great. Have you looked into QR code's structured append support? It provides the sequencing metadata required for reconstructing the data of multiple QR codes even if scanned out of order. It's limited and other schemes would still be valuable but it might still be worth supporting since it's native to the format. Does it have camera support? I added binary decoding feature to zbar a few years ago, zxing already had it and seemed to be in far better shape overall but zbar had builtin camera support which was necessary for my use case.

tcsenpai 2y ago
No I didn't look at that QR code feature, I am nowhere near an expert in that field so I am gonna dig to find what it is, especially if it can enhance the qr decoding which fails often on big files

rahimnathwani 2y ago

This reminds me of the Danmere Backer, a PC backup system that used VHS tapes. https://linbacker.sourceforge.net/screenshots.html https://linbacker.sourceforge.net/screenshots.html

tcsenpai 2y ago
Now i need to buy some vhs tapes